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De Wasseige C., Tadoum M., Eba’a Atyi R. & DOUMENGE C. (Eds.), 2015 – The forests of the Congo Basin. Forests and climate change. Weyrich, Belgium: 128 p.

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THE FORESTS OF THE CONGO BASIN
Forests and climate change
The Forests of the Congo Basin - Forests and climate change
Special issue of the State of the Forest ~ 2015 ~
Editors : de Wasseige C., Tadoum M., Eba’a Atyi R. and Doumenge C.
Cover picture: Open canopy of a rain forest in the south-west of Gabon. Photo taken from a track in a forest con-
cession. © Frédéric Sepulchre
The State of the Forest report is a publication of the Observatoire des Forêts d’Afrique cen-
trale of the Commission des Forêts d’Afrique centrale (OFAC/COMIFAC) and the Congo
Basin Forest Partnership (CBFP).
http://www.observatoire-comifac.net/ - http://comifac.org/ - http://pfbc-cbfp.org/
Unless stated otherwise, administrative limits and other map contents do not presume any official approbation.
Unless stated otherwise, the data, analysis and conclusions presented in this book are those of the respective authors.
All images are subjected to copyright. Any reproduction, electronic or any other form is prohibited without the
express prior written consent of the copyright owner.
The suggested citation is : The Forests of the Congo Basin - Forests and climate change. Eds : de Wasseige C.,
Tadoum M., Eba’a Atyi R. and Doumenge C. – 2015. Weyrich. Belgium. 128 p.
Legal deposit: D2015/8631/42
ISBN: 978-2-87489-355-1
Reproduction is authorized provided the source is acknowledged
© 2015 EDITION-PRODUCTION
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© Published in Belgium by WEYRICH EDITION
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THE FORESTS OF THE CONGO BASIN
Forests and climate change
TABLE OF CONTENTS
List of contributors 7
Acronyms 9
Preface 13
Introduction 15
CHAPTER 1
e importance of Central Africa’s forests 17
CHAPTER 2
Climate of Central Africa : past, present and future 37
CHAPTER 3
Interactions between climate characteristics and forests 53
CHAPTER 4
Vulnerability and adaptation of forests and communities in Central Africa 65
CHAPTER 5
e forests of Central Africa : an increased contribution to the mitigation of climate change 79
CHAPTER 6
Forest and climate change in Central Africa : Synergy between Mitigation and Adaptation 93
Conclusions 105
Bibliography 111
Annexes 125
7
List of contributors
Coordination
de Wasseige Carlos - OFAC
Text review and revision
de Wasseige Carlos - OFAC
Charles Doumenge - CIRAD
Bedoret Brigitte
Halleux Claire - OFAC
Translation
Ducenne Quentin – R&SD sia
Deroo Catherine – R&SD asbl
Rollinson Simon - Pacic Island Projects
Map design
Halleux Claire - OFAC
de Wasseige Carlos - OFAC
Page design and settings
Weyrich S.A.
de Wasseige Carlos - OFAC
Authors
Bayol Nicolas - FRMi
Beyene Tazebe - University of Washington
Bodin Blaise - UNEP - WCMC
de Wasseige Carlos - OFAC
Dessard Hélène - CIRAD
Doumenge Charles - CIRAD
Eba’a Atyi Richard - CIFOR
Feintrenie Laurène - CIRAD
Gond Valery - CIRAD
Haensler Andreas - CSC
Hiol Hiol François - University of Dschang
Hirsch Flore - FRMi
Kengoum Félicien - CIFOR
Laraque Alain - IRD
Loh Chia Eugene - CIFOR
Ludwig Fulco - Wageningen University
Mahé Gil - IRD
Manetsa Djoufack Viviane - University of Yaoundé I
Marquant Baptiste - FRMi
Marshall Michael - ICRAF
Martius Christopher - CIFOR
Mkankam François - Université des Montagnes
Molto Quentin - FRMi
Mosnier Aline - IIASA
Ndjatsana Michel - COMIFAC Executive Secretariat
Pérez-Terán Alba Saray - CIFOR
Pokam Wilfried - University of Yaoundé I
Schmidt Lars - FRMi
Scholte Paul - GIZ
Sonwa Denis - CIFOR
Sufo-Kankeu Richard - CIFOR
Tsalefac Maurice - Universities of Dschang and Yaoundé I
Other contributors
Assembe-Mvondo Samuel - CIFOR
Batti Ahmed - FRMi
Chevalier Jean-François - FRMi
Tadoum Martin - COMIFAC Executive Secretariat
9
ACRONYMS
AF Adaptation Fund
AfDB African Development Bank
AGEDUFOR Appui à la Gestion Durable des Forêts de la
RDC
ARECO Association Rwandaise des Ecologistes
ASAP Adaptation for Smallholder Agriculture
Program
ASECNA Agence pour la Sécurité de la Navigation
Aérienne en Afrique et à Madagascar
AUDD Avoided Unplanned Deforestation and
Degradation
AU-NEPAD African Union - New Partnership for
Africa’s Development
BBOP Business and Biodiversity Offset Program
BIOM Biosphere Management Model
BMU German Federal Ministry for the
Environment
BP Before present
BSM Benefit-sharing mechanisms
CA Central Africa
CAR Central African Republic
CBFF Congo Basin Forest Fund
CBFP Congo Basin Forest Partnership
CCAFS Climate Change, Agriculture and Food
Security
CDM Clean Development Mechanism
CED Center for Environment and Development
CEMAC Central African Economic and Monetary
Community
CER Certified Emission Reductions
CGIAR Consultative Group on International
Agricultural Research
CICOS International Commission for the Congo-
Oubangui-Sangha Basin
CIFOR Center for International Forestry Research
CIRAD Center for International Agricultural
research for development
CN REDD REDD National Coordination
CNCM National Centre for Meteorological
Research - Coupled Models
CNRS National Center for Scientific Research
CO2 Carbon dioxide
COBAM Climate Change and Forests in the Congo
Basin
CoFCCA Congo Basin Forests and Climate Change
Adaptation
COMIFAC Central African Forests Commission
COP Conference of the Parties
CSC Climate Service center
DFID Department for International Development
DMC Disaster Monitoring Constellation
DRC Democratic Republic of Congo
EbA Ecosystem-Based Adaptation
ECCAS Economic Community of Central African
States
ECHAM European Centre Hamburg Model
ECOFORAF Eco-certification of forest concessions in
central Africa
ENSO El Niño Southern Oscillation
ERA Extension of Rotation Age
ESA European Space Agency
EU European Union
FAO Food and Agriculture Organization
FCPF Forest Carbon Partnership Facility
FIP Forest Investment Program
FLEGT Forest Law Enforcement, Governance and
Tra de
FORAFAMA Support for the sustainable management of
forests in the Congo Basin and the Brazilian
Amazon Basin
FRA Forest Resources Assessment
FRELs Forest Reference Emission Levels
FRLS Forest Reference Levels
FRM Forêt Ressources Management
FSC Forest Stewardship Council
FSCD ClimDev Special Fund
FSF Fast-Start Financing
GCCA Global Climate Change Alliance
GCF Green Climate Fund
10
GCM Global Climate Models / General
Circulation Model
GCOS Global Climate Observing System
GCS Global Comparative Study
GDP Gross domestic product
GE Green economy
GEF Global Environment Facility
GHG Greenhouse Gas
GIZ German Agency for International
Cooperation
GLOBIOM Global Biosphere Management Model
GTS Global Telecommunication Systems
HCVF High Conservation Value Forests
ICF International Climate Fund
ICRAF International Centre for Research in
Agroforestry
IFAD International Fund for Agricultural
Development
IFM Improved Forest Management
IIASA International Institute for Applied Systems
Analysis
IKI International Climate Initiative
INDC Intended Nationally Determined
Contribution
INDEFOR National Institute for Forest Development -
Equatorial Guinea
IOC Interoceanic Convergence
IPCC Intergovernmental Panel on Climate
Change
IPSL Institut Pierre Simon Laplace des Sciences
de l’Environnement Global
IRD Institute of Development Research
ITCZ Inter-Tropical Convergence Zone
ITF Inter-Tropical Front
IUCN International Union for Conservation of
Nature
JMA Joint Mitigation and Adaptation Mechanism
JRC Joint Research Centre
LCBC Lake Chad Basin Commission
LDC Least Developed Countries
LDCF Least Developed Countries Fund
LED Low Emissions Development
LEDS Low Emissions Development Strategy
LPJ-ml Lund-Potsdam-Jena-managed lands
LTPF Logged to Protected Forest
LUCF Land-Use Change and Forestry
MDG-F Millennium Development Goals
Achievement Fund
MODIS Moderate Resolution Imaging
Spectroradiometer
MRV Measurement, Reporting and Verification
NAP National Adaptation Plan
NAPA National Adaptation Program of Action
NCBs Non-Carbon Benefits
NCs National Communications
NGO Non Governmental Organization
NTFP Non-Timber Forest Product
OECD Organization for Economic Co-operation
and Development
OFAC Observatory for the Forests of Central
Africa
OLB Origin and Legality of Timber
ORSTOM Office of Scientific and Technical Research
Overseas
PAPPFG Gabonese project for development of small
forestry permits
PES Payments for Ecosystem Services
PFES Payment for Forest Ecosystem Services
PNIA National Agricultural Investment Program
PPCR Pilot Program for Climate Resilience
PS6 Performance Standards 6
RAFM African Network of Model Forests
REDD Reducing Emissions from Deforestation and
Degradation
REDD - PAC REDD+ Policy Assessment Centre
RIL Reduced Impact Logging
RMTN Regional Meteorological Telecommunication
Network
ROSE Network of local NGOs in south-eastern
Cameroon
R-PIN Readiness Plan Idea Note
R-PP Readiness Preparation Proposal
SATCOM Satellite Communications
11
SBSTA Subsidiary Body for Scientific and
Technological Advice
SCCF Special Climate Change Fund
SFM Sustainable forest management
SIEREM Système d’Informations Environnementales
sur les Ressources en Eau et leur
Modélisation
SIS Safeguard Information Systems
SOF State of the Forest
SPA Strategic Priority for Adaptation
SRES Special Report on Emission Scenarios
SST Sea Surface Temperatures
TLTV Timber Legality and Traceability
Veri f icat i on
TREES Tropical forest monitoring from Satellite
remote sensing
UCL Catholic University of Louvain
UEFA Union pour l’Emancipation de la Femme
Autochtone
UK United Kingdom
UN United Nations Organization
UN-DESA United Nations Department of Economic
and Social Affairs
UNDP United Nations Development Programme
UNEP United Nations Environment Programme
UNFCCC United Nations Framework Convention on
Climate Change
UN-REDD United Nations Programme on Reducing
Emissions from Deforestation and Forest
Degradation
VCS Verified Carbon Standard
VIC Variable Infiltration Capacity
VPA Voluntary Partnership Agreement
WAM West African Monsoon
WATCH Water and Global Change
WCMC World Conservation Monitoring Centre
WFD WATCH Forcing Data
WMO World Meteorological Organization
WRI World Resources Institute
12
13
PREFACE
For several decades, climate change has been a fixture on the
global agenda as a highly dangerous scourge whose consequences
can jeopardise the survival of the planet and all humanity. Since
1992 the international community has been trying to find solu-
tions to the problem. In fact, the United Nations Framework
Convention on Climate Change and the Kyoto Protocol adopted
respectively in 1992 and 1997 laid down the legal basis for inter-
national cooperation to combat the causes and effects of climate
change around the world.
While the adoption of these instruments held much promise,
their implementation has proven more complicated in light of
difficulties faced by the country parties to annex 1 in fulfilling
their commitments to reduce greenhouse gas emissions (GHG).
Furthermore, funding provided in support of climate change
adaptation and mitigation efforts in developing countries has
fallen short of needs and expectations.
It was in a bid to provide a more comprehensive and better
coordinated response to the scourge that a new round of negotia-
tions has been underway for a few years with the aim of adopt-
ing a new global climate agreement. The 21st Conference of the
Parties to the Convention, slated to take place at the end of 2015
in Paris would be the culmination of these negotiations where the
international community is expected to adopt the new cooperation
instrument.
Similar to other Parties to the Convention, the Central African
countries have been actively involved for years in international cli-
mate change negotiations. Concerted positions on various issues
and topics of interest to the sub-region have been regularly devel-
oped and defended by these countries during negotiations. In fact,
given that the Central Africa harbours the Congo Basin forests, the
world’s second largest contiguous tropical forest, the sub-region’s
countries have always desired to see the role of these forests being
taken into account in the fight against climate change.
As a matter of fact, tropical forests play an undeniable role in the
fight against climate change. According to the Intergovernmental
Panel on Climate Change (IPCC), deforestation in tropical areas
accounts for approximately 15 % of GHG emissions. In this
respect, it has been recommended that the trend be reversed by
putting in place policies and actions at national level to combat
deforestation ; hence the emergence of the reduction of emissions
resulting from deforestation and forest degradation mechanism
(R EDD+).
The Congo Basin countries have an exemplary record in pre-
serving their forest resources. The last 2013 State of the Forests
Report (EDF) is quite revealing in this respect, as the sub-region
registered very low deforestation and degradation rates (0.14 per
cent per year) compared with other tropical regions around the
world. The REDD+ mechanism which is supported by most
countries in Central Africa is rightly regarded as a development
opportunity for these countries. Considering the countries’ long
and medium term aspirations for economic growth and develop-
ment, implementing the REDD+ strategy should help the Central
African countries access the funding and technologies necessary
to minimize their carbon footprint, by modernizing their agricul-
tural and livestock production systems, etc.
While the REDD+ concept may seem easy on the face of it,
the pre-requisites for its implementation at national level are more
complex. In fact, several methodological and technical aspects
constitute hurdles to the operationalization of this instrument by
our countries.
Beyond REDD+-related issues, climate change adaptation
issues are also a priority for the sub-region. There has been an
increase in extreme events arising from climate change with con-
sequences for both ecosystems and populations. There is therefore
a need to take action by putting in place appropriate measures and
actions to make these populations less vulnerable.
To address all these challenges, the Central African countries
must of necessity develop an integrated approach to addressing cli-
mate change with forests being an important part of this strategy.
It is in consideration of the foregoing, that it was deemed need-
ful within the framework of the 21st Conference of the Parties to
the Convention in Paris, to take stock of the dual issue of “for-
ests and climate change” in Central Africa. This report on for-
ests and climate change produced by the Central African Forest
Commission (COMIFAC) with the support of its partners aims to
update the international community and the authorities of coun-
tries in sub-region on progress achieved in sustainable forest man-
agement and tools being developed for REDD+ on the one hand,
and issues and challenges related to climate change mitigation and
adaptation on the other hand.
In the hope that this report will help to strengthen the Central
African countries’ advocacy at current and future international
negotiations on climate change in Central Africa,
I wish you all a pleasant reading,
Raymond Mbitikon
Executive Secretary of the
COMIFAC
15
INTRODUCTION
On the occasion of the 21st Conference of Parties (COP) to
the UN Framework Convention on Climate Change (UNFCCC)
held in Paris from 1 to 10 December 2015, the member States of
the COMIFAC wish to address the climate issues for their region
and in particular with regard to the role of forests. As a result, the
COMIFAC is proud to release this special publication on climate
and forests in Central Africa. The redaction of this special report
was put under the coordination of the Executive Secretariat of
COMIFAC and OFAC with support from CIFOR.
This report is the fruit of a long participatory process of infor-
mation gathering, exchanges between experts, debates and the
building of consensus to provide elements for the improved sus-
tainability of the Central African ecosystems. This vital under-
taking responds to a groundswell request from diverse stakehold-
ers for consolidated information in a joint report. The process of
creating the report comprises many stages, wherein many actors
are involved over a period of more than one year. The production
of this new edition began in October 2014 on the occasion of the
CBFP meeting in Brazzaville.
The drafting of each chapter is led by a ‘chapter coordinator’.
His role is to :
(i) Propose a structure for the chapter, based on the topics
proposed,
(ii) Stimulate the group of co-authors to generate their
respective contributions,
(iii) best achieve arranging of the different contributions,
and
(iv) Prepares the first version of the chapter for the review-
ing workshop and the final chapter based on feedback
received from the workshop.
The 3 days workshop held in Kribi in July 2015 constituted
a key step in the production of this publication. The principal
goal of the workshop was to encourage the authors and partners
of the Congo Basin forest sector to examine, amend and validate
the texts proposed for publication. In that sense, the workshop
can be considered as a “real time peer reviewing” process. First,
each draft chapter, including its themes and key elements, was
presented, thus enabling each participant to identify the topics to
which they could best contribute. Secondly, the participants were
divided into working groups so as to make suggestions and contri-
butions towards improving chapter content. During these discus-
sions, there was a high degree of participation, and participants
helped to make available to the authors better and more accessible
information. The authors then proceeded to work on these texts.
Once the texts – often drafted partly in French and partly in
English – have been finalized, a proofreading committee works on
improving their coherence and presentation in order to reach as
wide an audience as possible. The translation, formatting, proof-
reading, printing and dissemination of the document are the final
stages in this adventure, but they are nonetheless intensive and
time-consuming and involve substantial human resources.
In terms of content, this special publication pays primary
attention to forests, the climate and the possible policies linked to
this topic. Its content, divided into 6 chapters is the result of the
collaboration of many stakeholders.
The first 3 chapters focus on describing the central African
forest and climate features with scientific evidences, but also the
relations and mutual interaction between the forest and the cli-
mate.
The first chapter describes the key role of tropical African for-
est as a reservoir of carbon and biodiversity. Thanks to the latest
development in remote sensing technologies, the state of forests
and the dynamics of tropical forest cover types are increasingly
well described. It addresses also the cause of forest cover changes
and the possible evolution of the forest cover with regards with
new economic development opportunities, demography increase
and political and management challenges.
The second analyzes the Central African climate, concentrat-
ing in particular on (i) the key features of the climate, (ii) the his-
torical evolutions and changes (iii) the way in which this climate
could change in years to come, and (iv) the possible impacts of
these changes on the hydrological regime, evaporation and conse-
quently on the vegetation and human population.
After having described the forest and the climate of central
Africa, the third chapter addresses the question of the relation
between these 2 elements. This is made through the exchanges
in water content, the energy conversion with the role of the sen-
sible and latent heat and the influence of atmospheric carbon. The
chapter analyses also the historical mutual influence with veg-
etation extent driven by the climate evolutions and the possible
impact of climate modifications on vegetation and conversely the
impact of deforestation on the climate features.
The second part, with the 3 last chapters, is related to policies
issues and options to face the challenges of sustainable forest in a
context of climate change issues.
16
The chapter 4 is dedicated to vulnerability and adaptation of
forest and communities in a situation of changing climate. Indeed
not only the biophysical aspect are important to address, but also
the changes in environmental policies related to access to forest
resources in a context of increasing pressure on natural resources
mainly due to population increase. The vulnerability is also
depicted with regards to the economic and social sectors, hydrol-
ogy and energy, agriculture, health and urbanization. Then, the
adaptation is tackled regarding the ecosystem point of view, recall-
ing that the forest provide ecosystem goods and services, then,
regarding the policies and strategies, with some Lesson learnt from
early initiatives.
The fifth chapter is addressing the contribution of forests in
the mitigation to climate changes. Indeed, the forest analyzed
as a carbon stock, a carbon sink or as carbon emission, is a key
aspect for the carbon balance assessment and climate based poli-
cies. Mitigation of climate change is approached by three main
sets of policies and measures i.e. sustainable forest management
techniques, the improvement of forest governance and the current
engagement in the REDD+ process. There is also a new thinking
to favour traditional policies that additionally provide climate
regulation services as co-benefit while internalizing new interna-
tional initiatives such as Reducing Emissions from Deforestation
and forest Degradation (REDD+). The status and the implemen-
tation of REDD+ in central Africa, together with Lessons learned
from early mitigation initiatives and the remaining challenges, the
region have to face are also described in the chapter.
In the Congo Basin countries given that there is urgency for
both mitigation and adaptation actions, the sixth and last chapter
analyses the synergies and trade-offs between mitigation, adapta-
tion and development interventions. This chapter addresses the
political a nd institutional prerequisite for sy nerg ies in central Af rica
while stressing the importance of multi-sectorial approaches and
the roles of the different actors in the designing and implementa-
tion of actions tackling both adaptation and mitigation outcomes.
Entry points for synergy is illustrated through the promotion of
carbon and non-carbon benefits together, and the new tendency
towards the Joint Adaptation and Mitigation Mechanism (JMA)
proposed as a non-market based alternative to REDD+.
17
CHAPTER 1
The imporTance of cenTral africas foresTs
Baptiste Marquant1, Aline Mosnier2, Blaise Bodin3, Hélène Dessard4, Laurène Feintrenie4, Quentin Molto1, Valéry Gond4, Nico-
las Bayol1
With contributions from : Ahmed Batti, Richard Eba’a Atyi, Jean-François Chevalier and Charles Doumenge
1FRMi, 2IIASA, 3UNEP-WCMC, 4CIR AD
1. Introduction
Tropical forests are extraordinary reservoirs
of carbon and biodiversity. Within a few dec-
ades they have become a centre of attention in
the scope of international challenges in climate
change and conservation. The Congo Basin is the
second largest tropical forest in one piece after
the Amazon. Relatively well preserved, it plays
an important role in the regulation of global and
continental climatic systems.
These Central African forests provide subsist-
ence means to 60 million people who live either
inside or in the vicinity of the forests. They also
fulfil social and cultural functions essential to
local and indigenous populations, and contribute
to feed 40 million people who live in the urban
centres close to these forestry areas (Nasi etal.,
2011 ; de Wasseige etal., 2014). The importance
of tropical forests in the Congo Basin has gradu-
ally given these ecosystems the value of a world
common asset and many multilateral agreements
address today the management and conserva-
tion of these ecosystems in partnerships with the
states of the region.
Since the first field works until the latest
developments in remote sensing technologies, the
state of forests and the dynamics of tropical forest
cover types are increasingly well described. This
crucial knowledge is a central prerequisite for the
definition and then monitoring of national and
international economic and environmental poli-
cies. They require some important funding that
the States alone cannot provide. As a matter of
illustration, the REDD+ process in which several
countries in the Congo Basin have got involved
incurs the set-up of an integrated Measurement,
Reporting and Verification system (MRV) of
changes related to deforestation and / or forest
degradation1 as well as those resulting from an
improvement of the forest cover. Identifying and
mapping areas where the forest cover has been
changing and, more generally, land use charac-
teristics is central to the elaboration of policies
locally adapted to on-going dynamics.
Photo 1.1 : e
African Padauk
(Pterocarpus sp.),
is a tree species
prized by logging
companies
1 e denition of « forest degrada-
tion » or « degradation of forests »
in tropical humid forest is subject
to many debates among experts
and scientists. is article does
not address this topic.
©Frédéric Sepulchre
18
2. Forest types and forest cover in 2015
Schematically speaking, the Congo Basin
consists of five main forest types as follows :
- A central zone which includes a huge
swampy forest, hard to access, hence less
impacted by human activities – except hunting
– as compared to other forest types ;
- Around this central basin, the bulk of
the Congo Basin’s forests is dryland rainforest,
sometimes relatively well preserved but more or
less fragmented depending on the degree of deg-
radation from anthropogenic origin ;
- In the north and in the south of the Congo
Basin dryier forests types are found, adapted to
more seasonal climates ;
- Moving away from the centre of the basin,
one finds patchwork forests and savannahs where
dense forest areas alternate with grassland areas ;
- Finally, woodlands and wooded savannahs
(savannah including isolated trees) cover some
important areas in i) the north of Cameroon and
in CAR showing a northern degradation trend
towards the Saharan desert, and ii) in the south
of DRC.
A representation of the main land cover types
and their areas is given in Figure 1.1. The rain-
forests stretches on about half of Central Africa
(excluding Chad Sahelian country). A more
accurate mapping of forest types in the Congo
Figure 1.1 : Forest cover in Congo Basin and forest covers loss between 2000 and 2012 according to data
from MODIS Land Cover Type product – MCD12Q1
Source : Hansen etal., 2013
19
2 Using Landsat imagery, complex
IT methods involving a lot of data
allow to query each Landsat pixel
and dene forest covers according
to threshold values given to Land-
sat pixels for characterized forest
cover types (Potapov etal., 2012).
Basin and related carbon sinks is discussed fur-
ther in this chapter (see Figure 1.5).
The forest cover is usually determined
through satellite monitoring. In the Congo Basin
and as technologies evolve, several initiatives have
been launched. Approaches involving satellite
monitoring at national scale offer some advantage
in terms of accuracy but they make further sub-
regional comparisons between countries more
difficult, notably because of lack of standardiza-
tion in mapping classes and definitions. Besides,
satellite monitoring at national scale is seldom
comprehensive even at the country scale as a
result of the lack of funding (Desclée etal., 2014).
Assessments of the sub-regional forest cover
in the Congo Basin have developed for several
years. A comprehensive cartography technology
– wall-to-wall – which needs important satel-
lite imagery processing with advanced technical
tools2 delivers its first results and enables some
monitoring of the evolution of the forest cover
loss at a regional scale. The Figure 1.1 shows
areas where the forest cover loss exceeds 30 %
and where some forest stand disturbance was
observed between 2000 and 2012 (Hansen etal.,
2013). This data processing allows to assess the
deforestation between 2000 and 2012 to circa
4.6 % of the remaining rainforest cover in 2012
(Table 1.1).
Research on mapping forest cover currently
focus on the processing of radar signals that will
allow to address cover changes despite the con-
straint of clouds, main hindrance to proper inter-
pretation of satellite imagery in the Congo Basin.
A more accurate interpretation of the forest deg-
radation according to the drivers of deforestation
is also in progress.
In parallel to mapping forest cover, numerous
studies allow to assess the changes in the forest
cover in the entire Congo Basin. Data presented
hereafter originates from works carried out in the
scope of the TREES/FRA approach, and from
chains of processing based upon DMC, SPOT
and Landsat imagery using a 30 m resolution in
each case (Rasi et al., 2013). Thus, only small
and isolated distorted areas less than 30 m in size
could remain undetected in terms of forest cover
change. The area of this noise is reportedly small,
but yet is the technical limit of this study.
Figure 1.2 gives the estimations of deforesta-
tion rate by country over the entire rainforest
in Central Africa between 1990 and 2000 and
between 2000 and 2010. The gross deforesta-
tion added to afforestation, reforestation and for-
est regeneration gives the net deforestation. The
general trend is some decrease in the deforesta-
tion rate coming from 0.19 % to 0.14 % for the
whole rainforest in the Congo Basin while affor-
estation decreases or even becomes negligible.
A similar analysis carried out in dry forests
in Central Africa is given in Figure 1.3. While
gross deforestation is approximatively the same
between 1990 and 2000 and between 2000 and
2010, respectively 0.36 % and 0.42 %, the refor-
estation drop from 0.14 % to 0.03 % between
these two periods of time.
The dynamics of the private sector in the
Congo Basin may indicate an upward trend
intree plantations. New projects have been
launched in Gabon, for example, as an initiative
from companies such as Lignafrica.
Table 1.1 : Land cover surfaces in 2012 and forest cover loss since 2000 of the COMIFAC countries
Strata Surfaces km² (Proportion %)
With Chad Without Chad
Water 140 332 (3) 92 452 (3)
Dense humid forest 1 707 185 (36) 1 706 256 (48)
Wooded savannahs 1 167 234 (24) 1 143 835 (32)
Shrub savannahs 129 363 (3) 125 999 (4)
Grass savannahs 355 581 (7) 219 522 (6)
Farmland or grassland 508 291 (11) 225 217 (6)
Low or absent vegetal biomass 782 585 (16) 71 463 (2)
TOTAL 4 790 571 (100) 3 584 744 (100)
Forest cover loss > 30 % 78 726 (4.6)
20
Figure 1.2 : Annual deforestation rates (gross and net) of Central Africa
rainforests between 1990 and 2000, and between 2000 and 2010.
Sources : UCL (1990-2000) andJRC (2000-2010) in Desclée etal., 2014
Figure 1.3 : Annual deforestation rates (gross and net) of dry forests in
Central Africa between 1990 and 2000, and between 2000 and 2010.
Sources : JRC in Desclée etal., 2014
The forest cover cartography of the Congo
Basin is a valuable support tool for decision-
making in the scope of elaboration and moni-
toring of climatic and environmental policies.
This tool, often static in the past, is nowadays
built in the context of studying forest cover
and land use dynamics, and allows targeting
priority intervention zones relevant to public
policies and international agreements pertaining
to climate. This cartography of forest types and
related threats might play an increasing role in
the development of country planning and land
use planning in line with both national and local
problems, and in line with international commit-
ments made by States.
3. Drivers of deforestation and degradation
Policy programmes defined by Central Africa
States aim at economic emergence in 2025
(Regional Economic Programme from CEMAC)
or 2030 and 2035 (DRC and Cameroon). These
programmes are based upon the continuation of
natural resources exploitation (wood, oil, and
minerals), agricultural production for domestic
needs and exports, as well as the strengthening of
industrial processing activities. Forests in Central
Africa have so far been relatively well protected
thanks to low demographic pressure reinforced
by rural exodus, difficult access, absence of
transport and communication infrastructure,
and a business climate very little conducive to
long term investments (Burgess et al., 2006 ;
Megevand et al., 2013). Social and political
stability prevailing over the last decade in certain
countries of the sub-region has allowed the devel-
opment of large-scale road infrastructure, power
supply in the main urban areas and counties, and
an improvement in the business climate. Added
to this context, the rise in the price of minerals
and agricultural products in the international
market place in the early 2000s have acted like
investment incentives. At present, small-scale
agriculture and to a lesser extent the harvest
of fuelwood are considered the main drivers of
deforestation in the Congo Basin (Defourny
etal., 2011) but projects for large scale agribusi-
ness plants are developing in various countries
and may become more and more important in
the future.
-0.05%
0.00%
0.05%
0.10%
0.15%
0.20%
0.25%
0.30%
90-00 00-10 90-00 00-10 90-00 00-10 90-00 00-10 90-00 00-10 90-00 00-10 90-00 00-10
Cameroon CAR Congo DRC Eq. Guinea Gabon Humid Forests
Gross minus Net Deforestaon Net Deforestaon
0.00%
0.20%
0.40%
0.60%
0.80%
90-00 00-10 90-00 00-10 90-00 00-10 90-00 00-10 90-00 00-10
Cameroon CAR Chad DRC Dry Fore sts
Gross minus Net Deforestaon Net Deforestaon
21
3.1 Agriculture and agro-industries
Historically, agriculture was covering large
areas in the Congo Basin. Current research,
based on phytoliths and some fragments of char-
coal or tools used by men show that prior to the
triangular trade and more recently the massive
rural exodus towards urban areas, the vast major-
ity of forests in Central Africa was spotted with
agricultural areas (Morin-Rivat et al., 2014).
Agriculture currently practiced and spread
in the sub-region is either household-based or
small-scale. This subsistence agriculture lies on
fields combining various annual and perennial
edible crops (mainly cassava, maize, groundnut,
banana, vegetables and tubers) alternating with
short or long-term fallows depending on local
land availability (Meunier etal., 2014 ; Feintrenie
etal., 2015). Fallows can last over more than 20
years in less populated forest regions or conversely
they can be as short as 3 years in regions where
access to land is under harsh competition (Floret
et al., 1993 ; Feintrenie etal., 2015). On forest
fringes, some pieces of arable land are under per-
manent cultivation.
Slash and burn subsistence agriculture is
partly a driver of forest degradation but allows
some plant species adapted to perturbation to
maintain themselves in otherwise unfavourable
habitat. It results in deforestation only when the
anthropogenic pressure exceeds an estimated
threshold of 8 inh./km² in the Congo Bassin
(Desclée et al., 2014). Beyond this population
density peasants are obliged to decrease the fal-
low length in order to increase production and
meet minimal food needs.
The settlement of shifting cultivation and
preventing from using fire to clear land could
lower the impact of this activity on forest cover
and decrease the release of carbon in the atmos-
phere. Techniques of ecological intensifica-
tion of agriculture can provide solutions in this
direction. They are based on a shallow plough-
ing, keeping some protection on the soil such
as covering plants or mulching, as well as some
improvement of soil fertility through an adequate
combination of species and crop rotation. These
three principles are the pillars of conservation
agriculture (Corbeels etal., 2014) and are also
used in agroforestry systems (Nair, 1985). Several
applied research projects have been undertaken
to adapt these techniques to specific agriculture
conditions encountered in the rainforest context
and in relation with the issue of fuelwood pro-
duction. This is the case of the Makala Project
in DRC (Marien etal., 2013) and others in the
Amazonian Basin (Sist etal., 2014). Some tech-
niques are also under development, with the
enrichment of soils with small charcoal particles
and organic matter, mimicking the formation of
black earth (or terra preta) from the old Indians
of the Amazon. These production techniques
still need to be tested and assessed then popular-
ized in order to go beyong the research activity
and to become operational in rural households in
the Congo Basin.
Household farming goes beyong food pro-
duction to meet the needs of the producers them-
selves. A growing urban population means some
increasing needs for food and prompt farmers
benefiting from a marketing chain to produce
more. It is about household farming or non-
industrial farming involved with a combination
of subsistence farming, oil palm and cocoa tree
production. The main issues arising from this
type of commercial non-industrial agriculture
are of social nature, before being of environmen-
tal nature, because it involves land acquisition
by “village elites” (Pédelahore, 2012 ; Ndjogui
etLevang, 2013) or encroachement of pieces of
land under forest management without any con-
trol neither by the administration nor by the log-
ging companies.
Photo 1.2 : Itinerant house-
hold agriculture
Photo 1.3 : Industrial plant-
ing of oil palm trees
©Laurène Feintrenie
©Laurène Feintrenie
22
Industrial agriculture in Central Africa is
dominated by European, Asian and domestic
investments and is mainly about palm oil, natu-
ral rubber, banana and sugarcane (Feintrenie,
2014). The majority of industrial plantations
were established between 1910 and 1960. Today,
some of them are neglected waiting for a new
start, some of them are being rehabilitated, but
very few have been under permanent manage-
ment and exploitation.
For this historical reason, industrial plant-
ing have not caused major deforestation until
recently. However, this is changing because new
concessions are being granted inside the forest
zones. Thus, some areas under forest manage-
ment are removed from permanent forest land
and can be converted into agricultural land. This
land use alteration results in deforestation of
those pieces of land granted to the agribusiness.
However, there are success stories of agro-indus-
trial projects such as those in the mining indus-
try. These successful projects are undertaken by
companies which abide by national regulations
and implement social responsibility and environ-
mental accountability policies or engage in certi-
fication processes (Feintrenie etal., 2014).
3.2 Mining activities
The African continent would include 30 % of
the world reserves of minerals and one ca n assume
that at least 60 % of that total is under the forest
of the Congo Basin (Edwards et al., 2014). Just
like other natural resources, industrial mining
requires permits. Many mining exploration per-
mits have been granted by the Central African
countries and such permits concern large areas
of rainforests already granted to logging compa-
nies, to communities or simply reserved as con-
servation areas. In order to prevent land tenure
and land use conflicts, consultative frameworks
involving all parties (loggers, mining companies,
local population, State) are sometimes estab-
lished. They are meant to ease negociations and
reach acceptable social, economic and environ-
mental compensations for all users. The princi-
ples of compensation mechanisms are integrated
in international norms and standards (PS6,
BBOP) that guide or constrain good practices in
mining activity. These norms and standards are
largely not included in national laws and regu-
lations, and could appear based on a voluntary
behaviour by the mining industry. Nevertheless,
some financial institutions grant financial
resources and lower interest rates for companies
that provide credible impact studies and imple-
ment ecological compensation policy in line with
certain international standards (Quétier et al.,
2015). The development of industrial-scale min-
ing activity being strongly dependent of access to
capital, conditional financing and requirement
of international standards could be a strong lev-
erage in setting up a social and environmental
compensation mechanism.
Direct impacts of industrial exploitation can
be relatively reduced while indirect impacts on
forests and forest-dependent communities can
be considerable. Direct impacts include defor-
estation and various pollutions of water systems,
air and soils. Other impacts result from the con-
struction of infrastructures required to transport
minerals and energy or the construction of set-
tlements required by the mining activity. Thus,
mining activity make relatively intact forest
zones accessible to populations, who not only can
hope for a job with the mining company but also
Photo 1.4 : Illustrations of impacts from artisanal mining activities
© Valery Gond
23
Figure 1.4 : Cartography of impacts in a mine in the south-east of Cameroon
Source : Gond, 2013 (Landsat 8 of 17 th december 2013)
can develop agricultural activity on new pieces
of land and excert some more pressure on fuel-
wood resources and wild fauna. The disruption
of socio-economic systems, with the rise of local
prices or the development of trafficking, are also
notable indirect impacts of mining activities that
have to be taken into account.
In summary, if deforestation needed to access
the deposit is often relatively low (Figure 1.4
and photo 1.4), degradation and deforestation
side-effects resulting from mining activity can
be serious. This can be exhacerbated in areas
where administration is absent. Many ecosystem
services provided by forests will be deteriorated
by mining. Therefore it raises an issue which is
not resolved by the scientific community : how
to make a proper assessment of the degradation
of services over the lifespan of the mining activ-
ity in relation with the financial profits derived
from the mining activity ? What kind of cost-
benefit analysis of the mining activity and other
ecoystem services can address these possible deg-
radations over the lifespan of the mine ?
As a matter of fact, few mining projects were
allowed to start in 2015 in the forests of the
Congo Basin due to financial and administrative
reasons as well as the volatility of market prices
for minerals, which have discouraged investors.
Given the current dynamics, this diagnosis could
be reviewed in a few years from now.
CMC survey
CMC camp
Mining impact?
Cam-Iron entrance
24
Besides the industrial exploitation, there is
some artisanal exploitation, mainly of gold and
diamonds, which was established in certain forest
areas long ago (albeit very scaterred and local
operations). It causes much degradation to for-
ests, perhaps to a greater extent when contrasted
to industrial mining, said obervers in the field.
In the mining sector, the hope for quick profits
is attractive and causes illegal artisanal activities
which are usually practiced by the poorest popu-
lations (Hammond etal., 2007). These artisanal
mining activities are carried out under very poor
working conditions and thus open the door to
the degradation of social and sanitary conditions.
At present there is little documentation on
small mining exploitation and no study cover for-
est areas in Central Africa while these activities
can cause, just as it happens in the Amazonian
forest basin, many environmental degradations
and serious polutions of rivers due to inappropri-
ate techniques (Gond andBrognoli, 2005).
3.3 Logging, and planned and un-planned degradation
In the Congo Basin countries, timber exploi-
tation is usually allowed through exploitation
permits. Beyond a certain size, logging compa-
nies holding such permits must have manage-
ment plans in order to sustainably manage the
forest resource. Albeit this type of exploitation
can cause some local degradation of the forest
cover, it cannot be considered as a major driver
of deforestation in itself because of low logging
rates, targeting a few species of high commercial
value (Desclée etal., 2014).
By extrapolating findings from on-going
studies in DRC (FOR AFAMA and Carbon Map
and Model), one estimates that 7 % of the for-
est is degraded due to road network, 0.5 % is
degraded by annual falling activities (one year
out of 30 when rotation is set to be 30 years).
Besides, forest cover regeneration, dissemination
of Reduced Impact Logging3 (RIL) techniques
and the development of legal or sustainable cer-
tification schemes in certain concessions, favour
limited direct forest degradation in areas logged
to produce timber. However, some indirect
impact of forest operations (such as the opening
of roads to new settlements or agricultural activi-
ties, the development of hunting activities…) can
be rather important and need to be addressed by
the companies as well.
In short, 49 million hectares of forests have
been allocated as forest concessions in the Congo
Basin. If those concessions should be sustain-
ably managed on the basis of management plans,
they are not under the threat of deforestation but
remain under the threat of forest degradation.
The impacts of timber exploitation can neverthe-
less be partly alleviated over the rotation period
(25 to 30 years) if natural or facilitated regen-
eration is allowed. However, one must admit
that the bulk of forest exploitation in the Congo
Basin countries is not conducted according to
management plans as of today. In the whole
region, 40 % of concessions are under manage-
ment plans but it is necessary to reach 100 % in
the medium run. Table 1.2 presents a synthesis of
progress by country of logging companies in pur-
suing sustainable forest management and legal or
sustainable certification schemes.
In obvious contrast to the trend towards
sustainable forest management, the whole for-
est is, at various levels, prone to illegal exploita-
tion which, depending on the country, can cause
some degradation or even deforestation of greater
magnitude when compared with legal exploita-
tion.
3 Reduced Impact Logging – RIL
– aims at improving forest exploi-
tation techniques, notably by
decreasing the width of primary,
secondary roads and skidding
trails and in controlling felling
direction.
Photo 1.6 : Coltan and
cassiterite are mainly
extracted by artisanal miners
(eastern DRC)
© Frédéric Sepulchre
Photo 1.5 : Industrial mining in DRC : 50 years later
© Hélène Dessard
25
Table 1.2 : Total areas of forest concessions under management and certification schemes
Forest concessions Managed concessions Certif ied concessions
Area
(ha)
Number Average area
(ha)
Area
(ha)
% (1) Area
(ha)
% (2)
Cameroon 7 058 958 111 63 594 5 071 000 72 % 2 393 061 34 %
Congo 12 600 221 51 247 063 3 504 159 28 % 2 584 813 21 %
Northern
Congo 5 822 597 14 415 900 3 504 159 60 % 2 584 813 44 %
Southern
Congo 6 777 624 37 183 179 00 % 00 %
Gabon 14 272 630 150 95 151 7 181 420 50 % 2 435 511 17 %
Equatorial
Guinea 0 0 0 0
CAR 3 058 937 11 278 085 3 058 937 10 0 % 0
DRC 12 184 130 80 152 302 00 % 828 033 7 %
Total 49 174 876 403 247 063 18 815 516 38 % 8 241 418 17 %
(1) Percentage of area of concessions - (2) FSC, OLB and TLTV certicates
Sources : WRI 2011 (Cameroon), Gally and Bayol 2013 (Congo), PAPPFG Project (Gabon), AGEDUFOR Project (DRC), ECOFORAF Project (CAR and
certication)
4. Forest types and carbon stocks
4.1 Stocks and dynamics of forest carbon
According to experts4 (Ciais etal., 2014), the
earth atmosphere contains circa. 830 Gt of car-
bon. One estimates that vegetation, soils, water
and garbages store 2,400 Gt of carbon. This stock
is small in comparison with deep oceans (37,100
Gt of carbon) and fossil fuels (1,000 Gt of carbon).
However, forests represent a major stake because
of their relatively fast carbon storage cycle (when
compared to other forms of sinks) and because of
the paramount role of anthropogenic drivers of
positive or negative changes in the forest cover.
Tropical forests can be an important source
of greenhouse gases. Emissions related to defor-
estation at a global level are estimated at circa.
1.6 Gt of carbon/annum, i.e. roughly 20 % of
global emissions of greenhouse gases. Drivers
of deforestation in the Congo Basin have been
mentioned earlier and they result in a significant
release of forest carbon into the atmosphere.
Conversely, it is feasible – if one cannot exert
total conservation of forest areas – to promote
more responsible exploitation methods ena-
bling to sustain the global carbon stock at the
scale of forest ecosystems. The regeneration of
degraded areas, reforestation or other appropriate
silvicultural practices can lead to a n increase
of the quantity of carbon stored and could
contribute to mitigate some Greenhouse
Gases (GHG) emissions from other car-
bon reservoirs (including fossil fuels) or to
mitigate activities inducing deforestation or
degradation.
Tropical forests can also evolve natu-
rally under the influence of environmental
factors. Depending on forest types, climate
change could increase the tree mortality or
alter the specific composition of these forest
types (Allen etal., 2010 ; Lewis etal., 2011).
Climate changes could threaten important
stocks of tropical forest carbon (see chapter
3 on the evolution of forests in the Congo
Basin relating to the climate). Conversely, a rise
in temperature and in atmospheric CO2 could
increase the storage ability of carbon by plants
but these plants’ properties have their limits
depending on various parameters including soil
fertility (Oren etal., 2001). But this issue of resil-
ience is central to current research works on trop-
ical forests : how will forests respond to climate
changes and what evolutions of related carbon
stocks are to expect ?
Photo 1.7 : e Umbrella tree
(Musanga cecropioides) in
the foreground, is a charac-
teristic species of young
secondary forests
© Frédéric Sepulchre
4 Figures in this paragraph are esti-
mated and have signicant vari-
ability depending on the source.
e objective is to present here
orders of magnitude rather than
precise data.
26
4.2 Current estimates of forest carbon stocks and forest types
The Congo Basin is covered by a continuous
forest which stretches from the Gulf of Guinea,
in the west, to the Rift Valley, in the east.
According to experts, forests in the sub-Saharan
Africa account for 10 to 20 % of global plant car-
bon. This forest is uneven and includes different
forest types where grow various tree species and
present specific issues in terms of exploitation
and conservation. It is possible to quantify large
sets of forest carbon stocks (given hereafter) but
actual research results don’t enable to establish
accurate correlation between the variation in
carbon quantities and forest types in the Congo
Basin. Biomass studies at the scale of the Congo
Basin are on-going (Shapiro and Saatchi, 2014)
and will complete previous analyses at a global
scale (Saatchi etal., 2011).
A typology of forests and related carbon stor-
age can be established (Figure 1.5) :
- The central zone includes a huge swampy
forest. It stretches across a long and dense river
network and is partly found on wet soils. In these
forests, the carbon stock amount to circa. 100 to
150 tons of carbon/hectare ;
- In other areas in DRC, Cameroon, Gabon
and Equatorial Guinea, it is mainly about dense
rainforest, more or less fragmented in the vicinity
of villages and along roads. Current satellite data
processing techniques allow quantifying with
increasing accuracy the degradation in these
areas : “intact” forest, fallow, plantations. These
forests, when undisturbed, may store up to 200
tons of carbon/hectare but upland forests do not
seem to excess 150 tons of carbon/hectare ;
- In the north and in the south of the Basin
(south of DRC and south of CAR), the dryier
forest types show trees of lower height and car-
bon stocks are less important, which amount to
circa. 150 tons of carbon/hectare ;
- Moving away from the centre of the basin,
patchwork forests and savannahs can store quan-
tities up to 100 tons of carbon/hectare in the
denser forest types but usually much less than
that ;
- Finally, woolands and wooded savannahs in
the north of Cameroon, in CAR and in the south
of DRC store low quantities of carbon, as low as
50 tons per hectare.
Photo 1.8 : e Ozouga
(Sacoglottis gabonensis) is a
giant of the coastal forests
Figure 1.5 : Distribution of biomass stocks of the main forest types in the Congo Basin.
Source : Saatchi etal., 2011
© Frédéric Sepulchre
Biomass T(C)/ha
27
5. Other benefit from forest than carbon
Carbon storage is not the sole ecosystem
service provided by these forests. Optimizing
carbon storage should not be detrimental to bio-
diversity, to the cost of the speading of exotic spe-
cies or without respecting some traditional uses
by local and indigenous people. The full range
of goods and services specific to each forest type
has to be taken into account and studied, prior
to defining land planning policies and strategies.
Negotiations on REDD+ within the United-
Nations Framework Convention on Climate
Change (UNFCCC), and the many variant of
this mechanism as projects on the ground, have
recently focussed on carbon in the scope of tropi-
cal forest management. However, forests offer
many functions beyond carbon sink and stor-
age or timber production, what is usually refered
to as “ecosystem services” such as production of
Non Timber Forest Products (NTFP), soil ero-
sion and siltation control, water quality or local
climate regulation, etc. These services are of par-
amount importance with regard to the subsist-
ence of certain populations and their livelihood,
and bring some diverse sources of revenue at local
and national level.
The priority currently given to economic
emergence in the sub-region5 national poli-
cies could appear at first glance as conf lict-
ing with the maintenance of the forest cover.
Nevertheless, the depletion of forest cover usu-
ally relates to soils more prone to erosion, which
may impact on the quality of water, and result
in silting of navigable waterways in certain areas,
or cause some damage to hydraulic turbines or
decrease the reservoir capacity of dams (Bernard
etal., 2009). It is thus possible that the deforesta-
tion and degradation of forests may – in the long
run – negatively impact on hydro-power produc-
tion or agricultural sector and hamper ambitions
about promoting these strategic sectors in sup-
port to development.
Besides, some level of deforestation will also
cause decrease in evapotranspiration, which is a
key phenomenon in the maintenance of a healthy
hydrologic cycle. The bulk of precipitations in the
Region comes from the Atlantic ocean monsoon
and the recycling of forest humidity (Brummett
etal., 2009). The depletion of forest cover could
impact on the climate at a local and regional
level, beyond carbon emissions contributing to
global warming (see Chapter 3).
Legal timber exploitation in the forest con-
cessions account for a significant part of the
income of States. For instance, it represents the
second economic pillar in the Republic of Congo
and accounts for 2 to 6 % of GDP depending on
the year. In the scope of forest management or
exploitation certification scheme, logging com-
panies also engage in perennial social undertak-
ings (schools, health centres, roads, jobs, etc.) in
favour of local and indigenous population. In
so doing they partly contribute to some redis-
tribution of revenue from forest exploitation. As
opposed to non renewable resources (oil, min-
erals, etc.), sustainable management of forest
resources, through the elaboration and imple-
mentation of management plans, allow for a
source of wealth for the States in the long run.
At present, forest plantations are not much
developed in the Congo Basin, notably because
of the need for major investments required to
start with planting species of high genetical
value, as well as because of the risky country
profile over rotation period (which may exceeds
ten years). Nevertheless, this part of the forestry
sector could and should develop in the next dec-
ades, and play a more prominent role both in
the national economies and national strategies
against climate change.
As a complement to forest exploitation,
an important fraction of the population in the
Congo Basin still relies on forests to sustain
their livelihood and the diversification of income
sources. The NTFP6, fuelwood, or artisanal tim-
ber significantly contribute to local subsistence as
well as to national economies in the sub-region
(Ingram etal., 2012). The twin markets of fuel-
wood and charcoal account for circa. 143 million
dollars and 300 000 jobs for Kinshasa City alone
(Schure etal., 2011). Bushmeat is a cost-effective
source of proteins to many rural households and
it is also transported over long distances and
sold on urban market places (Bowen-Jones etal.,
2002). The estimate of bushmeat consumption
ranges from 1.1 to 1.7 million tons per year in
DRC (CIFOR, 2007). Caterpillars and leaves
from Gnetum species are both an indispensable
source of oligoelements and proteins to certain
populations and very much appreciated by them,
5 Notaby Cameroon : Vision
Cameroun 2035 http ://
www.minepat.gov.cm/index.
php/en/modules-menu/doc_
download/106-vision-2035-du-
cameroun ; Democratic Repub-
lic of Congo : Document de la
Stratégie de la Croissance etde
la Réduction de la Pauvreté II
(2011) http ://www.afdb.org/
leadmin/uploads/afdb/Docu-
ments/Project-and-Operations/
RDC_-_2011-2015_-_Docu-
ment_de_stratégie_de_réduc-
tion_de_la_pauvreté.pdf ;
Republic of Congo : Document
de Stratégie pour la Crois-
sance, l’emploi et la Réduc-
tion de la Pauvreté (DSCERP
2012-2016) http ://www.afdb.
org/fr/documents/document/
congo-document-de-strategie-
pour-la-croissance-lemploi-et-
la-reduction-de-la-pauvrete-
dscerp-2012-2016-30118/
6 Some of the most common
NTFPs in the sub-region are
bushmeat, caterpillars, bush
mangoes (Irvingia spp.) or gne-
tum (Gnetum spp.).
28
which gives these products some high commer-
cial worth (Hoare, 2007). Forests in the Congo
Basin also play an important role in traditional
medicine. Ninety percents of the population in
DRC has reportedly used medicinal plants from
forests for their treatment (Ingram, 2009). Forest
ecosystems can also provide molecules useful
to developing treatments in modern medicine.
Despite the difficulty to get some estimates
about economic worth of certain products, these
sometimes fulfil an important role in the popula-
tion’s livelihood.
Forests in the Congo Basin are home to over
150 different ethnic groups (Megevand et al.,
2013). Certain places or “holy forests” are of
cultural or religious value to numerous com-
munities in Central Africa. The great diversity
of forest ecosystems includes many species such
as the forest elephant (Loxodonta cyclotis), the
forest buffalo (Syncerus caffer nanus), various
Primates or birds such as the bare-eaded rock-
fowl (Picathartes oreas). The sub-region holds
approximately 1,300 bird species, 336 amphib-
ian species and 400 reptile species ; 20,000 plant
species are recorded whose 8,000 are endemic
(Billand, 2012) and 32 “ecoregions7” have been
determined.
These ecosystems are unevenly exposed to
land conversion or to degradation, as a result
of uneven degree of pressure and because the
protected areas network has some uneven repre-
sentativity (Bodin etal., 2014 ; Table 1.3). Areas
where iconic species (bonobos, elephants, goril-
las, etc.) and certain access conditions and facili-
ties are met can enable the development of eco-
tourism activity (Wilkie and Carpenter, 1999).
These activities can generate some substantial
economic wealth : direct economic benefits from
tourism activity built up on gorilla tourism (tour
permits and other expenditure, guide wages, etc.)
in both Kahuzi-Biega and Virunga National
Parks exceeded $800,000 in 1990, before armed
conflicts forced parks to shut down (Weber,
1998).
Table 1.3 : Brief survey of protected areas found in the Congo Basin countries having rainforest areas
Country Number of protected
areas Area (ha) Proportion of national
territory(%)
Cameroon 30 3 825 024 8.1
Congo 15 3 992 422 11.7
CAR 16 7 014 500 11.3
DRC 51 26 415 737 11.3
Gabon 18 3 459 542 12.9
Equatorial Guinea 13 591 000 21.1
Total 143 45 298 225 11.1
Source : Doumenge etal., 2015
Photo 1.9 : Fuelwood collec-
tion in the countryside in
Burundi
7 « Ecoregion » : a classification
of ecosystems at a global scale
(Olson etal., 2001)
8 Garantees : Measures which are
compatibles with the preservation
of natural forests and biological
diversity, while making sure that
activities [REDD+] do not favour
some conversion of natural for-
ests but instead favour protection
and conservation of these forests
and ecosystem services, as well as
strengthening other social and
environmental benets.
An important aspect of the notion of ecosys-
tem services lies in the fact that beneficiaires from
services from an ecosystem belong to various lev-
els. A given piece of forest provides local benefits
(e.g. wood and non timber forest products) while
it also benefit the global community through
carbon sequestration or through the biodiversity
it includes. The focus given on a particular ser-
vice can impact, positively or negatively accord-
ing to case, on other services or on the economic
viability of management choices in the related
territory. This issue is illustrated by the promi-
nent attention given by carbon in global efforts
to improve forest governance, which has been
detrimental to other ecosystem services.
Taking into account the potential risks asso-
ciated with forest management practice solely
based on carbon, UNFCCC parties have enacted
a set of “garantees” that those countries claim-
ing result-based payments must “promote and
respect” (UNFCCC, 2010). These guarantees
cover various aspects related not only to risks but
also to additional benefits that REDD+ could
bring, with a special emphasis on “benefits related
to forest multiple functions and their importance
with regard to biodiversity conservation8”.
© Carlos de Wasseige
29
The thematic and cartographic analysis of
these benefits is one of the tools which enable to
address the complexity of this issue, while allow-
ing to identify the riskiest zones and the zones
suitable to synergies between combined actions
increasing the value of ecosystem services. Figure
1.6 illustrates a graphical representation of infor-
mation about carbon combined with informa-
tion on the presence of endangered species.
Albeit the analysis at regional level gives a gen-
eral idea about the various contexts in the region,
more detailed analyses are necessary to support
the conception of appropriate national and sub-
national policies.
Large zones can be characterized according
to various interests :
- pink : zones with high carbon. If it can be
proven that they are at risk of future pressure
(REDD+ scenario), they offer opportunities for
decreasing emissions from deforestation and
degradation, through conservation (effectiveness
and expansion of the protected area network) as
well as sustainable management of logging areas ;
- dark red : zones that are both rich in car-
bon and in endangerd species. Possible actions
on ecosystems must be envisaged in synergy with
conse rvation ;
- beige : zones that are low in carbon and
present low biodiversity value. They offer few
opportunities to reduce emissions from deforest-
ation. They could be suitable for actions aiming
at increasing carbon stocks such as afforestation
or forest rehabilitation or even agricultural devel-
opment ;
- green : zones with low carbon content but
including some high biodiversity value. They
could be used for afforestation although this
could jeopardize the species living there (nota-
bly in case of planting of exotic and fast growing
species).
Figure 1.6 : Spatial variation of carbon density and potential specific richness of endan-
gered species
Source : map made by UNEP-WCMC (IUCN, 2013 ; Baccini etal., 2012)
30
6. Possible future evolution of the forest cover (under
constant climate characteristics)
The elaboration of policies which would allow
both economic development and forest protec-
tion in the next few decades is a major challenge
for Central African countries. Developing a bet-
ter understanding of future anthropogenic pres-
sure is an important step in this process as well as
the impact of climate change.
The population in Central Africa is going to
increase strongly. According to forecasts from
the United Nations the population density in
the COMIFAC zone will be multiplied by 1.6 by
2030 and by 2 by 2050. DRC, where dense rain-
forest accounts for 70 % of the territory (Potapov
etal., 2012), shall become the 11th most popu-
lated country in the worl by 2050 (ONU, 2013).
Taking into account that countries in Central
Africa are lagging behind in development, their
forthcoming needs of a fast growing and increas-
ingly richer population will be considerable.
The bulk of the populace in Central Africa
will live in towns and cities : except for Burundi
and Chad, over 40 % of the population in 2030
will live in towns and cities in the countries of
the COMIFAC zone and over half of inhabitants
will be urban dwellers by 2050 (ONU, 2013).
Urbanization alters livelihood style. The share of
cereals, rice and products including wheat, oil as
well as dairy products and meat tends to become
more important in food intake of urban house-
holds. However, a radical western diet does not
always take over in Central African cities. The
impacts on forests from increasing demand for
agricultural products will depend not only on
the production areas but also on the production
modes : countries in the Congo Basin are cur-
rently lagging behind in agricultural productiv-
it y.
Most farmers cultivate less than one hectare
with very few tools and very little or no input.
Deforested areas detected through satellite
images between 2000 and 2010 in DRC aver-
aged to 1.4ha in area, which is likely to relate
to clearing for subsistence cultivation, as opposed
to Brazil or to Indonesia where commercial
agriculture is the major driver of deforestation
(Potapov etal., 2012). Most studies indicate that
yields could easily double if improved seeds, fer-
tilizers and adequate pest treatments were used
(Gockowski and Sonwa, 2011). Productivity
gains could increase production while control-
ling the expansion of farmland, knowing that
farmland expansion may goes together with
increased deforestation in the absence of strin-
gent zoning (Mosnier etal., 2014 ; Byerlee etal.,
2014). Moreover the expansion of agro-industrial
plantations is presented as a strategic priority in
many development plans in the sub-region (as
addressed earlier). The share of palm oil in the
world production of vegetable oil has more than
doubled in the last twenty years and has over-
taken soy oil production (OECD and FAO,
2013). The bulk of arable land suitable for culti-
vation are found in nine tropical countries only,
with lands with high potential mainly covering
some large areas in dense rainforests (Mosnier
andPirker, 2015). While available land suitable
to plantations in Indonesia and Malaysia is get-
ting scarcer and scarcer, international investors
show some increasing interest in the Congo
Basin where governments hope for quick positive
impacts from new plantations on employment
and economy (Hoyle and Levang, 2012).
Urbanization and growing demography usu-
ally go with an increase in demand for building
Photo 1.10 : Artisanal wood exploitation at the border of terrace (Rwanda)
© Carlos de Wasseige
31
materials and energy. While large logging com-
panies in the sub-region export the bulk of tim-
ber to Europe and China, numerous small-scale
artisanal loggers supply domestic urban markets
with local timber. This wood demand from
national and sub-regional markets is often less
sensitive to criteria of sustainable management
of forest areas as opposed to European markets
and therefore it constitutes a serious threat on the
future of forests in the Congo Basin.
As far as energy needs are concerned, several
hydro-electric plant projects are identified in
the sub-region and are under discussion. On the
one hand, these infrastructures will flood some
upstream forest land, but on the other hand some
better access to electricity could contribute to
solve the fuelwood issue which is a major driver
of ecosystem degradation within an increasing
radius around cities in Central Africa (Schure
et al., 2015). The maintenance of hydro-power
plants remains crucial in the long run : Inga I
and II dams in DRC work at 20 % of their capac-
ity only. Buying electrical appliances to substi-
tute fuelwood stoves remains difficult for many
households given their low purchasing power.
International industrials, notably mining
companies, could expand their activities in the
sub-region over the next few decades. Countries
in the Congo Basin are blessed with abundant
minerals : 80 % of coltan originate from DRC ;
major iron ore deposit have been located in
Cameroon, in Gabon, in Congo and in DRC ;
gold and diamond are exploited in CAR, in
Congo and in DRC. While many mining per-
mits were granted over the last few years, it is dif-
ficult to say how many will actually lead to some
exploitation. Since iron price has been dropping
since 2011, many projects in the Congo Basin
are being reviewed. Nevertheless, in the medium
and long run mining activity will likely increase
in the sub-region. Direct impacts on forest cover
are usually limited but indirect pressures dis-
cussed earlier can be serious.
In the scope of REDD-PAC9 project, the
CongoBIOM10 model (see Box 1.1) has been
designed to appraise impacts from increasing
food and fuelwood needs on forest cover in the
next few decades in the COMIFAC countries, as
well as CO2 emissions and threats over biodiver-
sity resulting from them (Figure 1.7).
9 www.redd-pac.org
10 e CongoBIOM model has
been adapted from GLO-
BIOM model developped at
IIASA (Havlík et al., 2011)
to the context of the Congo
Basin (Megevand etal., 2013 ;
Mosnier etal., 2014). It is an
economic model (uncomplete
balance) which computes the
evolution of both future pro-
duction and consumption of
agricultural products, forestry,
bioenergy and related land use
alteration.
Figure 1.7 : Future deforestation depends on future needs in food, in fuelwood and in energy in the CongoBIOM model
Box 1.1 : The CongoBIOM model
The economic land use model GLOBIOM (www.globiom.org) is developed at IIASA (Havlík etal., 2011) and usu-
ally works at global scale. In the scope of the REDD-PAC project, this model has been adapted to the Congo Basin
(“CONGOBIOM”) in order to better address local specificity and futures risks of deforestation related to the devel-
opment of livestock and agriculture sectors, forestry and bioenergy. The model uses a global database which has been
improved by entering national data (see www.redd-pac.org for the description of the database). In the model, land use
alteration is caused by an increase (or a decrease) in local and global needs for food, wood, and bioenergies depending
on the forecasts of population growth and economic growth done by other institutions (e.g. United Nations, FAO).
Additional needs can be met by an increase of productive lands (e.g. deforestation), by an increase in land productivity
(e.g. improvement of yields) or by an increase in imported goods. Land use alteration computed that way is combined
with biomass maps or biodiversity maps to estimate carbon emissions in the atmosphere and the risk of habitat loss for
some species.
32
In the absence of significant productivity
gains, the demand for land suitable for crop pro-
duction in the COMIFAC area would increase
by more than 8.5 million hectares between 2010
and 2030 in the case of casava, groundnut and
maize only. The region would double its produc-
tion of palm oil by 2030 as well as its exports,
albeit the increase in palm oil production would
mainly aim at meeting the local demand. In
total, it is assumed that the mean annual defor-
estation related to the expansion of agricultural
land for cultivation and livestock would increase
by 640 thousand hectares on average and per
annum between 2000 and 2010, by a bit more
than 1 million hectares per annum between 2010
and 2020, and finally by 1.5 million hectares
per annum between 2020 and 2030. It means a
total loss of 26 million hectares of forest between
2010 and 2030 in the Congo Basin, which rep-
resent circa. 10 % of the total forest cover (see
Figure 1.8 for the location of deforestation in
11 The variation of emissions
depends on biomass maps one
uses, here the Saatchi maps
has been used (Saatchi etal.,
2011). Besides more than half
of agriculture expansion will
occur on fallows or secondary
forests which could develop if
fallow cycles were long enough,
and this could reduce the level
of total emissions computed by
the model.
Figure 1.8 : Cumulative deforestation for the period 2010-2030 in Cameroon, Congo
and DRC (ndings resulting fom the CongoBIOM model)
Unit : ha per cells of 0.5 x 0.5 degrees
Cameroon, Congo and in DRC). The emissions
related to this deforestation could range from 8.8
to 13 billion tCO2 over the period 2010 – 2020,
when only accounting for carbone contained in
the above ground biomass and forest areas com-
pletely cleared11.
Moreover, results from works performed by
the IIASA show the threat on protected areas in
the Congo Basin. In the context of demographic
growth the States usually lack sufficient means
to guarantee territorial integrity and biodiver-
sity in protected areas. According to the find-
ings from the model, 4 % of forests in protected
areas could be destroyed in the next two decades
if their protection were not secured. Finally, log-
ging areas can also be useful in fighting defor-
estation. Indeed, in the absence of legal land ten-
ure status, it is assumed that an additional 280
thousand hectares of forest would be destroyed
between 2010 and 2020 and this figure would
reach 600 thousand hectares between 2020 and
2030. This would be particularly detrimental to
forests in the Republic of Congo, in Cameroon
and in CAR.
Overexploitation of logging concessions over
the first few years of operations, or the lack of
economic profitability, can – in theory – result
to the hand over of the logging area to the State.
It is thus crucial to strengthen the sustainability
of forest exploitation and in the meantime to add
value to forest products in order for logging areas
to play a role in maintaining forest cover and
biodiversity. According to this line of reasoning,
European consumers aware of legal operations
and sustainably managed forests can understand
that using tropical timber coming from well-
managed forests actually contributes to their
preservation because it gives these forests some
economic value and make them competitive vis-
à-vis other land uses in the sub-region.
A sustainably managed forest in the Congo
Basin produces continuously about 0.2 m³/ha/
year. Assuming a 25-30 year-rotation and recov-
ery rate usually used in processing units (±30 %),
any consumer buying a piece of sustainably pro-
duced timber 400 x 30 x 2 cm (0.08 m³) helps
securing economically and environmentally
0.5 hectare of forest over a period of 30 years.
Extrapolating from this calculation, France –
which imported 2.48 million m³ of tropical
timber in 2013 (Groutel, 2013) – could sustain-
ably preserve about 50 million hectares of for-
ests (FRM, 2015), i.e. a bit over the 49 million
ha
33
hectares of logging areas currently granted in
the Congo Basin ; provided that these forests are
well managed and are not subsequently assigned
to other uses (i.e. industrial agricultural planta-
tions).
On the other hand, current research on forest
and forest species tend to show that the human
impact on forests in the Congo Basin has been
rather widespread since the beginning of the
Holocene. Important remains of human activi-
ties and fires were noticed especially during two
periods, between 2500-1500 years before present
(BP) and since few hundred years ago, along the
Atlantic coast as well as further inland, in the
Sangha river interval (Morin-Rivat etal., 2014 ;
Biwole etal., 2015). It is nevertheless difficult to
assess the precise impact of past human popu-
lations independently of past climate changes
as they tended to occur simultaneously (see
also Chapter 2). The presence of some light
demanding species such as azobe (Lophira alata)
in Southern Cameroon seems to be related to
recruitment after human agriculture, a few hun-
dred years ago (Biwole etal., 2015), and forest
exploitation could enable to maintain such spe-
cies in the landscape, which tend to disappear
in undisturbed forests. But such positive effect
is also dependant on the maintenance of a mini-
mum forest structure such as in the past with
scattered small scale shifting cultivation and long
fallow periods.
6.1 Land planning management issues raised by development
Territorial stakes related to the future of
the Congo Basin forests are multiple : one has
to face needs incurred by the development of
these countries as well as the need to conserve
the integrity of the forestry ecosystems for pro-
viding ecosystem services and their role in cli-
mate change mitigation. The socio-ecosystem
analysis developed in the study “Horizon 2040”
supported by COMIFAC is an attempt to depict
territorial dynamics in the long run (Marien and
Bassaler, 2013). The approach developed in this
study puts forward the priority given to issues
such as regional and national political stabil-
ity, neo-urban demography and economic and
structural development projects (roads, naviga-
ble waterways, etc.) vis-à-vis the purely technical
aspects of the future dynamics of the forest cover.
Strengthening governance of States and their
administration to address illegal forest exploita-
tion and ecosystems degradation resulting from
other drivers of deforestation is a prerequisite to
any territorial construction. In the forestry sec-
tor, the FLEGT12 process tries to bring some
answer and could become a model able to inspire
other initiatives in the exploitation of natural
resources and spaces.
Thus, on-going economic development in the
sub-region will necessarily translate into making
choices about land allocation to various sectors
of activity, about management rules and poten-
tial compensation measures of possible impacts
of industrial projects on forests. Land tenure
conflicts, which frequently take place between
various economic sectors in Central Africa, are
coming back as a result of the priority given to
mining or certain types of agro-industries by the
States over other tenure rights of lesser immedi-
ate economic value. Table 1.4 and Figure 1.9,
related to the overlap of land utilization based on
legal titles, illustrate the complexity of territorial
dynamics.
12 Forest Law Enforcement, Gov-
ernance and Trade.
13 any kind of protected spaces,
without any distinction between
status and denomination
14 the whole group of COMIFAC
countries and not only the sum
of the ve countries given in the
table for which more data are
available
Table 1.4 : Overlap of main soil utilizations in some COMIFAC countries
Countries Overlap of mining
exploration over logging
areas (%)
Overlap of mining explo-
ration over conservation13
zones (%)
Overlap of mining
exploitation over logging
areas (%)
Overlap of mining
exploitation over conser-
vation13 zones (%)
Cameroon 44.3 25.7 1.9 0.0
Congo 43.7 16.3 0.4 0.0
Gabon 54.0 17.8 0.1 0.0
CAR 0.8 0.0 1.5 0.0
DRC 6.6 12.5 0.5 1.3
COMIFAC14 33.8 13.2 0.6 0.7
34
Besides, the issue of the carbon footprint of
extractive activities or agro-industrial plantations
is not yet raised with all its dimensions and com-
plexity. Various questions arise, such as to what
extent could the carbon balance be positive if
ecological compensation are to be implemented
by stakeholders at each phase of the exploitation
cycle in the mine/plantation ?
Land-use planning goes now beyond
the scope of the sole development issues and
meets today the stakes around climate change
mitigation and adaptation. Land planning and
exhaustive national cadasters seem to be the
most favoured solution to development planning
and to the resolution of associated problems and
conflicts. Some initiatives about land planning
schemes exist in various countries in the Congo
Basin, but they are only indicative and bear no
legal rights, being widely unknown and seldom
implemented by land use and development plan-
ners.
Photo 1.11: Food crops in densely populated areas leave little room for trees (Rwanda)
© Carlos de Wasseige
35
Figure 1.9 : Overlaying of various land uses in some COMIFAC countries
Source : www.globalforestwatch.org/map/
37
CHAPTER 2
climaTe of cenTral africa : pasT, presenT and fuTure
Maurice Tsalefac1, 5, François Hiol Hiol1, Gil Mahé2, Alain Laraque2, Denis Sonwa3, Paul Scholte4, Wilfried Pokam5, Andreas
Haensler6, Tazebe Beyene7, Fulco Ludwig8, François K. Mkankam9, Viviane Manetsa Djoufack5, Michel Ndjatsana10, Charles
Doumenge11
1University of Dschang, 2IRD, 3CIFOR, 4GIZ, 5University of Yaoundé, 6CSC, 7University of Washington, 8University of Wageningen, 9Université des Montagnes, 10Executive
Secretariat of COMIFAC, 11CIRAD
1. Introduction
Albeit some improvements, climates and
paleoclimates in Central Africa are still unsuf-
ficiently known. This uncomplete knowledge
results from the lack of local data, the disperse
networks of past and current measuring and the
very few pieces of scientific work on climate in
this region. Consequently, some uncertainty still
prevails on how these climates may evolve in
response to current climate warming. In order to
understand changes that might affect these cli-
mates, it is necessary to get some solid knowledge
about their current functionning, more specifically
the way they fit into the global climate system and
to what extent they affect climate variability and
changes in the tropical zone (Camberlin, 2007).
Few existing studies show that the Region presents
some mild interannual rainfall variability when
contrasted to other regions with similar annual
rainfalls. The spatial coherence is also particu-
larly weak. These two elements reflect some small
sensitivity to interannual major forcing of tropical
climate, notably to sea surface temperatures. One
also may predict an increase in extreme events,
disruptions in the frequency of meteorological
catastrophic events, hence hazards. Consequently,
it is necessary to understand how countries in the
region get organized with regard to climate change
challenges.
2. General climate context
Due to its geographic situation, Central
Africa confers a variety of climate types which
can be grouped into two broad types : equatorial
and tropical (Figure 2.1). Some areas of limited
extent are subjected to montane climate, such as
the Albertine Rift (towards the East of DRC) and
the Cameroon volcanic line.
Equatorial climate with four seasons stretches
up to southern Cameroon and CAR, the centre of
DRC, in Congo, in Gabon, in Equatorial Guinea
and in Sao Tomé and Principe (Mpounza and
Samba-Kimbata, 1990). Mean annual rainfall is
about 1,500 to 1,800 mm with some extremes as
high as 10,000 mm in Debundsha, in south-west
of Mount Cameroon, and south of Bioko Island
in Equatorial Guinea. The climate is warm and
humid with temperatures ranging between 22°C
and 30°C.
Photo 2.1 : Deforestation
causes climate changes at the
local level, promoting the loss
of water available through
rising temperatures, evapora-
tion and runo
© Charles Doumenge
38
Tropical climate, with two seasons, pres-
ents several sub-types : Sudanese, Sahelian and
Saharan. Sudanese, sudanese-sahelian and sahe-
lian sub-types are found in North Cameroon, the
south of Chad, the centre and north of CAR. The
southern DRC has a more temperate climate due
to an average altitude higher than other areas.
Mean annual rainfall ranges from 300 mm to
1,500 mm. Shahelo-Saharan and Saharan sub-
types only include north of Chad where the
mean annual rainfall is below 300 mm and where
maxima temperatures may reach 50°C (Godard
andTabeaud, 2009).
The equatorial and tropical climates of the
Northern hemisphere are characterized by a
dry and sunny main dry season (December to
February), while those in the Southern hemisphere,
especially to the Atlantic coast, have a cloudy dry
season cover preserving very high levels of humid-
ity (June to August). These climatic differences,
on both sides of the climatic hinge separating
the northern and southern climates, impact on
the vegetation and their importance is too often
unrecognized regarding future climate changes
(Gonmadje etal., 2012 ; Monteil etal., in prep.).
Figure 2.1 : Climate classication of West and Central Africa using the Köppen-
Geiger system15 (Peel etal., 2007). Af = equatorial/humid, Am = tropical/monsoon,
Aw= tropical/dry winter, BSh = semi-arid/dry, hot, BWh = arid/ hot, Cwa = hot
temperate/dry winter/hot summer, and Cwb = hot temperate/dry winter/warm
summer.
15 Note : is map is a very general
outline that reects only par-
tially the variability of climates
in Central Africa. In particular,
most of Gabon and Congo
benets from equatorial to sub-
equatorial climates, intermedi-
ate between the climates Af, Am
and Aw.
3. General functionning and characteristics of present
climates
3.1 Dynamic of the atmosphere
Two circulation modes – the Hadley circu-
lation and the Walker circulation – control the
movements of air masses and climate in Central
Africa.
3.1.1 The circulation of Hadley
The circulation named after Hadley (Figure
2.2), between the equator and the tropical lati-
tudes (30°), commands weather types and climates
in Central Africa.
The high temperatures in the equator lead to
significant evapotranspiration and the formation
of clouds causing heavy rainfall. While rising in
the atmosphere, the air becomes progressively drier
towards higher altitudes. It then moves north and
south and, when cool enough, descends to the
lower layers of the atmosphere (Figure 2.2). Strong
updrafts winds at the equator make the effect of a
pump which then attracts surface winds of tropical
latitudes towards the equator. The south and north
trade winds meet along a surface of discontinuity
called Inter-Tropical Convergence Zone (ITCZ)
or Inter-Tropical Front (ITF). The ITCZ migrates
north from January to July and allows the south-
ern trade winds, that change direction and load
oceanic moisture, to dump heavy rains on the
African continent. At its migration peak towards
39
Figure 2.2 : Section of Hadley cells on both sides of the equator (adapted from Demangeot, 1992)
north, the southern trade wind is very close to the
continent and causes the dry season from July to
August in areas located in the southern part of the
region. Starting in July, the trade winds from the
north-east, also called Harmattan, deploy itself
to the South thanks to the retreat of the ITCZ.
It reaches its southernmost position in January,
providing dry weather corresponding to the dry
season in northern Central Africa.
Figure 2.3 shows the ITCZ average positions
and the Interoceanic Convergence (IOC) on
Africa during the year. The IOC is materializing
the confluence of winds from the Atlantic and the
Indian oceans. Although the impact of the IOC
movements during the year is far from negligible,
particularly in the east of the area we are concerned
with, the migrations of ITCZ are of the utmost
importance to countries impacted by them since
they allow to understand the patterns of seasons
and their variations among years. These migra-
tions are inf luenced by the earth rotation and the
rotation around the sun as well as ocean surface
temperatures. Man, through his activities (affor-
estation, deforestation, bush fires, air pollution,
etc.), may make the composition of the air masses
more complex and impacts on their movements
and raining capacity.
Photo 2.2 : Small mountains along the Atlantic coast benet from a high atmo-
spheric moisture from the ocean which favor the development of dense evergreen
forests
© Charles Doumenge
40
3.1.2 The Walker circulation
Central Africa is also subject to a cell circula-
tion linking the climates of the entire tropical belt.
Seasonnal anomalies in regions located East and
West of the Congo Basin originate from this so
called “Walker circulation” (Figure 2.4).
Walker and Hadley circulations combine
themselves to impact seasonnal and annual cli-
matic parameters.
3.2. Impact of the ocean circulation
The ENSO phenomenon (El Niño Southern
Oscillation) seems to partly impact climates in
Central Africa as well as Sea Surface Temperatures
(SST). Rainfall variability seems to be linked to
ENSO and the western Indian Ocean in the first
months of the year, and to the Atlantic during the
June-August period ; the Indian Ocean becom-
ing again important later on (Balas etal., 2007).
Precipitations in Central Africa are promptly
and seasonnaly impacted by the behaviour of sea
surface temperatures, especialy in the Atlantic
Ocean, in relation with the dynamics of the ITCZ.
Years during which the Southern Atlantic Ocean is
warmer than usual show a lack of rainfalls during
July-September period north to 10°N latitude, and
in October-December south of Cameroon then
Gabon. Conversely, on the southern fringe of the
Figure 2.3 : Mean monthly position of the ITCZ (plain line) and the Inter-Oceanic Conuence (dash)
across Africa (Samba-Kimbata, 1991 ; Bigot, 1997).
41
Figure 2.4 :Walker circulation
Source :Dhonneur, 1985
ITCZ, a warm central Atlantic Ocean goes with
some excess of rainfalls, at least close to the ocean.
3.2.1 Space and time variability of
rainfalls at a regional scale
3.2.1.1 Mean annual rainfalls
Figure 2.5 shows the variations in rainfall
between the early twentieth and the early twenty-
first centuries (Djoufack, 2011; Djoufack and
Tsalefac, 2014). All in all, one observes two areas
of high precipitations (P>2,500 mm) : the one
above and below the equator (equator stripe) and
the coastal area of the Gulf of Guinea. Elsewhere,
total annual rainfalls do not exceed 1,500 mm.
North of 15
th
parallel, Saharan and Sahelian areas
get less than 500 mm per annum.
The bottom of the Gulf of Guinea and, in
general, the Atlantic Central Africa is under the
influence of the African monsoon and experience
heavy rainfall. This ocean influence combines
with other influences (relief, vegetation, etc.) to
create the diversity of local climates. Therefore
the high pluviometry on the coastal area from
Cameroon to Gabon is directly or indirectly
related to the presence of highlands such as Mount
Figure 2.5 : : Changes in annual rainfall (mm) between 1900 and 2000 at the regional level; a) average
1901-1950 ; b) average 1951-2002 ; c) average 1951-1970, d) average 1971-2002.
42
Cameroon or the small mountains bordering this
atlantic coast.
The Congo Basin also has its heavy rainfall,
less from the influence of the ocean than from
the evapotranspiration of its forest and marshy
cover (Bigot, 1997).
Photo 2.3 : If the climate
dries up, rare ecosystems of
high ecological value such as
the swampy clearings could
disappear
3.2.1.2 Precipitation trends
Figure 2.6 suggests that rainfalls remained rel-
atively abundant during the last century, although
they seem to have decreased since the 1950s and
especially since the 1970s. Thus, one has noticed a
downward trend of total precipitations of 31 mm/
decade between 1955 and 2006 (Aguilar etal.,
2009). The biggest fall of precipitation levels were
seen during the decade 1968 – 1980 (Mahé, 1993)
and were not of even intensity across the region.
In the south of Cameroon and in Congo, the fall
in precipitation has occurred until 1990. Besides,
in Gabon and CAR, one has observed a rise after
1980 and 1985 respectively (Mahé, 1993).
Some discrepancies were also noticed at a local
scale (Tsalefac etal., 2007 ; Tsalefac, 2013). While
the pluviometry in the north of the Republic of
Congo is marked by a fall, it remains stable in
the south of the country (Samba-Kimbata, 1991).
Similarly, one has noticed a decrease in the number
of rainy days with precipitations >1 mm, as well as
a decrease of the number of days with precipita-
tions >10 mm (Aguilar etal., 2009).
Figure 2.6 : Evolution of annual precipitations since 1950 in dierent regions of Central Africa (Mahé, 1993)
© Charles Doumenge
-1
-0.5
0
0.5
1
1950 1960 1970 1980 1990
CONGO
-1
-0.5
0
0.5
1
1950 1960 1970 1980 1990
GABON
-1
-0.5
0
0.5
1
1950 1960 1970 1980 1990
CAR
-1
-0.5
0
0.5
1
1950 1960 1970 1980 1990
CAMEROON
43
3.2.1.3 Trend in temperatures
Conversely, temperatures show an upward
trend. In the Republic of Congo, over a period
of time from 1950 until 1998, temperatures
have increased by 0.5°C up to 1°C during the
decades 1980s and 1990s (Samba-Kimbata, 1991).
Regarding changes of temperature in the long run
observed in the region, data available from local
weather stations, although limited, tend to show
some warming at a statistically significant level
(GIEC, 2007). This trend is accompanied by an
increase in extreme temperatures (for example, the
temperature of the hottest day seems to increase
by 0.25°C every new decade) while period of time
with cooler weather have become less frequent
(Aguilar etal., 2009). Nevertheless, given the
scarcity of data from field stations, it seems very
difficult to draw definitive conclusions on the
evolution of current climates.
4. Past climate of Central Africa
Paleoclimates in Central Africa are relatively
well known over the period of time spreading over
the Upper Pleistocene and Holocene for which the
chronology of climatic events has considerably
evolved, mainly due to C
14
dating. Palynology
and sedimentology studies in lakeside and sea
sediments allow a relatively coherent scheme of
paleo-climates (Table 2.1).
Around 4,000 years BP, the sea surface tem-
perature decreased and precipitation lowered. At
that time, erosion and alluvial deposits, however,
remained moderate. This phase of relative drying
changed suddenly around 2,500 years BP with a
change in the seasonal distribution of rainfall.
Despite higher sea surface temperatures and
rainfall probably more sustained than previously,
the length of the dry season seemed to increase,
causing negative effects on forest cover. At that
time, erosion and alluvial deposits intensified,
showing the existence of a more tropical climate
with contrasting seasons.
From 2,000 years BP, a wet phase resettles to
the current days, interspersed with drier periods
such as the one that took place between 500
and 200 years BP (from the XVth to the XVIIIth
century), corresponding to the small Ice Age in
Europe.
© Charles Doumenge
Table 2.1 : Overall evolution of past climates in Central Africa according to palynological and sedimentological data
Chronology Climate Indicators
-22,000 à -16,000 years BP(*)
(Kanemian) Cool and dry climate Presence of aeolian sediments and dunes along
the banks
-16,000 to -8,000-7,000 years
BP (Bossumian, Pleistocene
transition)
Humid phase Sealing of fairways and mangrove development ;
development of rainforests
-7,000 to -4,000 years BP Persistence and peak of the
humid phase
Maximum development of forests towards
-6,000 years BP and then beginning of frag-
mentation on the forest margins
-3,000 to -2,000 years BP Sudden dry phase
Sudden shrinkage and opening of forests, deep-
ening of fairways, strengthening of Benguela
Current (Giresse, 1984)
-2,000 to -1,800 years BP Sudden come back of humid
phase Expansion of forests on land not used by men
(*) BP = before present.
Photo 2.4 : Mangroves will
undoubtedly suer from
future sea level changes
44
5. Predicted climate of Central Africa
5.1. Global and regional assessments of climate changes
Assessments on how precipitation and near
surface temperature, the most important climate
parameters, might change over the course of the
21
st
century have been made by several COMIFAC
countries in the framework of their national com-
munications to the UNFCCC. These assessments
were based on projections of Global Circulation
Models (GCM) and display a limited accuracy due
to their coarse spatial resolution (up to 500 km).
As Appendix 1 shows, their projections differ
substantially between the countries.
At regional level, climate projection studies are
available that cover the Congo Basin completely or
at least to a large portion, even though the region
was not always the focus of these studies (Sonwa
etal., 2014). Most of these studies go only up to
the middle of the 21st century and use the input
of only one GCM run for one specific scenario.
But recently, a comprehensive regional climate
change assessment was conducted over the Congo
Basin region from 2010 to 2012 (CSC, 2013).
In this assessment, 77 existing and additionally
compiled global and regional climate change
projections were analyzed for high and low GHG
emission scenarios respectively. This study allowed
not only to estimate the potential magnitudes of
projected climate change signals but also enabled
to judge on the reliability of the projected changes.
Furthermore, a representative subset of the climate
change projections has been used as input for sub-
sequent impact assessments and the formulation
of adaptation options.
5.2 Near surface air temperature
The aforementioned Climate Change
Scenarios study (CSC, 2013) revealed that for
near surface air temperature all models, indepen-
dent from season and emission scenario, show a
warming of at least 1°C towards the end of the
21st century. The frequency of cold/hot days and
nights, will decrease/increase respectively, again
independently from season and emission sce-
nario (Table 2.2). Since all models are projecting
changes in the same direction, the likelihood of
these changes to occur is very high. However, the
full range of possible changes is large and mainly
caused by a few outlier model projections.
Therefore a sub range (the central 66 % of
projections) defining changes being likely to
occur was defined. For near surface annual mean
temperature the likely changes towards the end
of the century, are between +3.5°C and +6°C for
a high emission scenario and between +1.5°C and
+3°C for a low emission scenario (Haensler etal.,
2013). In general, projected temperature increase is
slightly above average in the northern parts of the
region, North of the climatic hinge, and slightly
below average in the central parts.
Table 2.2 : “Likely range” (centered on the median) of projected changes (in %) for the frequency of cold/
hot days/nights averaged over the entire Congo Basin region.
Projected Changes Low emission scenario High emission scenario
2036 – 2065 2071 – 2100 2036 – 2065 2071 – 2100
Cold nights (in %) -9 to -7 -10 to -7 -9 to -8 -10
Cold days (in %) -8 to -5 -9 to -6 -9 to -6 -10 to -9
Hot nights (in %) +27 to +43 +29 to +56 +38 to +53 +64 to +75
Hot days (in %) +12 to +21 +13 to +29 +16 to +28 +31 to +54
Source : Haensler etal. (2013).
45
5.3 Total precipitation
According to Haensler etal. (2013), for total
precipitation, the results of the different projec-
tions are not as robust as for near surface air
temperature. Some models project an increase
of annual total precipitation in most parts of
the Congo Basin region, whereas other models
project a decrease over the same areas. However,
the same authors are projecting towards the end
of the 21st century a general tendency for a slight
increase in future annual total precipitation for
most parts of the Basin. Largest increase in annual
total precipitation is projected over the generally
dryer northern part, which is mainly related to the
northward expansion of the ITCZ and to the fact
that total precipitation amounts are rather small
over this region. The range likely to occur for
changes in total annual precipitation is between
-10 to +10 % in the more humid zone and between
-15 to +30 % in the more arid zone. It thus seems
rather unlikely that drastic changes in annual total
rainfall will occur in the future.
In contrast, the rainfall characteristics are
projected to undergo some substantial changes.
The intensity of heavy rainfall events is likely to
increase in the future (likely range for most parts
positive, up to +30 %). Also the frequency of dry
spells during the rainy season is for most parts
of the domain projected to substantially increase
in the future, indicating a more sporadic rainfall
distribution.
Figure 2.7 : Projected change in annual mean temperature (left) and annual total precipitation (right)
until the end of the 21st century (2071 to 2100) for a high emission scenario.
Source : CSC (2013)
Photo 2.5 : Transport of logs
oating on the Mmi river
(Bandundu -DRC)
© Frédéric Sepulchre
in K in %
46
The depicted change in figure 2.7 is the
median change from a set of 31 different climate
change projections from global and regional cli-
mate models. The black stipples highlight regions
where the majority of the models agree in the
direction of change. Changes in these regions are
therefore more robust than over regions without
stipples.
6. Current climatic delineation and water regime trends
Abrupt climate change occurred over Africa
several decades ago with different impacts on river
regimes (Laraque etal ., 2001 ; Mahé etal., 2013).
These changes on river regimes are related both to
climate change and to human activities. Central
Africa seems much less impacted by human activi-
ties as it is the case in other African areas, due
to less population density and less agricultural
development.
In Central Africa, hydrologists have stud-
ied the hydrological regime of many rivers for
decades since the 1950s. Data are gathered in the
SIEREM information system (Boyer et al., 2006);
(http ://www.hydroscience s.org/sierem/) and in
the Hybam observatory for the Congo catchment
(http ://www.ore-hybam.org). These data are used
to study the variability of the river regimes, which
can be linked to rainfall changes.
6.1 Global trends of hydrological regimes of large watershed in Central Africa
Long time series of annual discharges standard
values for several large river basins of West and
Central Africa have been studied within large
regions (Mahé e tal ., 2013). They show differences
in the interannual variability according to the
region. Common periods of low flows and high
flows can be observed (during the 1910’s, 40’s,
60’s, 70’s). But some periods show discrepancies
in the evolution (50’s and 80’s). Equatorial rivers
do not show any interannual trend, while tropical
rivers follow a decrease since the 70’s, and Sahelian
river discharges increase since the 80’s.
6.2 Case study of the impacts of climate change on the hydrological regime of the
Congo River watershed
Beyene etal. (2013) made an assessment of
impact of projected climate change on the hydro-
logic regime and climate extremes of the Congo
River basin. This specific river basin, despite its
huge importance and implications to the regional
hydrological cycle, has the least number of climate
change impact studies in Africa to date. Land
surface hydrologic modeling, used bias-corrected
and spatially downscaled climate data from three
GCMs (CNCM3, IPSL, and ECHAM5) and two
emissions scenarios (A2-High and B1-Low), to
simulate historical and future hydrologic regimes.
The reference historical observations from the
newly available global WATCH (http ://www.
waterandclimatechange.eu/) and the forcing data-
set (henceforth referred to as WFD ; Haddeland
etal., 2011) were used to simulate the current
Photo 2.6 : Herd of cattle
entering the Faro National
Park in the dry season
(Cameroon)
© Paul Scholte
47
status of the hydrologic regime of the Congo River
basin. The current and future hydrologic regime
change in the Congo River basin was simulated
using the Variable Infiltration Capacity model
(VIC), and then assessed (Beyene etal., 2013). The
following results were found on key hydrological
parameters.
6.2.1 Evaporation
According to Beyene etal (2013) the model
simulation outcomes indicated that climate change
will result in increased evaporation throughout
the basin. The change is quite evenly distributed
throughout the basin but the increase in evapo-
ration will be slightly higher towards the edges
compared to the central Congo Basin. On aver-
age, the increase in evaporation by the end of the
century will be about 10 % for the A2 emission
scenario and 8 % for the B1 scenario (Table 2.3).
The different climate models gave similar results
and for all six scenarios the evaporation increased.
Increased evaporation as a result of climate
change is reported in many other studies, espe-
cially if the rainfall is increasing (Beyene etal.,
2013). It is important to note here that the Variable
Infiltration Capacity (VIC) modeling framework
used for this assessment does not include the direct
impact of CO
2
enrichment on plant transpira-
tion. Higher CO2 concentrations reduce plant
transpiration because the leaf stomata, through
which transpiration takes place, have to open less
in order to take up the same amount of CO2 for
photosynthesis (Lambers etal., 1998). It is thus
possible that VIC over estimates the impact of
climate change on total evapotranspiration.
Table 2.3 : Summary of changes in precipitation, evapotranspiration and runoff across the Congo River basin using climate
change scenarios (30-year average changes not weighted) for the 2050s and 2080s, for SRES A2 (high) and B1 (low) emissions
scenarios expressed as percentage change of the historical base simulation (1960 – 2000)
GCM Precipitation Evapotranspiration Runoff
A2 B1 A2 B1 A2 B1
2050 2080 2050 2080 2050 2080 2050 2080 2050 2080 2050 2080
CNCM3 +8 +12 +10 +6 +8 +11 +8 +9 +12 +15 +10 +9
ECHAM5 +6 +21 +8 +15 +13 +17 +3 +5 +16 +60 +24 +42
IPSL4 +11 +9 +5 +13 +9 +12 +9 +11 +19 +6 -3 +20
Multi-model average +8 +14 +8 +11 +10 +10 +7 +8 +15 +27 +10 +23
Source : Beyene etal. (2013).
Box 2.1 : Runoff and discharge
Runoff, in hydrology, is the quantity of water discharged in surface streams. Runoff includes not only the waters that travel over
the land surface and through channels to reach a stream but also interflow, the water that infiltrates the soil surface and travels by
means of gravity toward a stream channel (always above the main groundwater level) and eventually empties into the channel. Runoff
also includes groundwater that is discharged into a stream ; streamflow that is composed entirely of groundwater is termed base flow,
or fair-weather runoff, and it occurs where a stream channel intersects the water table (from Encyclopaedia Britannica).
Discharge, in hydrology, is the volume rate of water flow, including any suspended solids (e.g. sediment), dissolved chemicals (e.g.
CaCO3(aq)), or biologic material (e.g. diatoms), which is transported through a given cross-sectional area (from Wikipedia).
Photo 2.7 : e erosion
settles gradually on the
abandoned logging roads
© Frédéric Sepulchre
48
6.2.2 Runoff
Beyene et al. (2013) found that in most
scenarios the runoff is increasing (Table 2.3).
The increase in runoff is not evenly distributed
throughout the Basin. Runoff is especially
increasing in central and western DRC and in
the Republic of Congo. Also the Cameroon and
part of the Congo Basin shows a relatively high
increase in runoff. On the Northern, Southern and
West