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Review
Global Warming and Climate change causes, impacts and mitigation
Sivakumaran Sivaramanan*
Environmental Officer,
Environmental Impact Assessment unit, Environmental Management & Assessment division,
Central Environmental Authority,
Battaramulla, Sri Lanka.
sivaramanansr@hotmail.com September.15.2015 DOI: 10.13140/RG.2.1.4889.7128
Abstract
According to NASA and IPCC, Global temperature has increased by 1.4 oF since 1880, CO2 levels has reached 400.71
parts per billion, loss of world’s forest cover between the period 2000 and 2012 is 1.5 million square km, reduction
of land ice 287 billion metric ton per year, sea level rise is 3.2 mm per year and loss of arctic ice cover at the rate of
13.3% per decade. Increasing risk of irreversible changes due to large scale shift in the climate system such as
several sensitive species such as ocean corals, aquatic birds, reptiles such as sea turtles and amphibians are facing
extinction, failing of crops cause famine in many East African countries, decrease in potable water in
Mediterranean and Southern Africa and increasing intensity of extreme events such as forest fires (Australia and
Indonesia), flooding(Bangladesh) , storm events (tornadoes and hurricanes in USA), droughts (Sahal region) and
deadly heat waves (in India 2015) recorded in many parts of the world. Anthropogenic release of greenhouse gases
CO2, CH4, water vapour, N2O, O3, HFCs, PFCs and SF6reflects a portion of solar energy back to the earth, this
increases the temperature, causes changes in ocean currents, seasonal weather patterns and ultimately changes
the climate. Deforestation reduces the CO2 sink and it further enhances the greenhouse effect. Several mitigation
methods such as use of alternative green energy sources, reducing the use of fossil fuels, use of greenhouse gas
reduction techniques during the emission, carbon capture & carbon sequestration, afforestation, reforestation,
protection of existing forest reserves, silviculture and agroforestry are being facilitated by several international,
government and non-governmental organizations. Climate change issue can be handled either adapting to the
change or disaster risk reduction. UNDP has suggested a three step method to work on Carbon finance consist of
removal of barriers to climate friendly technologies, establishing efficient host country procedures for clean
development mechanism (CDM) and develop projects via millennium development goal (MDG) carbon facility. An
Integrated Territorial Climate Plan (ITCP) was designed for regional governments to plan their activities including
financing climate change mitigation process. This paper briefly evaluates anthropocene global climate change and
its human solutions.
Key words: Climate change, global warming, climate change mitigation, impacts of global warming,
climate change impacts, carbon capture, sequestration of carbon, climate change disasters,
Anthropocene
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Introduction
Naturally variation in solar irradiance, variations
in orbital parameters of earth and volcanic
activities cause climate change. Portion of
incoming solar energy reflects back to space.
However, a portion of such outgoing energy is
absorbed by atmospheric gases this also helps
to keep the temperature warmer (this is the
reason earth is warmer than moon) In case if
this natural heat trapping properties are not
available the average surface temperature of
the earth would be about 33oC lower (IPCC,
2001) the gases which trap the heat energy is
known as greenhouse gases. Recent decades,
after the industrial revolution the amount of
greenhouse gases (GHG) in the atmosphere has
greatly increased due to human emission of
GHG and removal of natural sinks such as
deforestation and oceanic pollution. This
process of increase in greenhouse effect causes
warming of the earth surface and alters the
energy transfer between atmosphere, space,
land and the oceans. This phenomenon is
referred as global warming. In addition, solar
energy or temperature is the driving force of
earth’s weather pattern as it drives the wind,
ocean currents, humidity pattern, movement of
clouds,etc, thus, the global climate get changed.
This also intensify the effect of natural disasters
such as storms, flooding rain, landslides,
drought, land degradation and agricultural loss,
species loss and epidemics.
Greenhouse gases give positive radiative forcing
(net increase in the energy absorption by earth)
due to increase in radiatively active natural
greenhouse gases such as CO2, CH4, water
vapour, N2O, O3. In addition HFCs, PFCs and SF6
are anthropogenic in origin and are accounted
in national greenhouse gas inventories. There
are several gases influencing the global
radiation budget such as CO, NO2, SO2 and
secondary pollutants such as tropospheric
ozone (formed in reaction with volatile organic
compounds with oxides of nitrogen under UV
radiation). Begin with industrialization burning
of fossil fuel alone causes 30% increase in the
concentration of greenhouse gases
(GHG).Earth’s surface temperature has risen by
0.18oC during last century and the projected
rise of current (21st) century is ranging between
1.1 and 6.4 oC (IPCC, 2007). In the period
ranging 1750-2001 increase in CO2 was by 31%,
150% for methane and 16% for nitrous oxide in
the atmosphere.
Are we long way from Global warming
Oblivion?
Several million years ago earth’s CO2 level was
greater than 1000 ppm and the average global
atmospheric temperature during the evaluation
of mammals and dinosaurs was about22oC
whereas today’s global average temperature is
15oC (MacRae, 2008) see figure 1. Several parts
of Arctic and Antarctica were ice free and
flourished with ancient trees and animals. Sea
level about 55 million years ago was 100m
higher than now. Norwegian Island Svalbard has
fossil evidences of massive pantodont
creatures, sequoia type trees and beasts like
crocodile were living in now frozen Svalbard. If
current increase of CO2 (mainly anthropogenic)
continues in the same level it will reach 1000
ppm by the year 2100. However, global
warming is not a new issue, it happens since
prehistoric times. Ancient warming was natural
and it was due to volcanic activities and thawing
of frozen methane alone (Adapted from Doyle,
2007).
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Figure 1: Global Temperature and CO2 levels over 600 million years (Source: MacRae, 2008)
Global warming and Climate change
Global warming and climate change refer to the
increase in average global temperatures due to
the increase in greenhouse effect by the
increase in the greenhouse gases. Natural
events such as forest fires, volcanic eruptions,
methane release from thawing of permafrost
on the ocean floor and release of methane gas
from cattle, wet lands and anthropogenic
sources of exhausts from all kinds of
combustion, industrial production of
greenhouse gases, agricultural water lodging
activities such as paddy cultivation artificial wet
lands and deforestation. Warming of the earth
causes rapid changes in pre-existing weather
pattern. According to National Oceanic and
Atmospheric Administration (NOAA) there are
several indicators those changes with the
warming world.
Factors increases with global warming
Temperature of land
Sea surface temperature
Troposphere temperature
Temperature over oceans
Ocean heat content
Sea level
Humidity
Factors decreases with global warming
o Glaciers
o Snow cover
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o Sea ice
Greenhouse effect
Weather and climate of the earth is driven by
the sun’s energy. Solar radiation heats the earth
surface, and in turn earth radiates the energy
back into space. Some gasses of the
atmosphere traps some of the outgoing energy
and retains heat. This causes to an increase in
the global temperature and also causes
subsequent changes in the weather pattern.
Gases which trap the heat energy are known as
greenhouse gases; all greenhouse gases are
positive radiative forcing agents and are
capable of disturbing the energy balance in the
atmosphere. Global warming potential (GWP)
of a gas is a measure of cumulative radiative
forcing caused by unit volume of gas over a
given period of time, GWP values for gases are
measured with reference to the GWP of the
CO2. If GWP of CO2 over a period of 100 years is
1, then GWP of methane is 34 (see table 1).
Table 1 GWP values and lifetimes
Greenhouse Gas
Lifetime
(years)
GWP time
Horizon
100 years
Methane
12.4
34
HFC-134a (hydro
fluorocarbon)
13.4
1550
CFC-11
(chlorofluorocarbon)
45.0
5350
Nitrous oxide (N2O)
121.0
298
Carbon tetra fluoride
(CF4)
50000
7350
(Source: Myhreet al., 2013)
Since 1880 Earth’s average temperature has
warmed by 0.8oC (1.4oF). This has reached a
peak in 2014 even though it is an El-nino neutral
year. The warming of earth has been increasing
more steeply during the last three decades (see
figure 2). (‘NASA,’ 2015)
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Figure2:Global temperature in the period between 1880 and 2014. (‘Anup,’2015)
According to John Cook, writing the popular
Skeptical Science blog (2010), 10 indicators of a
human finger print on global warming were
observed. They are shrinking thermosphere,
rising tropopause, less oxygen in the air, release
of 30 billion tons of CO2annually, nights
warming faster than days, more fossil fuel
carbon in coral, more heat return to earth,
more fossil fuel carbon in the air, cooling of
stratosphere and less heat escape to the space
(see figure 3).
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Figure 3:Tenindicators of a human finger print on climate change
(Source: ‘John,’ 2010 as cited in ‘Anup,’ 2015).
Throughout the history earth’s climate has
changed several times before. For the last 650,
000 years our planet has underwent several
glacial advance and retreats including
catastrophic events, these changes were
occurred due to the small variation in solar
energy received by earth during such events
and often changes the global atmospheric CO2
levels. After the last ice age (7000 years ago)
modern climatic era begins with the emergence
of human civilization. Last three decades has
shown a rapid increase in global atmospheric
CO2 levels, which never happened before (see
figure 4, 5&6).
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Figure 4: Global CO2 level throughout world’s history Source: NOAA via Shah (2015)
Figure 5:Increase in global CO2 concentrations (Source: ‘NASA Global Climate Change,’ 2015)
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Figure 6: Concentration of Main Greenhouse gases ([Etheridge et al., 1998], adjusted to the NOAA
calibration scale [Dlugokencky et al., 2005]as given in ‘James and Stephen,’ 2014).
Table 2: Major sources of Greenhouse gases
Sector
Activities
Gases
Energy
Forest fuel combustion
Natural gas leakage
Industrial activities
Biomass burning
CO2, CH4, N2O, O3
Forest
Harvesting
Clearing
Burning
CO2, CH4, N2O
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Agriculture
Paddy fields
Animal husbandry (ruminants)
Fertilizer usage
CO2, CH4, N2O
Waste management
Sanitary landfill Incineration
Biomass decay
CO2, CH4, N2O, O3, CFCs
Industrial
Metal smelting & processing
Cement production
Petrochemical production
Miscellaneous
CO2, CH4, N2O, CFCs, SF6, CF4,
C2F6
(Source: Kemp, 2004)
CO2 as greenhouse gas
Swedish chemist Svante Arrhineusis the first
person who predicted the rise of temperature
as the CO2 concentration in the atmosphere
rises his findings were published in 1896
(Hulme, 1997 as cited in Kemp, 2004). CO2
contributes for 56% of global warming, as other
geochemical cycles CO2 also used to be a self-
regulating one, until the anthropogenic vast
emission and deforestation alters the balance.
Major source of CO2is fossil fuel burning it
contributes more than75% of atmospheric CO2
in 1990s, further chemical changes during
production of lime, cement and ammonia
augment and increasing litter and garbage
decomposition are other anthropogenic means.
Natural sources such as volcanic eruption and
forest fires account for large efflux of
CO2.Increased deforestation, degradation of
oceanic algal photosynthesis due to marine
pollution also reduces the uptake of CO2from
the atmosphere, according to Dr. Michael
Gunson and Dr. Charles Miller of NASA on
Global climate change, current CO2 levels
exceeds 400 ppm (400.06 in March 2015) and
expected to reach 450 ppm or more and the
rate of increase is more than 2.75 ppm /year
(‘NASA GCC,’ 2015).
Methane
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Methane naturally exists in the atmosphere
mainly from anaerobic decaying process in
natural wetlands, methane has GWP of 21 and
its radiative forcing is 11%, its rate of increase in
the atmosphere is twice the rate of CO2.
However, life span of methane is relatively
shorter than that of CO2 as it reacts with
hydroxyl radicals and produce water and CO2
(which are less potent greenhouse gases than
methane). Anthropogenic sources account for
half of its release to the atmosphere.
Agricultural activities, increased number of
cattle and pig dairy farming and non- dairy
cattle(ruminants releases methane through
their digestive process), termite concentrated
areas such as tropical grass lands and forests
releases considerable amount of methane to
the atmosphere (Crutzenet al., 1986), forest fire
events contributes a large amount of methane
efflux particularly during ENSO.Paddy
cultivation and various other cultivation
produces flooded wetlands which generate
methane during anaerobic decomposition. Coal
mining process, leakage through the pipelines
and drilling for oil are major anthropogenic
sources (Hengeveld, 1991 as cited in Kemp,
2004). Anaerobic decaying of landfill organic
wastes and piling of garbage and fertilizer are
another source of methane, venting, flaring at
oil and gas wells, enteric fermentation, biomass
burning and burning of fossil fuels are few other
anthropogenic sources. In addition, huge
amount of methane is trapped in higher latitude
permafrost and in deep ocean sediments as
methane hydrates and clathrates. With the
effect of warming permafrost is about to melt
and temperatures of oceans gradually
increases, this causes decaying of clathrates and
release of methane, such methane release are
observed in pacific ocean floor and Siberian
permafrost (Ruddiman, 2001). Hydroxyl
reduction of methane also minimized due to the
reactions with other pollutants such as CO
(‘NASA GISS Institute on Climate and Planet,’
2010).Emission from natural sources alone
account for ~180-380 Tg per year. Current total
methane emission has risen to~450-500 Tg per
year which is twice the amount of pre-industrial
times.
Nitrous oxide
It is the third highest greenhouse gas. N2O has
the varying growth rate of 0.1–0.7 % per year
(Saikawaet al., 2014) GWP of N2O is 298 and it
accounts for 6% of total radiative forcing by
greenhouse gases (IPCC, 2001as cited in Kemp,
2004). N2O released from fertilizers mainly
during the intermittent stages of nitrification
and denitrification, breakdown of nitrogen from
livestock manure and urine account for 5% of
global efflux. Transportation is another major
source, supersonic engines and rockets releases
of N2O. Nitrous oxide is released as a byproduct
during industrial production of nitric acid mainly
in the production of inorganic fertilizer and
adipic acid used in the production of fibers such
as nylon. (‘EPA overview of greenhouse gases,’
2015)
CFC in global warming
Halogenated carbons such as CFCs were used as
refrigerants, insulating foams, aerosol sprays.
Its GWP is 12,000 its radiative forcing is 24%
(IPCC, 2001as cited in Kemp, 2004). However,
use and production of CFC is completely banned
by Montreal protocol thus current levels of
global CFC in the atmosphere are declining.
Effects of global warming
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Sea level rise
This is caused by two factors such as addition of
water from melting ice land and expansion of
sea waters as it warms. Rate of increase in sea
level is 3.19 mm per year (Shaftel, 2015), this
causes loss of low lying land, submergence of
island states in Indian and Pacific ocean might
disappear completely, loss of valuable habitats
and beaches e.g.: nesting beaches of sea turtles
get disappeared and this may affect the already
endangered sea turtle population (see figure 7).
Figure 7: Sea level change (Source: NASA Global Climate Change Land ice (2015)
Warming oceans
Heat is absorbed by the oceans affects the top
700 m of the sea. Since 1969 oceans shows
warming of 0.302 oF.
Shirking ice sheaths
Ice sheaths in Green land and Antarctica has
shown decline in their mass. Greenland lost
150-250 cubic km of ice per year in the period
between 2002 and 2006 and Antarctica lost
about 152 km of ice in the period of 2002 to
2005. According to the ‘NASA-GCC-Land ice’
(2015) the loss of ice mass in Antarctica is at the
rate of 147 billion metric tons of ice per year
since 2003, this is 258billion metric tons per
year in Greenland.
Declining Arctic sea ice
Snow plays a vital role to the environment by
reflecting the sunlight back this helps to reduce
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the warming, in addition, melting seasonal
snow provides fresh water for the life and
accrued soil moisture helps the growth of
vegetation. However, increase melting of ice by
global warming leads to spring time floods.
According to the satellite data amount of spring
snow cover in the northern hemisphere has
declined over the last five decades. Arctic sea
ice is declining at the rate of 13.3% per decade.
According to the satellite data, the lowest arctic
ice extent was recorded in 2012 (see figure 8).
Figure 8: Decreasing arctic sea ice (Source: ‘NASA GCC arctic sea ice,’ 2015; ‘NASA earth observatory,’
2000)
Antarctic melting and loss of ice shelf.
Antarctic ice shelves accounted for a mass loss
of1,089 trillion kilogram ice per year in the
period between2003 and 2008. Warm ocean
waters melt the ice sheet from underneath
(basal shelf melt) accounted for 55% of the ice
shelf melts, it also changes the ocean currents.
(‘Shaftel,’ 2015) see figure 9.
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Figure 9: Antarctica mass variation (Source: ‘NASA Global Climate Change Land ice,’ 2015).
Glacial retreat
Glaciers are retreating almost everywhere such
as Alps, Himalayas, Andes, Rockies, Alaska and
Africa.
Extreme events
1. Flood and landslides: Both causes large
death and injury in human population
such events are increasing with the
global climatic change in countries like
Bangladesh, Khartoum, Netherlands,
Egypt and Sudan.
2. Hurricanes and Tornadoes: ocean
temperatures increasing due to global
warming this subsequently increases
the wind speed when maximum wind
speed exceeds 74 miles per hour this is
called hurricanes in Atlantic and
typhoons in pacific. Tornadoes are
more frequent in USA and it causes
mass destruction to lives, properties
and crops (‘Union of concerned
scientists,’2006).
3. Droughts: there are four types of
droughts such as meteorological (low
precipitation), agricultural (lack of
moisture for crop growth), hydrological
(surface & ground water supply below
normal) and socioeconomic (effect in
the economy due to water scarcity)
such events are common in Sahal and
East African countries such as Ethiopia
and Sudan.
4. Forest fires: Are more common in
Australia and Indonesia during El-nino
events. Forest fires can naturally ignited
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by lightening, volcanic eruptions, spark
from rock falls and spontaneous
combustion. Anthropogenic slash and
burn agriculture and exotic / invasive
oily plants such as eucalyptus and pine
trees naturally causes fires. It has been
estimated between 1850 and 1980 90-
120 billion metric tons of CO2 was
released by forest fires (‘earth
observatory,’ n.d.). (Adapted from
McMichael, 2003).
5. Heat waves: heat waves killed more
than 2500 people in India (by June
2015). Most affected regions are
Andhra Pradesh, Telangana, Punjab,
Uttar Pradesh, Odisha and Bihar. It also
severely affected cattle and crop
production.
Ocean acidification
Ocean acidification has lowered the pH of the
ocean waters by about 0.11 units (SCOR 2009 as
cited in ‘Tech Ocean Science’, n.d.)This is due to
anthropogenic CO2 emission, amount of CO2 on
upper layer of the ocean has been increasing
by2 billion tons per year. Oceans have absorbed
1/3 of the CO2 produced by human activities
since 1800 and fossil fuel burning alone account
for half of the CO2 (Sabine et al., 2004 as cited
in ‘Tech Ocean Science’, n.d. ).
If CO2 emission levels continues unchanged, the
future CO2 levels will be high enough to lower
the pH of ocean to 7.8 by the year 2100 (Royal
Society, 2005 as cited in ‘Tech Ocean Science’,
n.d.).
Effects on Biodiversity
Increased temperatures of land and ocean
moved the habitat range of many species pole
ward or upward from their current location
such movements also accelerated by droughts
and desertification. Species with restricted
habitat requirement or sedentary (coral reefs)
or limited climatic or geographical range
(mountain top or Island habitats) are more
vulnerable to climate change. This also may
increase the net primary productivity as
atmospheric CO2 levels increases and
opportunists (weeds) win the competition.
Organisms of temperature dependent sex
determination such as sea turtles, crocodiles,
amphibians with permeable skin and eggs are
more vulnerable. Species that are already at risk
face extinction, many habitats such as wetlands,
beaches, grass lands and sea grass beds
disappear. Climatic change associated reduction
in Arctic and Antarctic ice alter seasonal
distribution, migratory pattern, nutritional and
reproductive status of marine mammals, it also
affect the plankton distribution this affect the
marine food chain and loss of a key stone
species make the entire food chain get
collapsed. Long living species such as perennial
trees slowly show evidence of climate change
and they slowly get recover. Changes in
phenology, breeding seasons, behavioural
alterations and patterns of migration (e.g. in
birds) are already observed (Adapted from
Secretariat of the conservation on biological
diversity (2003).
Effects on coral reefs:-Increasing temperature
causes coral bleaching in various parts of the
world and acidification of oceans affect the
corals regard to their formation of skeleton,
acidified waters cause difficulties in absorbing
calcium from the water which is essential for
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shell formation and it also dissolves the reefs
(‘Tech Ocean Science’, n.d.).
Health effects
Direct physiological effect by heat and cold,
high heat affects several in Indian states during
the early 2015, sun stroke killed several,
continuous exposure can causes skin damage,
eye disease, adverse effect on immune system
and skin cancer, temperature increases blood
pressure, viscosity and pulse thus increases the
death related to cardio vascular disease and
increased stress and malnutrition also adversely
affect the health.
Epidemics of water born and vector borne
diseases occur as flooding increases breeding
places of mosquito vectors and also breakage in
water pipes, septic tanks, sewers, drainage and
storm water gets leak and contamination in
portable water sources.
Water borne diseases: Diarrhea, cholera
anddysentery.
Vector borne diseases: falciparum malaria,
vivax malaria, dengue, elephantiasis, yellow
fever and west nile fever, rodent borne diseases
plaque, Lyme disease and tick born encephalitis
and hanata virus pulmonary syndrome.
(Adapted from McMichael, 2003)
Pros and cons of global warming
Disadvantages
Disruption of ocean circulation leads to
unknown changes and effects in world
climate.
Increasing sea level causes flooding in
low lying lands and evacuation
In Mediterranean climatic regions such
as Southern Europe, South Africa and
Western Australia precipitation get
reduced soil moisture levels decline and
ultimately productivity goes down.
Increase in desertification
Abrupt weather changes affect the
agriculture and results in food
shortages
Shortage of water in already water
scarce areas.
Starvation, malnutrition and increased
deaths in the areas of food shortage
More extreme weather and increased
frequency of catastrophic events such
as storms, typhoons and flooding
events.
Changes pollution and aeroallergen
levels
Increase in epidemics diarrhea, cholera,
dengue and malaria
Increased allergy and asthma rates due
to earlier blooming plants
Deaths may occur due to heat waves.
Crop failure and pest out break
Extinction of plants and animals
Loss of plant and animal habitats
Emigration increases from poor or low
lying countries to rich and wealthier
nations.
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Additional energy expenditure for
cooling and excavation of ground water
or bringing river water.
Melting of permafrost leads to
destruction of structures, landslides and
avalanches
Increased air pollution
Permanent loss of glaciers and ice
sheets.
Cultural heritage sites get destroyed
rapidly by increased extremes of
weather pattern
Acidification of oceans
Earlier drying of forests leads to
increased forest fires
Economical imbalance and increased
violence
Advantages
o Arctic, Antarctic, Siberia and other
frozen regions of the earth experience
more land for cultivation (opening of
new lands) and more plant growth in
favourable conditions.
o Northern Europe, Canada, Russia get
benefited with increased harvest such
as cereals, sugar beet, hay and
potatoes.
o More sea transportation ways opens
such as Canada’s North West passage.
o Less energy and fuel requirement for
warming up.
o Decrease in death due to freezing
o Longer the growing season could
increase the agricultural production
(Farhan, 2015)
CO2Mitigation
There are 3 basic ways suggested to lower the
greenhouse effect. Firstly, stopping or reducing
the emission of CO2 into the atmospheres by
ways such as use alternative green energy
sources or renewable energy sources,
upgrading the emission standards of the engine.
Secondly, liquefying the CO2 produced in the
combustion and dump into the oceans, though
it is a permanent disposal but it will result in
ocean acidification which is currently becoming
a major threat to aquatic life, thus underground
injection or geologic sequestration and
transportation/ storage of captured carbon in
industries and power plants. Thirdly, lowering
the atmospheric CO2 levels (post emission
control) this is done by increasing the sinks such
as afforestation, reforestation and prevention
of deforestation. Annually, about 2 billion tons
of CO2 ends up in oceanic organic deposits in
sea floor.
Air quality and emission trading: US EPA has
proposed to reduce greenhouse gas emission,
reduce emission from new vehicle, reducing
vehicular pollution via telecommuting and
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series of programs conducted by US EPA to
reduce the vehicular emission.
Emission control during Beijing Olympics, during
the Olympic season 300,000 heavy emission
vehicles (mostly trucks) were put away from the
site, government encourage public transport,
rules allow only some people to drive on certain
days about 2 million vehicles are removed from
roads. Mobile data collection of CO2 and soot in
the atmosphere was done. As a result the black
presence of carbon gets down by 33% in 2008.
Methods of carbon capture in power plants
and industries
Post combustion capture (PCC)
This method involves separation of CO2 from
flues gas, solvent absorption using ammonia
such as aqueous pure amines or blends of
amines, in Alstom’s Chilled Ammonia Process
(ACAP) aqueous ammonium carbonate to
bicarbonate reaction is used.
monoethanolamine (MEA) in aqueous solution
is used to capture CO2 usually from boilers, Aker
Clean Carbon is a mobile amine based facility,
amino acid salt processes is the second
generation method, amino acid salts has high
absorption capacity than amines.
Adsorption methods are using a material where
the CO2 molecules get absorbed on to the solid
surface e.g. 3X zeolites, this is comparatively
advantages than liquid based absorption as
regeneration energy is low, since the heat
capacity of solid sorbent is lower than the
aqueous solvents.
Membranes are used to separate the CO2
selectively, since CO2 has high permeability than
any other substances in the flue gas, however, it
requires a pressure gradient for the separation;
this is achieved by pressurizing flue gas on one
side of the membrane and vacuuming the other
side (Adapted from Global CCS Institute, 2012).
Pre combustion de-carbonization
This is achieved by providing ‘synthesis gas’
(mixture of H2 and CO) for combustion where
CO2 is absorbed completely. Thus, the
combustion occurs in the absence of CO2. CO in
the synthesis gas easily gets converted into CO2
which is then captured using solvent. Here a
hydrogen rich fuel is produced that facilitate the
efficient burning in the turbine and minimizes
the CO2 emission.
Transportation of captured carbon dioxide can
be done easily by regular transportation or
shipment in a compressed cylinder (IEA
Greenhouse Gas R&D Programme, n.d.).
Carbon sequestration
Carbon sequestration is a process providing
long term storage for captured carbon from
industrial effluents, which helps to reduce the
emission of carbon to Atmosphere as CO2.
Captured compressed CO2 can be injected
underground using pipe line, suitable geological
formation for CO2 sequestration are depleted
oil & gas fields, solid, porous rock such as
sandstone, shale, dolomite, basalt, or deep coal
seams and saline formations. More precisely
one or more layers below cap rock could be the
ideal place which prevents the upward
migration of CO2 after being injected (see figure
10) (Adapted from ‘EPA CCS,’ 2015).
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Figure 10: Geographical location of carbon sequestration injection zone (Source: ‘EPA CCS,’ 2015).
NOx Mitigation
To reduce NOx methods such as selective
catalytic reduction process (SCR) which has the
NOx reduction rate up to 80% where injection of
reactive chemicals such as ammonia reacts with
NOx and convert into N2 and O2, changing air to
fuel ratio and changing the combustion
temperature. In automobile NOx reduction,
catalytic converters are used e.g. three way
catalytic converters (1. conversion of NOx into
N2 and O2, 2. conversion of CO into CO2 3.
conversion of hydrocarbons into CO2 and water)
(‘Reducing Acid Rain’ US EPA, 2012).
Absorption
It is selectively isolating the pollutant, here the
gaseous pollutant dissolved in a liquid scrubbers
are coming under this category. In flue gas
Denitrification the mixing of nitrous oxides with
water resulted with nitric acid compounds
(which is a water and soil pollutant in liquid
phase). In Selective Catalytic Reduction method
ammonia is applied to the gas steam which
reacts with the oxides of nitrogen at very high
temperature (300oC) in the presence of
catalysts such as active Vanadium pentoxide
and tungsten trioxide on a carrier of titanium
which releases nitrogen and water.
19
Electrostatic precipitator
Negative corona is most preferred in industrial
application as the industrial gases such as SO2,
CO2, and H2O have best ability to absorb free
electrons and spark over voltage is higher in
negative corona. However, negative corona
generates higher level of Ozone, thus not used
in air conditioners.
Flare and Thermo Oxidizers
Flare stacks are used for burning off the
flammable gas release generally used in
petroleum refineries, natural gas processing
plants and chemical plants, this also used to
release the pressure of the equipment, flares
are designed for short term combustion. To
avoid most hazardous methane release during
fermentation in beer factories flares are used to
burn and release in the form CO2. Ground level
flares are used in earth pits. Among thermal
oxidizers regenerative thermal oxidizers are
efficient up to 95%, the process is more
simplified by the use of catalytic thermo
oxidizers where the catalyst are used to reduce
the ignition temperature and the reaction is
employed in relatively low such as
temperatures (reduction of 600 to 200 oC) there
are ventilation air methane thermal oxidizer,
thermal recuperative oxidizer and direct fired
thermal oxidizer used for the relevant purposes
(‘Thermal oxidizer,’ 2014).
Afforestation and Reforestation
Planting a tree is generally for establishing wind
breaks, shelter belts, timber, fuel wood,
flowers, nuts, vegetables, medicinal plants and
wildlife. Maintaining or protection against
forest degradation can be successful by
planting, site preparation, tree improvement,
fertilization, uneven aged stand management,
thinning, pruning, weeding, cleaning, liberation
cutting or other appropriate silviculture
techniques, maintaining or increasing the
landscape level carbon density using forest
conservation strategies, longer forest rotations,
fire management and protecting against insect
pests (IPCC, 2007).
Most popular Afforestation and Reforestation
programs
Forest plantation in a land which does not have
any forest in last 50 years of history is
Afforestation, if it has an occurrence of forest
within last five decades then it is Reforestation.
China annually increased its forest
cover by 11,500 square miles, an area
the size of Massachusetts, according to
a report from the United Nations in
2011. China’s Great Green Wall was
designed to plant nearly 90 million
acres of new forest (Jon, 2012).
Reforestation in Korea: Between 1961
and 1995, stocked forest land went up
from 4 million ha. to 6.3 million ha.
Total timber rose from 30.8 million
cubic meters in 1954 to over 164.4
million cubic meters in 1984. By 2008,
11 billion trees had been planted about
two-thirds of South Korea is now
clothed with forest.
20
Reforestation in Tanzania: the
Kwimbare forestation project: During
the nine year period of the project’s
run, over 6.4 million trees were
planted.
Reforestation in Mexico: the Mixteca
Region: Center for Integral Small
Farmer Development in the Mixteca
reforested with 1 million trees covers
more than 1000 ha.
Reforestation in the United States: the
Appalachian Regional Reforestation
Initiative: 60 million trees have been
planted on about 87,000 acres of active
mine sites in Appalachia under ARRI’s
guidance.
Reforestation in Colombia: Gaviotas
Villagers have successfully reforested
about 20,000 acres as a result rainfall
has increased by 10%. (‘Sustainablog’,
2011).
Japan after World War II, have done
intensive reforestation from 1950-1970,
during that period professional
silviculture spread out in every
Japanese village. (Gerry, 2005)
Forestry projects under the Clean
Development Mechanism (CDM) of the Kyoto
Protocol.
General features of this mechanism are
reforestation of native forests, plantations for
timber, agro forest or multipurpose tree
plantations and healing barren lands. Kyoto
Protocol governs Land use, land use, change
and forestry (LULUCF) and modalities and
procedures for CDM. Organizations such as
International Tropical Timber Organization
(ITTO) carried out the task according to the
discussed strategies.
Role of International Tropical Timber
Organization (ITTO)
International organizations such as ITTO,
encourages conservation, sustainable
development, use and trade of forest resources.
It has 59 members represent about 80% of
tropical forests and 90% tropical timber trade
worldwide. ITTO collects analyses and circulates
data on production and trade of timber and
allocates funds since 1987. It has funded more
than 750 reforestation and afforestation
projects valued US$290 million. Donors are
mostly Japan, Switzerland and the USA.
CDM projects
Pearl River Watershed Management,
China: This project proposes to alleviate
local poverty and reduce threats to
forests by afforesting 4,000 hectares in
the Guangxi Zhuang. Project also
includes half of the Pearl river basin.
Pico Bonito Forest Restoration,
Honduras: This is a pilot project on
agroforestry to support small scale
farmers of 20 villages with in the Pico
21
Bonito National park buffer zone of
2,600 ha. Main roles of the project are
introducing agroforestry for small scale
farmers, reforestation to promote
conservation, establishment of
sustainable commercial grade
plantation.
San Nicolás Afforestation project: This
project includes both forest and
agroforestry plantation in an
abandoned pasture land of 8,730 ha. In
San Nicolás, Colombia.
(Timothy, Sarah and Sandra, 2006).
Mitigation approaches for Global warming
1. Energy:
Increase energy efficiency in engines
and boilers
Switching to low carbon fossil fuels such
as natural gas
Introducing flue gas decarbonization
and carbon sequestration
Increasing the use of nuclear energy
Increase the use of renewable energy
sources
Conserve energy during the usage
2. Industry:
Reduce greenhouse gas emission such
as methane
Reduce the material content of
manufactured goods
Switch to energy efficient technology
Transferring and sharing technology
mainly from developed to developing
countries
Recycle
3. Transport:
Improving energy efficiency of vehicles
Reducing vehicle emission
Reduce the vehicle weight and size to
maximize the performance
Changing land use patterns and life
styles to reduce transport requirements
Integrate transport policies
Promote public transport option than
personal vehicles
Promote greener vehicles such as
electric cars
4. Agriculture:
Develop new management techniques
to reduce tillage, recycling of crop
residues, mixed cropping and avoid
monoculture
Restoration of wetlands
Improve energy efficiency
Improve nutrition of ruminants and
reduce methane generation
Reduce biomass burning
Manage fertilizer use to reduce nitrous
oxide production
22
5. Forestry
Substitute burning of fuel wood for
fossil fuels
Improve energy efficiency
Reduce biomass burning
Conserve CO2 in living trees
Afforestation and reforestation
6. Government
Develop industrial land use plan to
minimize energy consumption
Planning disposal of waste material to
reduce production of methane and CO2
Provide disincentives (tax) for excess
energy consumption
Provide incentives for energy
consumption and minimizing
greenhouse gas emission such as
reduce the taxes for electric and hybrid
vehicles.
Improve energy efficient, recycling and
proper waste disposal
Source: Kemp (2014)
Emission trading
It is an administrative approach of pollution
control by giving economic incentives. Emission
trading facilitates a market where parties can
buy allowance or permits for emission of
particular pollutant or credits given for
reduction of pollutants. There are several
emission reduction projects under cap and
trade scheme, here a cap (limit) values is
defined for GHG emission.
Kyoto Protocol, 1997
This is an amendment to the U.N. Framework
convention on climate change, parties are
committed to bring down the emission of six
greenhouse gases (Carbon dioxide (CO2);
Methane (CH4); Nitrous oxide (N2O);
Hydrofluorocarbons (HFCs); Perfluorocarbons
(PFCs); and Sulphur hexafluoride (SF6)(UFCCC,
2014) or reducing their production as the listed
gases cause global warming, parties agreed to
fund research on climate change and promoting
alternative energy sources in both developed
and developing nations, it also includes several
international partnerships such as Asia- Pacific
partnership on clean development and Climate.
First commitment period was between 2008
and 2012 here 37 industrialized nations and the
European community committed to reduce
GHG emissions to an average of 5% against
1990 levels. Then Doha amendment was added
in 2012, here parties committed to reduce GHG
emissions by at least 18 % below 1990 levels in
the period from 2013 to 2020.
Conclusion
Global warming is an increasing environmental
issue, earths average temperature has warmed
by 0.8oC, Annually 30 billion tons of CO2 is being
released to the atmosphere. Carbon capturing
and sequestration methods are being widely
used to minimize the CO2 level in the
atmosphere. Clean development mechanism
(CDM) developed under Kyoto protocol
promote greenhouse gas emission reduction in
23
developing world. Integrated Territorial Climate
Plan (ITCP) implementation, making green
certification as mandatory, ensure the control
of greenhouse gases, designing appropriate cap
limits, spread the energy conserving techniques
and appropriate pollution control mitigation
strategies and increase public awareness on all
known effects of global warming, funding more
researchers and discover unopened areas of
research, exploring impacts and finding
mitigation are more importantly under
evaluation by today’s scientists, environmental
sector organizations, governments and
policymakers.
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