ArticlePDF Available

Assessing air temperature trends in Mesoamerica and their implications for the future of horticulture

Authors:

Abstract and Figures

Average air temperature variation in the period 1975-2011 was analyzed across 34 locations from a broad range of Mesoamerican countries with the view to better inform agricultural scientists of what changes to expect up to, and including, the year 2025. Such changes are likely to influence a range of constraints to agricultural and horticultural productivity and therefore ensuring such estimates are as robust as possible is critical to guide breeders, pathologists, entomologists and agronomists in the region effectively. A surprising variability in temperature trends were elicited for the region with increases ranging from the equivalent of 0 to >4oC per hundred years but these trends were not associated with either the geographical positioning of the locations with reference to the Central Cordillera nor were they associated with surface elevation which ranged across sites from 0 to around 2000 m. In Guatemala, Honduras, El Salvador, Costa Rica and Panama there were sites in each country showing both increases in average air temperature and also sites showing no apparent change over the period 1975-2011. AVRDC and CATIE are promulgating the concept of “healthy landscapes” in Mesoamerica and as such both Centers seek to ensure the greater local production and consumption of nutrient-dense fruit and vegetables which are required to play an important role in combating the pervasive malnutrition still found amongst disadvantaged populations in the region. In addition, the most common vegetable crops of the region presently have yields that are seriously impaired by viruses, diseases and insects. All of these constraints are likely to be further exacerbated by increases in air temperature by 2025. Farmers respond to these growing challenges by spraying increasing amounts of pesticides, often in excessive amounts. Thus to create a more healthy environment for farm families, with less need for spraying, and to relieve crops of the unnecessary burden of diseases and insects which are compromising their natural yield potential - much more investment will be needed into horticultural research and development extension in the region, particularly in building the capacity of regional vegetable scientists in both the public and private sectors. Lines with better heat and drought tolerance and with improved resistance to the common viruses and diseases are already available from AVRDC’s breeders and CATIE’s horticulturalists. More consistent and extensive field testing and seed production of this material at regional hotspot locations will be required to tailor these appropriately to Mesoamerican countries. The means to make such improved seed widely available from local sources to poor farming communities across the region must also be a first priority as current imported seed is both expensive and often ill-adapted.
Content may be subject to copyright.
Volume 81 | Issue 2 | April 2016 63
Eur. J. Hortic. Sci. 81(2), 63–77 | ISSN 1611-4426 print, 1611-4434 online | http://dx.doi.org/10.17660/eJHS.2016/81.2.1 | © ISHS 2016
Assessing air temperature trends in Mesoamerica and their
implications for the future of horticulture
J.D.H. Keatinge1, P. Imbach2, D.R. Ledesma1, J. d’A. Hughes1, F.J.D. Keatinge3, J. Nienhuis4, P. Hanson1,
A.W. Ebert1 and S. Kumar1
1 AVRDC – The World Vegetable Center, Shanhua, Tainan, Taiwan
2 CATIE (Tropical Agricultural Research and Higher Education Center), Climate Change Program, Turrialba, Cartago, Costa Rica
3 Department of Geography, University of Florida, Gainesville, FL, USA
4 College of Agricultural and Life Sciences, University of Wisconsin, Madison, WI, USA
Original article German Society for
Horticultural Science
Introduction
Mesoamerica in its widest sense is a geographical and
cultural region extending approximately from central Mexico
to northern Colombia and including Belize, Guatemala, El Sal-
vador, Honduras, Nicaragua, Costa Rica and Panama. In Latin
America, it is one of the two regions where poverty contin-

Summary
Average air temperature variation in the period
1975–2011 was analyzed across 34 locations from a
broad range of Mesoamerican countries with the view
to better inform agricultural scientists of what changes
to expect up to, and including, the year 2025. Such

to agricultural and horticultural productivity and
therefore ensuring such estimates are as robust as
possible is critical to guide breeders, pathologists,
entomologists and agronomists in the region
effectively. A surprising variability in temperature
trends were elicited for the region with increases
ranging from the equivalent of 0 to > 4°C per hundred
years but these trends were not associated with
either the geographical positioning of the locations
with reference to the Central Cordillera nor were
they associated with surface elevation which ranged
across sites from 0 to around 2,000 m. In Guatemala,
Honduras, El Salvador, Costa Rica and Panama there
were sites in each country showing both increases in
average air temperature and also sites showing no
apparent change over the period 1975–2011. AVRDC
and CATIE are promulgating the concept of ‘healthy
landscapes’ in Mesoamerica and as such both Centers
seek to ensure the greater local production and
consumption of nutrient-dense fruit and vegetables
which are required to play an important role in
combating the pervasive malnutrition still found
amongst disadvantaged populations in the region.
In addition, the most common vegetable crops of
the region presently have yields that are seriously
impaired by viruses, diseases and insects. All of
these constraints are likely to be further exacerbated
by increases in air temperature by 2025. Farmers
respond to these growing challenges by spraying
increasing amounts of pesticides, often in excessive
amounts. Thus to create a more healthy environment
for farm families, with less need for spraying, and to
relieve crops of the unnecessary burden of diseases
and insects which are compromising their natural
yield potential – much more investment will be
needed into horticultural research and development
extension in the region, particularly in building the
capacity of regional vegetable scientists in both
the public and private sectors. Lines with better
heat and drought tolerance and with improved
resistance to the common viruses and diseases are

What is already known on this subject?
In Mesoamerica relevant knowledge to this paper has
been derived essentially from studies on maize and
other non-vegetable crops. Increasing temperature
and more erratic rainfall will likely reduce vegetable

What are the new findings?
Considerable variability in annual temperature trends
between locations has been elicited; these need to
be taken into account if medium-term projections of
vegetable productivity are to be realistic.
What is the expected impact on horticulture?

pressures in vegetables substantially and these factors
must be accounted for in future breeding, agronomy
and postharvest programs in Mesoamerica.
already available from AVRDC’s breeders and CATIE’s
horticulturalists. More consistent and extensive
     
regional hotspot locations will be required to tailor
these appropriately to Mesoamerican countries. The
means to make such improved seed widely available
from local sources to poor farming communities
         
current imported seed is both expensive and often ill-
adapted.
Keywords
climate uncertainty, vegetable breeding, tomato
production, site variability
64 European Journal of Horticultural Science
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
the Andean region); the rural poor range between 20–76%,
depending on the country (Economic Commission for Latin
America and the Caribbean [ECLAC], 2012) many of which
are malnourished. Between 14–36% of the total population
is employed in the agriculture sector (ECLAC, 2012), which
has evolved through the domestication of maize (Zea mays),
beans (Phaseolus spp.), squash (Cucurbita spp.) and chili
(Capsicum spp.) and cultivation of other crops such as tomato
(Solanum lycopersicum). Central America is one of the eight
centers of origin and diversity of our domesticated crops as
postulated by Vavilov (1926). According to Zeven and De Wet
(1982), 225 domesticated plant species have their origin in
the Central American center of diversity, representing about
9% of the total number of approximately 2,500 domesticated
species reported worldwide. Genetic resources which origi-
nated in Central America and are stored in local and interna-
tional genebanks, including CATIE and AVRDC are listed in a
recent paper by Engels et al. (2006). To avoid over-complica-
    
vegetables to climate change are deliberately not addressed
in this paper which aims to be more generic. Nevertheless,
such information for globally popular vegetable species can
be obtained from the multiple publications offered at the
World Vegetable Center website (www.avrdc.org).
  
of highlands (the Central American cordillera) with both Car-
-
tains. This variation in topography makes it agro-ecologically
very diverse. High value agricultural commodities such as
coffee, fruit and vegetables play an important role in improv-
ing people’s livelihoods and in the wellbeing of many families
by increasing income and enhancing nutrition.
The international research centers, particularly AVRDC
– The World Vegetable Center and CATIE (Tropical Agricul-
tural Research and Higher Education Center), seek to make
substantive contributions to the new UN Sustainable Devel-
        
eliminating hunger and malnutrition (See www.unsdsn.org).
Collaboration between the Centers includes emphasizing
the positive role of vegetable horticulture in helping to at-
tain food and nutritional security in the region and for the
development of healthy, sustainable landscapes in currently
poor and disadvantaged areas. They promulgate the need for
individuals to consume 400 g of fruit and vegetables a day
as recommended by the World Health Organization in order
to alleviate potential micronutrient malnutrition. This ap-
proach is presently being further developed, amongst others,
by the members of the Association of Independent Research
and Development Centers for Agriculture (AIRCA) of which
both AVRDC and CATIE are founding members (Nicholls et
al., 2014).
Such an approach requires an assessment of the likely
implications of future climate uncertainty. Keatinge et al.
(2012a, 2013, 2014, 2015) have demonstrated that there
is substantial global variability in current air temperature
trends based on data from 1975–2011. Rates of increase as
high as >4°C per hundred years (Shanhua, Taiwan) to sites
where increases are intermediate (El Bataan, Mexico) or
where there is no increase at all (Ibadan, Nigeria and Coto-
nou, Benin Republic) or even where temperature changes in
that period are negative (Çorum, Turkey) have been identi-
     -
ture imply large environmental changes which need to be ac-
counted for in current planning; e.g., to ensure that vegetable
breeders and production specialists select appropriate pa-
rental material for future varieties and design new technolo-
gies which are well adapted to their future target environ-
ments rather than to actual present-day climate and weather.
This paper’s objective therefore is to try to predict the po-
tential variability in annual average air temperature, across a
broad range of sites, expected in the next 10–15 years in the
Central American region. Thus, to demonstrate, if possible,
consistent trends in order to better inform the vegetable Re-
search and Development Community, particularly breeders,
pathologists and entomologists, of likely future challenges to
production which will need to be addressed immediately by
research.
Literature review
Climate change
Hardoy and Lankao (2011) indicate that there is substan-
tive concern amongst urban planners and related decision
makers that global climate change will impact severely in the
Central American and Caribbean region. They are concerned

more vulnerable communities such as low income groups
living in high risk sites; e.g., the driest areas found in the Pa-

IPCC (Intergovernmental Panel on Climate Change) re-
ports based on the amalgamated effects of a series of com-
plex computer models suggest that average air temperatures
may be increasing in the range of 2–4°C worldwide (Folland
et al., 2001; Parry et al., 2007). However, they state that such
climate change projection, though robust at a global level, is
also characterized by substantive uncertainty at a local level,
as shown by Keatinge et al. (2014). At the majority of sites
worldwide, but not in North America, there is a predominant
trend of increasing temperatures with night temperature

is in common with the results presented by Vincent et al.
(2005) reporting for 68 locations in South America for the
period 1960–2000. These results showed that minimum air
temperatures were increasing positively but yet there were
no consistent changes in maximum air temperatures. As a re-
sult, diurnal variations in air temperature were substantively

affect the growth and development of vegetables (Keatinge
et al., 2014) as well as other crop species.
Similarly, Quintana-Gomez (1999) reported for multiple
stations in Venezuela and Colombia using very long data runs,
with some as long as 1918–1990 (e.g., Mérida in Venezuela),
that mean minimum air temperatures, but not mean maxi-

1960–1990 and there was a consistent reduction in diurnal

and the possible effects of urban heat islands (Keatinge et al.,
2013) are suggested to have contributed to this result.
 
addressed the issue of changes in extreme temperature and
precipitation events in Central America and northern South
America over the period 1961–2003. They report that tem-
perature trends are positive regionally with a large spatial
coherence. The number of warm nights has increased while
the number of cold days and nights has decreased. The peri-
od with the greater warming during the year was during the
late summer and autumn wet season. Temperature trends of
extreme events amounting to increases of 0.2–0.3°C per dec-
ade (2–3°C per hundred years) are presented with the great-
er increases being found in daily maximum air temperatures.
Volume 81 | Issue 2 | April 2016 65
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
This has resulted in an increase in diurnal temperature range
of around 0.1°C per decade (1°C per hundred years). These

who found an increasing trend in mean temperature over
forested areas during a similar period (1960–1998), particu-
larly for northern Nicaragua and Honduras, which are cor-
   
to those of Vincent et al. (2005) and Quintana-Gomez (1999)
which are reported above for South America.
Regional average precipitation, in contrast, was report-

Nevertheless, there was an indication that the number and
severity of precipitation events was increasing. Future pro-
jections of climate change show a distinctive drying signal
(increased temperature and decrease in precipitation) for
Central America (Neelin et al., 2006), particularly during
spring and summer (Biasutti et al., 2012), and with larger
magnitudes than any other tropical region (Giorgi, 2006).
Wet and dry extremes are also expected to increase across
the region (Nakaegawa et al., 2013). Imbach et al. (2012),
using complex modeling as described in the IPCC Fourth
Assessment Report (IPCC, 2005), have considered various
future temperature scenarios for the Mesoamerican region
and conclude that by the end of the century increases in tem-
perature for this region will range from more than 2°C to less
than 4°C using the period 1950–2000 as a reference data
set (Imbach et al., 2010), with higher anomalies in the south
than in the north (Hidalgo et al., 2013). In terms of precipita-
tion these authors suggest considerable regional variability
but with increasing dryness, reduced runoff and increased
severe droughts being the likely overall outcome (Imbach
et al., 2012; Hidalgo et al., 2013). They also anticipate con-
siderable variation of evapo-transpiration across the region.
As a result, substantive changes in vegetation are predicted,
which in turn will affect run-off rates, particularly where for-
ests replace grasslands.
In a detailed model-based examination of data for climate
change in Costa Rica, Karmalkar et al. (2008, 2011) suggest
that elevation may be a key discriminating factor in deter-
mining the likely future trends in air temperature; they ex-
pect some differences in trends between the Caribbean and
       
will be less affected by climate change-induced temperature
variations than the highlands. This will be particularly the
   
et al., 2011). Temperature and temperature variance is pro-
jected to increase. There is a potential concomitant reduction
in precipitation amounting to around 30% which would have
important implications for tropical montane forest ecosys-
tems. This could result in a greater negative impact on village
communities in the highlands, which are often poor and less
resilient to risk in comparison to their lowland equivalents.
Ramirez-Villegas et al. (2013), using the general circula-
tion models that will form the basis of the 2014 IPCC report,

tropical regions may not be adequate to predict crop growth.
Errors in the order of 2°C for temperature over the growing
season were found which implies that reliance on real meas-

more appropriate than a full-scale modeling approach.
The World Meteorological Organization (WMO, 2013)
reports that the global increase in average air temperature
in the period 1971–2010 was 0.17°C per decade but in the

with the much smaller increase of only 0.062°C per decade
for the substantively longer reference period 1880–2010.
Such an observation of a much lower decadal increase in av-
erage temperature can also be seen from the long data run
(1878–2011) for Rothamsted Research station in the UK pre-
sented by Keatinge et al. (2014).
In summary, it is evident that there is not yet a clear un-
derstanding of the current trends in air temperature for the

paper does not address any further climate change issues
associated with precipitation changes. This may be the sub-
ject of a further analysis but would require the acquisition of
probably longer data runs of high quality if real differences in
precipitation regimes are to become apparent.
 Tomato production and consumption in selected Central American countries*.
Year Country
Area
harvested
(ha)
Production
(t)
Yield
(t ha-1)
Tomato
food supply
(t)
Total
population
1.000)
Consumption
per capita year-1
(kg)
2000 Costa Rica 1,044 27,319 26.2 41,319 3,919
El Salvador 840 21,352 25.4 48,053 5,940
Guatemala 6,510 172,365 26.5 124,178 11,237
Honduras 4,169 46,380 11.1 38,703 6,218
Nicaragua 427 6,234 14.6 11,440 5,074
2005 Costa Rica 1,100 41,354 37.6 89,724 4,309
El Salvador 913 29,415 32.2 100,230 6,051
Guatemala 9,429 232,624 24.7 200,476 12,717
Honduras 3,743 153,252 40.9 95,529 6,879
Nicaragua 500 7,300 14.6 5,657 5,424
2009 Costa Rica 975 64,325 66.0 94,033 4,591 20.5
El Salvador 802 17,663 22.0 102,959 6,160 16.7
Guatemala 10,271 364,933 35.5 305,540 14,034 21.8
Honduras 4,498 141,731 31.5 115,334 7,450 15.5
Nicaragua 465 8,115 17.5 7,344 5,710 1.3
* Data retrieved from FAO Statistics (FAO, 2013).
66 European Journal of Horticultural Science
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
Regional vegetable production and use
The vegetable sector in the Mesoamerican region is char-
 -
ties of market access and with producers often handicapped
with limited business skills (Hellin et al., 2009). Statistical
information on the production and use of vegetables as a
-
vidual countries within the region. For example, agricultural
census data are highly imbalanced with the latest informa-
tion available ranging between 21 (Costa Rica) and 2 years
old (Panama). Tomato is thus used as an exemplar crop in
this paper and it is safe to assume this crop to be the most
common vegetable crop grown across the region. The area
grown to tomato in 2009 was lowest in Nicaragua (465 ha)
and highest in Guatemala with 10,271 ha (Table 1; FAO,
2013). Yields were quite low in most countries in 2000 and
ranged from 11 to 36 t ha-1 (Table 1).
Tomato yields are seriously constrained by vector-trans-
mitted virus diseases such as that caused by the globally im-
portant Tomato yellow leaf curl virus (TYLCV) which is trans-
Bemisia spp.). During the 2001–2010
period, a range of virus diseases in Honduras were identi-
     
(Mauricio Rivera (FHIA), pers. commun., 2013). Another ma-
jor disease reducing yield levels is bacterial wilt caused by
Ralstonia solanacearum which is often second in importance
to virus diseases, however this bacterial disease is the most
important constraint in some areas such as the Comayagua
valley of Honduras.
TYLCV pressure on tomato production was aggravated
in the late 1980s by the introduction of the Bemisia tabaci


is exacerbated by persistent, circulative transmission of the
virus worsened by continuous sowing cycles without suita-
ble crop rotation. It is also understood that warmer and drier
conditions would favor further rapid multiplication of such

Pests and diseases are often ‘managed’ by farmers with
excessive applications of pesticides and fungicides which
may be assumed to be affecting the health and safety of
both farmers and consumers. Attempts to introduce Inte-
grated Pest Management (IPM) techniques have been made
by CATIE and FHIA (Fundación Hondureña de Investigación
Agrícola, Honduran Agricultural Research Organization),
amongst others, in collaboration with partners in Hondu-
ras but the potent mixture of begomoviruses and the other
viruses infecting tomato in the region, plus heavy pressure
from bacterial wilt require effective plant resistance for IPM
measures to be rendered more effective in future (Nienhuis
et al., 2011).
In terms of consumption, El Salvador, Honduras, Costa
Rica and Guatemala are all major consumers of tomato. The
fruit are used in the form of fresh paste in the local cuisine
with elongated-saladette types being preferred in the market
(Table 1; AVRDC, 2013b). Though tomato is an indigenous
vegetable in Mesoamerica, most seed used by commercial
growers are hybrids imported from the USA, Israel, The Neth-
erlands and Italy which may, or may not be, well adapted to
the very variable local niche environments in Mesoamerica.
Popular hybrids are ‘Pony Express’, ‘Butero, ‘Silverado,
‘Retana’ and ‘Shanty’.
20
FIGURE1. Geographic locations of meteorological station data analyzed for Mesoamerica.
 Geographic locations of meteorological station data analyzed for Mesoamerica.
Volume 81 | Issue 2 | April 2016 67
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
Trials in Nicaragua with newly introduced TYLCV-resist-
ant lines which also incorporate some resistance genes from
AVRDC – The World Vegetable Center to bacterial wilt and
the blight diseases, executed by UNA (Universidad Nacional
Agraria) in partnership with the University of Wisconsin and
AVRDC at Tisma (SE of Managua near Masaya) have proven

in November 2012 and by March 2013 was heavily infested
-
lowed and stunted due to virus infection. In contrast, not
only the hybrid ‘Shanty’ but also several AVRDC improved
lines incorporating the resistance genes Ty-1, Ty-2 and Ty-3
were not compromised by TYLCV (amongst others these in-
cluded the tomato lines AVTO1004, AVTO1031, AVTO1078
and AVTO1082). Tomato lines, homozygous for Ty-3, demon-
-
arate, Guatemala in which there was infection pressure from
up to seven different begomoviruses (Garcia et al., 2008).
Yields at harvest and fruit quality were high (Nienhuis et al.,
2012). Similar trials were conducted in northern Honduras
(at Siugatepeque) and in El Salvador (at Morazán near San
Miguel and in north-western Guatemala (at Tajumulco near
Terrango). These trial sites were at a wide range of eleva-
tions from sea level to ca. 2,200 m (Tajumulco). Viruses at
all locations, except in the Guatemalan highlands, were se-
verely damaging but several AVRDC lines proved to be suit-
ably resistant in Honduras and El Salvador (e.g., AVTO1001,
AVTO1010 at Siguatepeque and AVTO1010 at Morazán;
Nienhuis et al., 2012).
Materials and methods
Long runs of average maximum and minimum monthly
air temperature data for multiple sites in Guatemala, El
Salvador, Honduras and Panama were obtained by CATIE
through their national partners. Likewise data from single
sites in Costa Rica, Honduras, Mexico and Colombia were
      
(see Acknowledgements for details). Data for further sites
in Nicaragua, Costa Rica, Belize and Colombia were obtained
(average temperature only) from http://datamarket.com/
data/set/1loo/#!display=ta. If there were minor examples of
missing data in the recent past from this data source, these
 Location and elevation of Mesoamerican meteorological stations analyzed.
Country Meteorological station Latitude Longitude Elevation (m)
Mexico CIMMYT, El Bataan 19°31’N 098°58’W 2,250
Belize PSW Goldson airport, Belize city 17°54’N 088°31’W 5
Guatemala Huehuetenango 15°19’N 091°30’W 1,872
Santa Cruz 15°02’N 091°09’W 2,017
Coban 15°28’N 090°24’W 1,360
San Jeronimo 15°03’N 090°15’W 993
Cahabon 15°34’N 089°49’W 470
Puerto Barrios 15°43’N 088°36’W 9
El Salvador Ahuachapan 13°55’N 089°51’W 705
Santa Ana 13°59’N 089°32’W 653
Guija 14°14’N 089°28’W 493
Llopango 13°42’N 089°07’W 488
San Miguel 13°26’N 088°09’W 189
La Unión 13°20’N 088°51’W 126
Honduras La Lima, Cortes 15°27’N 087°56’W 33
Germania, Francisco Morazán 14°03’N 087°13’W 996
El Zamorano University 14°01’N 087°01’W 851
Lopez Bonito, Atlántida 15°44’N 086°51’W 21
Catacamas, Olancho 14°50’N 085°52’W 380
Nicaragua MuyMuy, Matagalpa 12°28’N 086°23’W 320
AC Sandino airport, Managua 12°14’N 086°17’W 56
Jinotega 13°13’N 086°07’W 1,081
Puerto Cabezas 14°03’N 083°23’W 21
Costa Rica Juan Santamaría airport, Alajuela 09°59’N 084°12’W 921
CATIE, La Lola, Matina 10°06’N 083°23’W 40
CATIE, Turrialba 09°53’N 083°38’W 602
Panama Bajo Grande 08°51’N 082°33’W 2,175
Mata de Limón, Las Lomas 08°24’N 082°25’W 16
Martincito, Santiago 08°05’N 080°57’W 73
La Laguna, La Yeguada 08°27’N 080°51’W 640
San Juan Bautista 07°57’N 080°25’W 11
Residencial Las Américas, Tocumen 09°02’N 079°22’W 7
Colombia CIAT, Palmira 03°29’N 076°21’W 969
R. Nunez airport, Cartagena 10°45’N 075°51’W 1
European Journal of Horticultural Science
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
68
        
such as from http://www.tutiempo.net/en/climate.
Stations in each of Guatemala, El Salvador, Honduras,
Nicaragua, Costa Rica and Panama were selected to have
substantive divergence in both elevation (Karmalkar et al.,
2008) and geographic dispersion (Table 2; Figure 1). Selec-
tion criteria included the availability of continuous data runs
(1975–2011) of high quality and sites that were less prone
    
et al., 2013). In rare cases, where some months have miss-
ing data, the monthly averages of the same months from the

Canada, 2012). Data quality was assessed by examination of
the monthly data record and sites where multiple months
were missing were not included in the analysis. Additional
data sites from Belize, Nicaragua, Costa Rica and Colombia
(in which only average temperatures were available) were
also included to try to maximize the geographical coverage of
the study and its continuity across the region. In these cases
there was much less capacity to select sites with reduced ur-

light of the temperature trend diversity of mostly urban sites
presented in Keatinge et al. (2015).
At each location, annual mean maximum and minimum
air temperatures were computed based on monthly averages
per year. The mean of these two values was then used to de-
termine the annual average air temperature. At sites where

employed directly to compute the annual average.
The period 1975–2011 was chosen as the reference
time series to accord with the global study of Keatinge et al.
(2014). Selecting this reference time series, rather than any-
thing much longer or shorter is a decision of some impor-
tance, as discussed at length by Keatinge et al. (2014, 2015),
because it is possible that it captures a global warming phase
starting from around the early 1970s which possibly peaked
in the late 1990s and early 2000s. The critical nature of this
issue of what length of record should be used if predictions
 Trend analysis in annual average air temperature (°C) for Mesoamerican meteorological stations 1975–2011.
Country Meteorological station Slope Intercept R2Signicancey
Mexico CIMMYT, El Bataan 0.027 -38.381 0.39 **
Belize PSW Goldson airport, Belize city 0.026 -24.70 0.48 **
Guatemala Huehuetenango 0.026 -34.281 0.39 **
Santa Cruz -0.004 24.647 0.00 ns
Cobán 0.034 -48.005 0.40 **
San Jerónimo 0.016 -9.104 0.09 *
Cahabon 0.007 10.76 0.00 ns
Puerto Barrios 0.026 -26.665 0.33 **
El Salvador Ahuachapan 0.015 -5.972 0.21 **
Santa Ana 0.039 -52.416 0.70 **
Guija 0.037 -46.613 0.61 **
Llopango 0.03 -34.777 0.62 **
San Miguel 0.042 -54.849 0.68 **
La Unión -0.006 39.995 0.00 ns
Honduras La Lima, Cortes 0.008 11.288 0.01 ns
Germania, Francisco Morazán 0.004 15.206 0.00 ns
El Zamorano University 0.003 18.372 0.00 ns
Lopez Bonito, Atlántida 0.018 11.353 0.21 **
Catacamas, Olancho 0.010 5.27 0.05 ns
Nicaragua MuyMuy, Matagalpa 0.029 -32.28 0.46 **
AC Sandino airport, Managua 0.02 -24.44 0.44 **
Jinotega 0.031 -40.537 0.52 **
Puerto Cabezas 0.02 -13.08 0.19 **
Costa Rica Juan Santamaría airport, Alajuelaz0.023 -23.33 0.32 *
CATIE, Turrialba 0.028 -33.408 0.29 **
CATIE, La Lola, Matina 0.009 -0.015 0.04 ns
Panama Bajo Grande 0.015 -15.476 0.12 *
Mata de Limón, Las Lomas 0.013 1.067 0.13 *
Martincito, Santiago 0.018 -8.159 0.23 **
La Laguna, La Yeguada 0.016 -8.647 0.17 **
San Juan Bautista 0.012 4.919 0.12 *
Residencial Las Américas, Tocumen 0.019 -11.315 0.30 **
Colombia CIAT, Palmira, 0.024 -23.20 0.33 **
R Nunez airport, Cartagena 0.017 -5.81 0.29 **
z Data set used was 1978–2011 as the earlier three years data were rated dubious.
y ns = no signicant difference; * = signicant at the 95% level; ** = signicant at the 99% level.
Volume 81 | Issue 2 | April 2016 69
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
are to be made of future events has been further examined by
Keatinge et al. (2015) in a global analysis of sites with long
term (>100 year records).
All data sets were subjected to regression analysis using a
linear model (Statistical Analysis System [SAS] 2011). Trend
analyses for each location are presented in Tables 3–5. The

Student’s t test at the p<0.05 and p<0.01 probability levels.
Results
The data presented in Tables 3, 4 and 5 show the changes
in average, maximum and minimum air temperatures, re-
spectively, over the period 1975–2011 across all sites. Values
of R2 were highly variable ranging from 0.76 (n=37 at San
Miguel, El Salvador) to 0.00 (n=37 at Cahabon, Guatemala).
In some sites with low R2      
be inappropriate since trends before and after 1990 could
have been different if longer runs had been available. Most
sites showed some increase in average temperature with
locations such as Coban in Guatemala and Santa Ana in El
Salvador (Figure 2) being extreme examples. All four sites
       -
perature but not at extreme rates. In contrast, some sites
showed no change at all in any of the temperature variables
selected such as Santa Cruz Belanya in Guatemala, La Union
in El Salvador (Figure 3) and for average temperature at La
Lola in Costa Rica. The majority of sites analyzed in Hondu-
ras were in this category (Tables 3 and 5). There were also
several examples where sites showed increases in maximum
temperature and no change in minimum temperature such
as at La Yeguada in Panama (Figure 4) and San Jeronimo
in Guatemala. The opposite was also observed with sites in
which maximum temperatures were static and minimum
temperatures were increasing such as at Ahuachapan in El
Salvador and Las Lomas in Panama (Figure 5). In most of the
Panamanian sites, minimum temperatures increased but no
changes in maximums were detected (Tables 4 and 5). No

 4. Trend analysis in maximum air temperature (°C) for Mesoamerican meteorological stations 1975–2011.
Country Meteorological station Slope Intercept R2Signicancez
Mexico CIMMYT, El Bataan 0.028 -32.310 0.21 **
Belize PSW Goldson airport, Belize city Data not available
Guatemala Huehuetenango 0.030 -34.837 0.43 **
Santa Cruz 0.002 19.405 0.00 ns
Cobán 0.041 -57.066 0.46 **
San Jerónimo 0.018 -7.387 0.13 *
Cahabon 0.011 8.49 0.00 ns
Puerto Barrios 0.026 -21.144 0.23 **
El Salvador Ahuachapan 0.040 -48.992 0.56 **
Santa Ana 0.034 -36.512 0.54 **
Guija 0.045 -56.887 0.55 **
Llopango 0.034 -37.658 0.62 **
San Miguel 0.023 -9.759 0.21 **
La Unión -0.005 44.608 0.00 ns
Honduras La Lima, Cortes 0.002 28.073 0.00 ns
Germania, Francisco Morazán 0.028 -27.872 0.24 **
El Zamorano University 0.016 -2.707 0.10 *
Lopez Bonito, Atlántida 0.022 -13.546 0.12 *
Catacamas, Olancho 0.021 -10.943 0.05 *
MuyMuy, Matagalpa Data not available
AC Sandino airport, Managua Data not available
Jinotega Data not available
Puerto Cabezas Data not available
Costa Rica Juan Santamaria airport, Alajuela Data not available
CATIE, Turrialba 0.045 -62.346 0.25 **
CATIE, La Lola, Matina Data not available
Panama Bajo Grande 0.002 15.029 0.00 ns
Mata de Limón, Las Lomas 0.001 30.241 0.00 ns
Martincito, Santiago 0.009 13.556 0.03 ns
La Laguna, La Yeguada 0.037 -45.266 0.47 **
San Juan Bautista -0.004 39.350 0.00 ns
Residencial Las Américas, Tocumen 0.024 -15.506 0.27 **
Colombia CIAT, Palmira, 0.033 -36.67 0.33 **
R Nunez airport, Cartagena Data not available
z ns = no signicant difference; * = signicant at the 95% level; ** = signicant at the 99% level.
70 European Journal of Horticultural Science
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
which had been observed at a very few sites in the previous
global study (Keatinge et al., 2014). Increases in average air
temperature from 2012 to 2025, based on the trends record-
ed in the period 1975–2011 assuming that the linear trends
are constant, were projected (Table 6). The additional sites
selected, for which only average temperatures were avail-
able, also showed a substantial variability between locations
not dissimilar to the original sites reported above. One such
site, at Cartagena in Colombia, shows an increase of 0.24°C
by 2025. This is close to the regional average when all data
from the 34 locations are considered.
Discussion
Analysis of temperature trends
In a previous global analysis of annual average air temper-
ature, Keatinge et al. (2014) reported substantial variability
amongst locations in observed temperature increases in the
period 1975–2011. In contrast, there was some consistency
in air temperature trends at those sites in the previous study
broadly representing Mesoamerica. In the southerly extreme
case of CIAT (International Center for Tropical Agriculture)
-
age temperature, projected to add only a further 0.34°C by
2025, was detected. In the northerly extreme case at CIM-
MYT (International Wheat and Maize Improvement Center)

temperature, with a projected increase of 0.4°C by 2025, was
reported. For the intermediate Mesoamerican site (CATIE,

increase in the period 1975–2011, with a trend of 0.4°C by
2025 (Keatinge et al., 2014). When estimated for the longer
available period 1958–2011, the increase projected was very
similar at 0.3°C
Such increases to 2025 of 0.3–0.4°C were intermediate
in comparison to those recorded at AVRDC headquarters at
Shanhua in the previous published study (Keatinge et al.,
2014) which projects a 0.6°C increase in air temperature by
2025, which equates to the very rapid increase of 4.3°C per
hundred years if the 1975–2011 trend was continued. Like-
wise, the highest increase globally in this earlier study was
observed in data from another East Asian site – the NIHHS-
5. Trend analysis in minimum air temperature (°C) for Mesoamerican meteorological stations 1975–2011.
Country Meteorological station Slope Intercept R2Signicancez
Mexico CIMMYT, El Bataan 0.026 -45.471 0.025 **
Belize PSW Goldson airport, Belize city Data not available
Guatemala Huehuetenango -0.022 -34.305 0.17 **
Santa Cruz -0.01 29.547 0.00 ns
Coban 0.026 -38.813 0.20 **
San Jeronimo 0.013 -11.042 0.00 ns
Cahabon 0.003 13.42 0.00 ns
Puerto Barrios 0.027 -32.523 0.29 **
El Salvador Ahuachapan -0.009 36.853 0.03 ns
Santa Ana 0.043 -68.389 0.70 **
Guija 0.028 -36.373 0.23 **
Llopango 0.026 -31.863 0.35 **
San Miguel 0.061 -99.732 0.76 **
La Unión -0.006 35.689 0.00 ns
Honduras La Lima, Cortes 0.014 -5.397 0.12 *
Germania, Francisco Morazan 0.021 58.409 0.08 ns
El Zamorano University 0.011 39.850 0.00 ns
Lopez Bonito, Atlántida 0.015 -9.735 0.07 ns
Catacamas, Olancho - 0.001 21.319 0.00 ns
Nicaragua MuyMuy, Matagalpa Data not available
AC Sandino airport, Managua Data not available
Jinotega Data not available
Puerto Cabezas Data not available
Costa Rica Juan Santamaria airport, Alajuela Data not available
CATIE, La Lola, Matina Data not available
Panama Bajo Grande 0.028 -46.164 0.35 **
Mata de Limón, Las Lomas 0.026 -29.122 0.42 **
Martincito, Santiago 0.026 -29.944 0.38 **
La Laguna, La Yeguada -0.005 28.079 0.00 ns
San Juan Bautista 0.027 -29.602 0.43 **
Residencial Las Américas, Tocumen 0.015 -7.379 0.13 *
Colombia CIAT, Palmira 0.008 3.60 0.05 ns
R Nunez airport, Cartagena Data not available
z ns = no signicant difference; * = signicant at the 95% level; ** = signicant at the 99% level.
Volume 81 | Issue 2 | April 2016 71
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
RDA (National Institute of Horticultural and Herbal Sciences-
Rural Development Authority) at Suwon, South Korea. Much
    -
cant global cooling in the period 1975–2011.
There is a large variation in air temperature trends be-
tween the sites examined in Guatemala, Honduras, El Salva-
dor, Costa Rica and Panama (Table 6). Increases of between
0.2 and 0.4°C by 2025 are apparent for the majority of the
sites, which accords reasonably well with the three sites dis-
cussed above. However, at a minority of sites, including Guija,
San Miguel and Santa Ana (El Salvador), warming is more
extreme approaching 0.6°C, which is similar to the higher
East Asian warming rates and would thus approach, or even
exceed, an increase of 4°C per hundred years. In direct con-
trast, but similar to what was found globally by Keatinge et
al. (2014), there are also a minority of sites which show no
warming at all including Cahabon and Santa Cruz in Guatema-
la, La Union in El Salvador and La Lima, Germania, El Zamo-
rano and Catacamas in Honduras and La Lola in Costa Rica.
It is not easy to understand what may account for this
considerable difference between locations. It is unlikely
to be an elevation factor as one of the highest sites (Santa
Cruz, Guatemala) and one of the lowest (La Union, El Salva-
dor) show no change in air temperature over the measured
period. It is also not likely to be geographical positioning
with regards to the central mountain chain as Coban (Gua-
temala), with one of the higher rates of increase of 0.47°C
by 2025 using the standard trend for prediction of the pe-
riod 1975–2011, is located between Cahabon and Santa Cruz
which both show no predicted change. Likewise, San Miguel,
which shows a rapid increase in temperature, is geographi-
cally quite close to La Union (both in El Salvador) with less
than 150 m difference in altitude. Thus, it seems appropriate
to question the suggestions of the importance of altitude and
geographic location expounded by Karmalkar et al. (2008).
The conclusions of Quintana Gomez (1999) for multiple
sites in Venezuela and Colombia (1960–1990), and of Vincent
et al. (2005) for 68 locations in South America (1960–2000),
     
but with no apparent increases in maximum temperatures,
are neither supported nor rejected by this analysis. However
sites in Panama do follow the trends reported above for South
America with minimum temperatures increasing and maxi-
mum temperatures remaining largely unchanged. In Guate-
mala, El Salvador and Honduras, results are too mixed to be
 -
nal Temperature Range (DTR = Maximum minus Minimum
daily air temperature) can be a factor that seriously impacts
vegetable development, growth and quality (Madakadze and
Waramba, 2004). Future climate conditions that result in a
general decrease in DTR can also cause an increased water
  
for crop growth.
Implications for vegetable production
How can these results, which are quite diverse, be used
to help guide horticulturalists in preparing appropriate va-
rieties and production systems for the foreseeable future in
2025? This particular year (10–15 years from now) has been
selected as being roughly the time period required for a new
variety of vegetable, such as tomato, to be bred (starting in
2014), tested, released, seed bulked and distributed and ac-
cepted broadly by farmers (AVRDC, 2010). The temperature
increase projections from this study ranged from around 0 to
0.6°C (equivalent to 0 to 4°C+ per 100 years). A risk-averse
strategy therefore is to assume an increase in annual average
air temperature of around 0.25°C in the next 15 years. The ef-
fect of heat stress on the production of vegetables in general,
and tomato in particular, has been described in a recent paper
including recommendations on how to mitigate these effects
and adapt vegetable cropping systems to climate change-in-
duced stresses (De la Peña et al., 2011). Substantive variation
within existing tomato genotypes in response to heat stress,
including two genotypes emanating from AVRDC, have been
reported by Kugblenu et al. (2013) by testing their adapta-
tion to high summer temperatures in Ghana. Only a few of
these varieties were seen to be adequately heat tolerant with
one of these being from AVRDC (CLN 2318F, now known as
AVTO 0213). Other likely implications of climate change for
crop production have been reviewed by Wolfe (2013), such

changes in diurnal temperature range and severe wind speed
events, as well as potential agronomic adaptation strategies
to develop greater system resilience for horticultural pro-
ducers.
Since a lack of virus and pathogen resistance are the pre-
sent major constraints to production in crops such as tomato,
chili and sweet pepper, increasing heat will cause additional
pressure by increasing the rate or likelihood of viral strain
change (Tsai et al., 2011), increasing the multiplication rate

the potency of major pathogens (Sheu et al., 2009). Small in-
creases in air temperature can already be demonstrated to
have had substantive effects on the geographical and altitu-


the rapid appearance of new virus strains, another option
might be to develop new varieties which are resistant to
the vectors. Accessions of the wild tomato species Solanum
galapagense have been shown to offer potential as good
   
AVRDC is currently screening its S. galapagense genebank

  -
      
sources into elite cultivars. In addition, increasing tempera-
tures will require additional measures so that abiotic stress
tolerances (to drought, heat and salinity) are encapsulated in
new tomato and pepper germplasm. Rapid progress is being
made in the breeding of such traits in lines at AVRDC and fu-
ture improved material for testing in Mesoamerica will soon
have these enhanced characteristics. A similar conclusion
may also be drawn for biotic constraints with progress being
made in lines with traits showing late blight and anthracnose
(Colletotrichum spp.) resistance (AVRDC, 2012a, 2013a).
Furthermore, FHIA has undertaken trials of tomato graft-
ed on to eggplant rootstocks at FHIA’s Centro Experimental
y Demostrativo de Horticultura (CEDEH) in the Comayagua
Valley in Honduras as an agronomic measure designed to
combat bacterial wilt in a ‘hotspot’ infested location. Tomato
grafted onto AVRDC eggplant rootstocks had a much lower
mortality rate compared to tomato grafted onto other com-
mercial rootstocks and also to ungrafted controls. These re-
sults indicating good control of bacterial wilt have led to fur-
ther FHIA trials which are currently in progress in Honduras
(Lin et al., 2008; AVRDC, 2013b).
Increasing use of known ‘hotspot’ locations for plant
breeding and testing for virus and other pathogen resistance
in Mesoamerica would be a further sensible tactic for the
horticultural science network with the likelihood of warming
72 European Journal of Horticultural Science
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
in the region. AVRDC has recently employed such an action
by shifting its cucurbit breeding programs for pumpkin (Cu-
curbita spp.) and bitter gourd (Momordica charantia) from

results have been forthcoming immediately with a number
of genebank accessions showing substantive resistance to
viruses and other pathogens (AVRDC, 2013a).
If pathogens continue to be severe constraints to veg-
etable production in a warming Mesoamerica, other tactical
       

also to help overcome existing severe malnutrition. This is
      
malnutrition affects both the rural and urban populations of
all countries in the region.
It is evident from the data presented in Table 5 and Fig-
ures 2–5 that there is a much greater degree of variability in
temperature trends than was expected at the beginning of
the study. This surprising result is compounded by the fail-

-
perature trends. Thus, neither elevation nor geographic posi-
tion (either east or west of the central mountain range) seem
to have little explanatory role in the temperature trends
which were observed. Therefore, even in the face of such real
variability there is still advice which can be offered to vegeta-
ble farmers in Mesoamerica. These include potential tactical
options that can be employed to address continued climatic
uncertainty. Three such options are highlighted here.
Tactical option one would be to consider growing other
vegetable crops which would be less prone to biotic and abi-
otic constraints and which could be well adapted to many
of the niche microenvironments in the region (De la Peña et
al., 2011). AVRDC’s genebank contains 61,000+ accessions
of 438 species of tropical vegetables (AVRDC, 2013a). Thus
it is more than likely that other possible crops exist which
21
FIGURE2. Maximum (a), minimum (b) and average (c) annual air temperatures (°C) from 1975–2011 and
linear trends at Sta. Ana, El Salvador.
30
31
31
32
32
33
33
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
max temp oC
Year
Max temp oC - Sta. Ana, El Salvador 1975-2011
Y= -36.512 + 0.034X, R2=0.54, P<0.01 (n=37)
a)
17
18
19
20
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
min temp oC
Year
Min temp oC - Sta. Ana, El Salvador 1975-2011
Y= -68.389 + 0.043X, R2=0.70, P<0.01 (n=37)
b)
23
24
25
26
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
ave temp oC
Year
Ave temp oC - Sta. Ana, El Salvador 1975-2011
Y= -52.416 + 0.039X, R2=0.70, P<0.01 (n=37)
c)
22
FIGURE3. Maximum, minimum and average annual air temperatures (°C) from 1975–2011 and linear
trends at La Union, El Salvador.
33
34
35
36
37
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
max temp oC
Year
Max temp oC - La Union, El Salvador 1976-2011
Y= 44.608 - 0.005X, R2=0.00, NS (n=36)
a)
19
20
21
22
23
24
25
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
min temp oC
Year
Min temp oC - La Union, El Salvador 1976-2011
Y= 35.689 - 0.006X, R2=0.00, NS (n=36)
b)
25
26
27
28
29
30
31
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
ave temp oC
Year
Ave temp oC - La Union, El Salvador 1976-2011
Y= 39.955 - 0.006X, R2=0.00, NS (n=36)
c)
 Maximum (a), minimum (b), and average (c) an-
nual air temperatures (°C) from 1975–2011 and linear
trends at Sta. Ana, El Salvador.
 Maximum, minimum, and average annual air tem-
peratures (°C) from 1975–2011 and linear trends at La
Union, El Salvador.
Volume 81 | Issue 2 | April 2016 73
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
   
consumers based on experiences gained by AVRDC in other
tropical locations. Such crops might include highly nutrient
dense and agronomically robust species such as vegetable
soybean (Glycine max), kangkong (Ipomoea aquatica) or Af-
rican eggplants (Solanum aethiopicum, S. anguivi, and S. mac-
rocarpon).
Tactical option two would be to encourage the further
availability of small lots of diverse vegetable seeds for the
wide-scale development of home, school, hospital, prison
and related community gardens to provide rural and urban
populations with an immediate source of a wide range of
fresh vegetables. This option has been widely discussed with
extensive worldwide coverage by Keatinge et al. (2012b) and
by Galhena et al. (2013) considering that home and com-
munity gardens have been effective not only in preserving
agricultural biodiversity and increasing the production and
consumption of vegetables, but also in improving family
health and in the empowerment of disadvantaged members
of society. Seed supply can be a serious limitation but private
  
promulgated in Bangladesh by the Lal Teer (Red Arrow) seed
company for local small-scale home gardens, and the social
responsibility activities of East-West Seed with AVRDC in In-
donesia to produce seed packs for disaster relief, could easily

eastwestindo.com).
Tactical option three would be to assist small-scale grow-
ers to combat biotic production constraints by much more
extensive use of a range of protected agricultural techniques
ranging from small plastic and netting structures to larger
scale screen/plastic and glass houses. The principal objective
of such a structure would be to reduce infestation by insect
vectors, and to minimize infection by bacterial and fungal
pathogens. An additional advantage of protected structures
is to reduce the effect of heavy rains and wind on the vegeta-
23
FIGURE4. Maximum, minimum and average annual air temperatures (°C) from 1975–2011 and linear
trends at La Yeguada, Panama.
26
27
28
29
30
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
max temp oC
Year
Max temp oC - La Yeguada, Panama 1975-2011
Y= -45.266 + 0.037X, R2=0.47, P<0.01 (n=37)
a)
15
16
17
18
19
20
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
min temp oC
Year
Min temp oC - La Yeguada, Panama 1975-2011
Y= 28.079 - 0.005X, R2=0.00, NS (n=37)
b)
21
22
23
24
25
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
ave temp oC
Year
Ave temp oC La Yeguada, Panama 1975-2011
Y= -8.647 + 0.016X, R2=0.17, P<0.01 (n=37)
c)
24
FIGURE5. Maximum, minimum and average annual air temperatures (°C) from 1975–2011 and linear
trends at Las Lomas, Panama.
30
31
32
33
34
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
max temp oC
Year
Max temp oC - Las Lomas, Panama 1975-2011
Y= 30.241 + 0.001X, R2=0.00, NS (n=37)
a)
21
22
23
24
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
min temp oC
Year
Min temp oC - Las Lomas, Panama 1975-2011
Y= -29.122 + 0.026X, R2=0.42, P<0.01 (n=37)
b)
25
26
27
28
29
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
ave temp oC
Year
Ave temp oC - Las Lomas, Panama 1975-2011
Y= 1.067 + 0.013X, R2=0.13, P<0.05 (n=37)
c)
 4. Maximum, minimum, and average annual air tem-
peratures (°C) from 1975–2011 and linear trends at La
Yeguada, Panama.
 5. Maximum, minimum, and average annual air tem-
peratures (°C) from 1975–2011 and linear trends at Las
Lomas, Panama.
74 European Journal of Horticultural Science
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
 
and pepper production through the use of screen houses
would likely be a very sound investment. Farmers in the
Indian Punjab have recently begun using robust net houses
based on those found and manufactured in Taiwan, and have
seen substantive increases in crop production and quality,

2012b).
Conclusions
Since 1975 there have been many different trends in air
temperature across Mesoamerica, ranging from no predict-
able change to high rates of change exceeding 4°C per hun-
dred years. This ‘confused’ picture should not however be
an excuse for horticulturalists to take no action in response.
Given the risk that existing plant pathogen constraints may
increase in severity, greater effort must be made to ensure
that new lines incorporate suitable resistance traits to the
maximum extent possible. Likewise, the promulgation of lo-
cal or regional seed sources and supplies should be encour-
aged to ensure that Mesoamerican ‘niche’ environments for
vegetable production are appropriately serviced. Ensuring a
further strengthening of heat, drought and salinity tolerance
amongst parental germplasm over the next 20–25 years,
in accordance with the ‘median’ position suggested by this
analysis of 0.25°C by 2025 (2°C per hundred years), would
be a suitable risk averse option.
-
       
stimulated, starting with government policies supportive
   
then greater efforts are needed to counteract the misuse and
over-spraying with pesticides that endangers the health and
safety of both producers and consumers.
Local production amongst the general population, from
home, school and community vegetable gardens, that have
 6. Estimated maximum, minimum and average air temperature increases (°C) projected from 2012 to 2025 for Meso-
american meteorological stations.
Country Meteorological station Increases in
Maximum Minimum Average
Mexico CIMMYT, El Bataan 0.39 0.36 0.38
Belize FSW Goldson airport NAzNA 0.36
Guatemala Huehuetenango 0.42 0.31 0.37
Santa Cruz 0.00 0.00 0.00
Cobán 0.58 0.37 0.47
San Jerónimo 0.25 0.00 0.22
Cahabon 0.00 0.00 0.00
Puerto Barrios 0.36 0.38 0.37
El Salvador Ahuachapan 0.56 0.00 0.22
Santa Ana 0.48 0.61 0.54
Guija 0.64 0.40 0.52
Llopango 0.48 0.36 0.42
San Miguel 0.32 0.85 0.59
La Unión 0.00 0.00 0.00
Honduras La Lima, Cortes 0.00 0.19 0.00
Germania, Francisco Morazán 0.39 0.00 0.00
El Zamorano University 0.23 0.00 0.00
Lopez Bonito, Atlántida 0.30 0.00 0.26
Catacamas, Olancho 0.29 0.00 0.00
Nicaragua MuyMuy, Matagalpa NA NA 0.41
A.C. Sandino airport, Managua NA NA 0.36
Jinotega NA NA 0.43
Puerto Cabezas NA NA 0.28
Costa Rica Juan Santamaría airport, Alajuela NA NA 0.32
CATIE, Turrialba 0.63 0.00 0.39
CATIE La Lola, Matina NA NA 0.00
Panama Bajo Grande 0.00 0.40 0.21
Mata de Limón, Las Lomas 0.00 0.36 0.18
Martincito, Santiago 0.00 0.36 0.25
La Laguna, La Yeguada 0.52 0.00 0.23
San Juan Bautista 0.00 0.37 0.16
Residencial Las Américas, Tocumen 0.33 0.21 0.27
Colombia CIAT, Palmira 0.46 0.00 0.34
R. Nunez airport, Cartagena NA NA 0.24
z NA = Data not available.
Volume 81 | Issue 2 | April 2016 75
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
improved nutrition, health and development in other dis-
advantaged societies (Keatinge et al., 2012b), should be en-
couraged. Likewise, increased species diversity of vegetables
in the horticultural systems of the region would be a positive
development and would help increase the resilience of pro-
ducers in the face of the inevitable biotic and abiotic stresses
common in this type of agriculture and which will be exac-
erbated by the climate uncertainty predicted by this study.
Acknowledgments
CATIE and AVRDC wish to thank:
INSIVUMEH (National Seismology, Vulcanology,
Meteorology and Hydrology Institute), Claudio Castañoñ
and Rosario Gómez for data from Guatemala;
The Environmental Observatory of MARN (Environment
and Natural Resources Ministry) and Ana Daisy López for
data from El Salvador;
The Meteorological Analysis Unit from ETESA (Electrical
Transmission Company) and Ambrosio Morales for data
from Panama;
Alexander Salas for data from Costa Rica;
Dr. Bruno Rapidel for data from Honduras;
For data for El Zamorano University in Honduras: Ing.
Francisco Alvarez;
For data for CIAT Palmira, Colombia: Dr. Andres Palau;
For data for CIMMYT El Bataan, Mexico: Dr. Kai Sonder;
For data from Nicaragua: Isolina Gutiérrez Aguilar of the
National Meteorological Service.
The authors would also like to thank Liliana Quirós and
Mireya Isidro for their support in data compilation.
This work has been partially funded by the German Fed-
eral Ministry for the Environment, Nature Conservation and
Nuclear Safety (BMU; the CASCADE project which is part of
the International Climate Initiative).
References
Aguilar, E., Peterson, T.C., Ramirez Obando, P., Frutos, R., Retana, J.A.,
Solera, M., Soley, J., González Garcia, I., Araujo, R.M., Rosa-Santos, A.,

Herrera, L., Ruano, E., Sinay, J.J., Sánchez, E., Hernández Oviedo, G.I.,
Obed, F., Salgado, J.E., Vázquez, J.L., Baca, M., Guitiérrez, M., Centella,
C., Espinosa, J., Martínez, D., Olmedo, B., Ojeda Espinoza, C.E., Núñez,
R., Haylock, M., Benavides, H., and Mayorga, R. (2005). Changes
in precipitation and temperature extremes in Central America
and northern South America, 1961–2003. Journal of Geophysical
Research 110, 1–15. http://dx.doi.org/10.1029/2005JD006119.
AVRDC (2010). Prosperity for the Poor and Health for All: Strategic
Plan 2011–2025 (Shanhua, Taiwan: AVRDC), pp. 41.
AVRDC (2012a). Annual Report for 2011 (Shanhua, Taiwan: AVRDC),
pp. 65.
AVRDC (2012b). Year in Review, 2011 (Shanhua, Taiwan: AVRDC),
pp. 120–121.
AVRDC (2013a). Annual Report for 2012 (Shanhua, Taiwan: AVRDC),
pp. 65.
AVRDC (2013b). AVRDC’s eggplant rootstocks show promise to
combat bacterial wilt of tomato in Honduras. Feedback from the
Field 18, 1–2.
Biasutti, M., Sobel, A., Camargo, S., and Creyts, T. (2012). Projected
changes in the physical climate of the Gulf Coast and Caribbean.
Climatic Change 112, 819–845. http://dx.doi.org/10.1007/s10584-
011-0254-y.
Blanco, P.D., Colditz, R.R., López Saldaña, G., Hardtke, L.A., Llamas,
R.M., Mari, N.A., Fischer, A., Caride, C., Aceñolaza, P.G., del Valle, H.F.,
Lillo-Saavedra, M., Coronato, F., Opazo, S.A., Morelli, F., Anaya, J.A.,
Sione, W.F., Zamboni, P., and Arroyo, V.B. (2013). A land cover map
of Latin America and the Caribbean in the framework of the SERENA
project. Remote Sensing of Environment 132, 13–31. http://dx.doi.
org/10.1016/j.rse.2012.12.025.
ECLAC (2012). Statistical Yearbook for Latin America and the
Caribbean 2012 (Santiago de Chile, Chile: Economic Commission for
Latin America and the Caribbean, United Nations), pp. 220.

(2011). Genetic adjustment to changing climates: Vegetables. In Crop

Lotze-Campen and A.E. Hall, eds. (Chichester, UK: John Wiley). pp.
396–410. http://dx.doi.org/10.1002/9780470960929.ch27.
Engels, J.M.M., Ebert, A.W., Thormann, I., and de Vicente, M.C. (2006).
    
and implications for plant genetic resources conservation. Genetic
Resources and Crop Evolution 53, 1675–1688. http://dx.doi.
org/10.1007/s10722-005-1215-y.
Environment Canada (2012). Calculation of the 1971–2000 Climate
     
prods_servs/normals_documentation_e.html.
FAO (2013). FAOSTAT On-line. United Nations Food and Agriculture
organization, Rome, Italy. Available at: http://faostat3.fao.org/
home/index.html#COMPARE; accessed on 3 July 2013.
Firdaus, S., Van Heusden, A.W., Hidayati, N., Supena, E.D.J., Visser,
R.G.F., and Vosman, B. (2012). Resistance to Bemisia tabaci in tomato
wild relatives. Euphytica 187, 31–45. http://dx.doi.org/10.1007/
s10681-012-0704-2.
Folland, C.K., Karl, T.R., Christy, J.R., Clarke, R.A., Gruza, G.V., Jouzel,
J., Mann, M.E., Oerlemans, J., Salinger, M.J., and Wang, S.W. (2001).
Observed climate variability and change. In Climate Change 2001:
     
Assessment Report of the Intergovernmental Panel on Climate
Change, J.T. Houghton, Y. Ding, D.J. Griggs, M. Noguer, P.J. van der
Linden, X. Dai, K. Maskell and C.A. Johnson, eds. (Cambridge, UK:
Cambridge University Press), pp. 99–181.
Galhena, D.H., Freed, R., and Maredia, K.M. (2013). Home gardens:
A promising approach to enhance household food security and
wellbeing. Agriculture and Food Security 2, 1–26. http://dx.doi.
org/10.1186/2048-7010-2-8.
Garcia, B.E., Mejia, L., Melgar, S., Teni, R., Sanchez-Perez, A., Barillas,
A.C., Montes, L., Keuler, N.S., Salus, M.S., Havey, M.J., and Maxwell,
D.P. (2008). Effectiveness of the Ty-3 introgression for conferring
resistance in F3 families of tomato to bipartite begomoviruses in
Guatemala. Report of the Tomato Genetics Cooperative 58, 22–28.
Giorgi, F. (2006). Climate change hot-spots. Geophysical Research
Letters 33, 1–4. http://dx.doi.org/10.1029/2006GL025734.

vegetable breeding at AVRDC – The World Vegetable Center to meet
the challenges of climate change in the tropics. In Proceedings of
the Workshop on Crop Breeding and Management of Agricultural
Environment for Coping with Climate Change, D-H. Wu, M-T. Lu, T-H.
Tseng, Y-T. Wang and C-L. Hsiao, eds. (Taichung, Taiwan: Agricultural
Research Institute). pp. 163–172.
Hardoy, J., and Lankao, P.R. (2011). Latin American cities and climate
change: Challenges and options to mitigation and adaptation
responses. Current Opinion in Environmental Sustainability 3, 158–
163. http://dx.doi.org/10.1016/j.cosust.2011.01.004.
Hellin, J., Mark, L., and Meijer, M. (2009). Farmer organization,
collective action and market access in Meso-America. Food Policy 34,
16–22. http://dx.doi.org/10.1016/j.foodpol.2008.10.003.
Hidalgo, H.G., Amador, J.A., Alfaro, E.J., and Quesada, B. (2013).
Hydrological climate change projections for Central America.
76 European Journal of Horticultural Science
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
Journal of Hydrology 495, 94–112. http://dx.doi.org/10.1016/j.
jhydrol.2013.05.004.
Imbach, P., Molina, L., Locatelli, B., Roupsard, O., Ciais, P., Corrales,
L., and Mahé, G. (2010). Climatology-based regional modeling of
potential vegetation and average long-term runoff for Mesoamerica.
Hydrological Earth Systems Science 14, 1801–1817. http://dx.doi.
org/10.5194/hess-14-1801-2010.
Imbach, P., Molina, L., Locatelli, B., Roupsard, O., Mahé, G.,
Neilson, R., Corrales, L., Scholze, M., and Ciais, P. (2012). Modeling
potential equilibrium states of vegetation and terrestrial water
cycle of Mesoamerica under climate change scenarios. Journal
of Hydrometeorology 13, 665–680. http://dx.doi.org/10.1175/
JHM-D-11-023.1.
Intergovernmental Panel on Climate Change (IPCC). 2005. Guidance
notes for lead authors of the IPCC Fourth Assessment Report. IPCC
  
to Support Analysis of Risk and of Options (Maynooth, Ireland:
IPCC), pp. 1-4.
Jaramillo, J., Muchugu, E., Vega, F.E., Davis, A., Borgemeister, C.,
          
implications of climate change on coffee berry borer (Hypothenemus
hampei) and coffee production in east Africa. PLoS One Biology.
DOI: 10.1371/journal.pone.0024528. http://dx.doi.org/10.1371/
journal.pone.0024528.
     
Seamless SRTM Data (Cali, Colombia: International Center for
Tropical Agriculture [CIAT]). Http//SRTM.csi.cgiar.org.
Karmalkar, A.V., Bradely, R.S., and Diaz, H.F. (2008). Climate change
scenario for Costa Rican montane forests. Geophysical Research
Letters 35, 1–5. http://dx.doi.org/10.1029/2008GL033940.
Karmalkar, A.V., Bradely, R.S., and Diaz, H.F. (2011). Climate change in
Central America and Mexico: regional climate model validation and
climate change projections. Climate Dynamics 37, 606–629. http://
dx.doi.org/10.1007/s00382-011-1099-9.
Keatinge, J.D.H., Ledesma, D.R., Keatinge, F.J.D., and d’A. Hughes,
J. (2012a). Climate uncertainty: What response is needed from
vegetable agronomists worldwide? European Agronomy Society at

Keatinge, J.D.H., Chadha, M.L., d’A. Hughes, J., Easdown, W.J., Holmer,
R., Tenkouano, A., Yang, R.Y., Mavlyanova, R., Neave, S., Afari-Sefa,
V., Luther, G., Ravishankar, M., Ojiewo, C., Belarmino, M., Wang,
J.F., and Lin, M. (2012b). Vegetable gardens and their impact on
the attainment of the millennium development goals. Biological
Agriculture and Horticulture 28, 1–15. http://dx.doi.org/10.1080/
01448765.2012.681344.
Keatinge, J.D.H., Ledesma, D.R., d’A. Hughes, J., and Keatinge, F.J.D.
(2013). Urbanization: A potential factor in temperature estimates
for crop breeding programs at international agricultural research
institutes in the tropics. Journal of Semi-arid Tropical Agricultural
Research 11, 1–17.
Keatinge, J.D.H., Ledesma, D.R., Keatinge, F.J.D., and d’A. Hughes, J.
(2014). Projecting annual air temperature changes to 2025 and
beyond: Implications for vegetable horticulture worldwide. Journal
of Agricultural Science, Cambridge 152, 38–57. http://dx.doi.
org/10.1017/S0021859612000913.
Keatinge, J.D.H., Ledesma, D.R., d’A. Hughes, J., and Keatinge, F.J.D.
(2015). Assessing the value of long term historical air temperature
records in the estimation of warming trends for use by agricultural
scientists globally. Acta Advances in Agricultural Sciences 3, 1–19.
Kugblenu, Y.O., Oppong Danso, E., Ofori, K., Andersen, M.N., Abenney-
Mickson, S., Sabi, E.B., Plauborg, F., Abekoe, M.K., Ofusu-Anim, J.,
Ortiz, R., and Jorgensen, T. (2013). Screening tomato genotypes for
adaptation to high temperature in West Africa. Acta Agriculturae
Scandinavica, Section B – Soil & Plant Science 63, 516–522. http://
dx.doi.org/10.1080/09064710.2013.813062.
Lin, C.H., Hsu, S.T., Tzeng, K.C., and Wang, J.F. (2008). Application of a
preliminary screen to select locally adapted resistant rootstock and
soil amendment for integrated management of tomato bacterial wilt
in Taiwan. Plant Disease 92, 909–916. http://dx.doi.org/10.1094/
PDIS-92-6-0909.
Madakadze, R.M., and Waramba, J.K. (2004). Effect of preharvest
factors on the quality of vegetables produced in the tropics –
Vegetables: Growing environment and quality of produce. In
Development Growth Quality of Vegetables Vol. 1, Preharvest
Practices, S.M. Ramdane Dris, and S.M. Jain, eds. (Dordrecht,
Netherlands: Kluwer Academic), pp. 1–36.
Malhi, Y., and Wright, J. (2004). Spatial patterns and recent trends in
the climate of tropical rainforest regions. Philosophical Transactions
of the Royal Society of London. Series B: Biological Sciences 359,
311–329. http://dx.doi.org/10.1098/rstb.2003.1433.
Nakaegawa, T., Kitoh, A., Murakami, H., and Kusunoki, S. (2013).
Annual maximum 5-day rainfall total and maximum number of
consecutive dry days over Central America and the Caribbean in
       
circulation model with three different horizontal resolutions.
Theoretical and Applied Climatology 116, 155–168. http://dx.doi.
org/10.1007/s00704-013-0934-9.
Neelin, J.D., Münnich, M., Su, H., Meyerson, J.E., and Holloway, C.E.
(2006). Tropical drying trends in global warming models and
observations. Proceedings of the National Academy of Sciences
of the United States of America 103, 6110–6115. http://dx.doi.
org/10.1073/pnas.0601798103.

M., Hoogendoorn, C., Keatinge, J.D.H., Molden, D., and Roy, A.
(2014). Transforming rural livelihoods and landscapes: Sustainable
improvements to incomes, food security and the environment.
AIRCA White Paper (Nairobi, Kenya: AIRCA). Available at http://
cropsforthefuture.org/airca2/?page_id=14.

Quezada, M.E.M. (2011). Sustainable production and marketing of
vegetables in Central America. HORT-CRSP Project Report (Davis,
USA: University of California), pp. 146. http://hortcrsp.ucdavis.edu/
evaldocs/iipbinder/reports/nienhuis.pdf.
         
and Quezada, M.E.M. (2012). Seeds of Hope. HORT-CRSP Project
Report (Davis, USA: University of California), pp. 49. http://hortcrsp.
ucdavis.edu/evaldocs/pilotprojects/reports/nienhuis.pdf.
Parry, M.L., Canziani, O.F., Palutikof, J.P., Van der Linden, P.J., and
Hanson, C.E. (eds.). (2007). Contribution of Working Group II to
the Fourth Assessment Report of the Intergovernmental Panel on
Climate Change (Cambridge, UK: Cambridge University Press), pp.
976.
Quintana-Gomez, R.A. (1999). Trends of maximum and minimum
temperatures in northern South America. Journal of Climate 12, 2104–
2112. http://dx.doi.org/10.1175/1520-0442(1999)012<2104:
TOMAMT>2.0.CO;2.
Ramirez-Villegas, J., Challinor, A.J., Thornton, P.K., and Jarvis, A. (2013).
Implications of regional improvement in global climate models for
agricultural impact research. Environmental Research Letters 8,
1–12. http://dx.doi.org/10.1088/1748-9326/8/2/024018.
Sheu, Z.M., Chen, J.R., and Wang, T.C. (2009). First report of
the A2 mating type of Phytophthora capsici infecting peppers
(Capsicum annuum) in Taiwan. Plant Disease 93, 548. http://dx.doi.
org/10.1094/PDIS-93-5-0548C.
Tsai, W.S., Shih, S.L., Kenyon, L., Green, S.K., and Jan, F.J. (2011).
Temporal distribution and pathogenicity of the predominant
Volume 81 | Issue 2 | April 2016 77
Keatinge et al. | Air temperature trends in Mesoamerica and the future of horticulture
tomato-infecting begomoviruses in Taiwan. Plant Pathology 60, 787–
799. http://dx.doi.org/10.1111/j.1365-3059.2011.02424.x.
Vavilov, N.I. (1926). Studies on the Origin of Cultivated Plants
(Leningrad, Russia: Institute of Applied Botany and Plant Breeding).
Vincent, L.A., Peterson, T.C., Barros ,V.R., Marino, M.B., Rusticucci,
M., Carrasco, G., Ramirez, E., Alves, L.M., Ambrizzi, T., Berlato, M.A.,
Grimm, A.M., Marengo, J.A., Molion, L., Moncunill, D.F., Rebello,
E., Anunciacao, Y.M.T., Quintana, J., Santos, J.L., Baez, J., Coronel,
G., Garcia, J., Trebejo, I., Bidegain, M., Haylock, M.R., and Karoly, D.
(2005). Observed trends in indices of daily temperature extremes
in South America 1960–2000. American Meteorological Society 18,
5011–5023. http://dx.doi.org/10.1175/jcli3589.1.
Wolfe, D.W. (2013). Contributions to climate change solutions from
the agronomy perspective. In Handbook of Climate Change and
Agroecosystems: Global and Regional Aspects and Implications, D.
Hillel and C. Rosenzweig, eds. (London, UK: Imperial College Press),
pp. 11–29.
World Meteorological Organisation (2013). The Global Climate
2001–2010: A Decade of Climate Extremes Summary Report. WMO
Report 1119 (Geneva, Switzerland: WMO), pp. 16.
Zeven, A.C., and De Wet, J.M.J. (1982). Dictionary of Cultivated Plants
and their Regions of Diversity: Excluding Ornamentals, Forest Trees
and Lower Plants (Wageningen, The Netherlands: CAPD).
Zhang, X., and Cai, X. (2013). Climate change impacts on global
    40, 1111–
1117. http://dx.doi.org/10.1002/grl.50279.
Received: Mar. 11, 2016
Accepted: Mar. 15, 2016
Addresses of authors:
J.D.H. Keatinge1,*, P. Imbach2, D.R. Ledesma1, J. d’A. Hughes1,
F.J.D. Keatinge3, J. Nienhuis4, P. Hanson1, A.W. Ebert1 and
S. Kumar1
1 AVRDC – The World Vegetable Center, Shanhua, Tainan,
Taiwan
2 CATIE (Tropical Agricultural Research and Higher
Education Center), Climate Change Program, Turrialba,
Cartago, Costa Rica
3 Department of Geography, University of Florida,
Gainesville, FL 32611, USA
4 College of Agricultural and Life Sciences, University of
Wisconsin, Madison, WI 53706, USA
* Corresponding author; E-mail: dyno@keatinge.co.uk
... Likewise, in terms of air temperature for this region, monthly minimum temperatures were seen to increase substantially at Nakuru, Kenya, yet no change was discernible in monthly maximum temperatures ( Ogutu et al., 2012). Similarly, somewhat contradictory results in temperature trends are evident elsewhere, such as in Asia ( Keatinge et al., 2014) and Mesoamerica ( Keatinge et al., 2016). ...
... This will also be true for major viral vectors such as whiteflies, aphids and thrips (Hanson et al., 2011). The impact will occur not only on global vegetables such as tomato, eggplant, cabbages and green beans but also on a wide range of African indigenous/traditional vegetables ( Keatinge et al., 2016). Furthermore, the impact will include damage to African staple crops of which part can be used as secondary vegetables, such as cowpea leaves and green pods (Yang and Keding, 2009), cassava leaves (Ufuan Achidi et al., 2005), pigeon pea as green peas and even green maize for roasting (McCann, 2001). ...
Article
The study was conducted to determine whether likely global climatic uncertainty in the future will pose substantive risk to small-scale vegetable producers in Africa, and to consider whether climate change threatens the development and sustainability of improved vegetable horticultural systems in Africa. Annual average air temperature and rainfall totals were assessed over the period 1975-2014 or, where possible, for rainfall for longer periods approaching 100 years; the trends in these data sets were determined through linear regression techniques. Predictions of the likely values of annual average air temperatures in the next 25, 50, 75 and 100 years were made. Considerable variability in trends is reported ranging from extremely fast warming in Tunis, Tunisia contrasting with slight cooling in Bamako, Mali. Annual variability in rainfall was substantive but there were no long-term trends of consequence, even when considered over the last 100 years. Consequently, the sustainability of vegetable production will be threatened mostly by changes in pest (e.g., weeds, insects, fungi, bacteria and viruses) damage to crops in small-scale production systems. A call is made for national governments to give these issues enhanced priority in the distribution of future research and capacity-building resources, as most of these production stressors are under-researched and evident solutions to such problems are not currently available. © 2018 International Society for Horticultural Science. All rights reserved.
Article
Full-text available
Plant breeders globally are presently handicapped by uncertain estimates of future increases in annual air temperatures. In particular, lack of location-specific estimates in the next 25 years is likely to hinder their attempts to incorporate specifically additional heat tolerance and pest resistance into new varieties in addition to the many other breeding and agronomic issues associated with global climate uncertainty which challenge agricultural scientists. Failure to adequately predict the likely future suite of challenging abiotic and biotic stresses to crops may render the new varieties needed for the coming generations to be less productive and with less effective longevity, bringing severe global consequences. In this paper we have made an attempt to provide estimates of the likely range of increases in annual average air temperature 25 years into the future across a wide range of locations. These were selected, essentially at random, but with provisos that the sites should be in areas suitable for cropping, and have had an uninterrupted, freely available data stream for at least 100 years. The sites showed great variability in likely temperature increases in 2039, from around a maximum increase equivalent to 4.5 o C per hundred years to a minimum of no change (1975-2013). There was also considerable variability when the time period over which the analysis was performed was changed from 1975-2013 to more historic or more recent periods. Approximately half of the sites analyzed for 1975-2013 project no significant future increase in air temperature. With longer data runs most sites showed at least modest increases in temperature, with the extreme case—Tbilisi in Georgia— requiring a return to 1881 before a significant increase was recorded. If a default period has to be selected then 1975-2013 remains the pragmatic option.
Article
Full-text available
Indigenous (traditional) vegetables are best defined as species that are locally important for the sustainability of economies, human nutrition and health, and social systems - but which have yet to attain global recognition to the same extent as major vegetable commodities such as tomato or cabbage. Given the hundreds of indigenous vegetables consumed worldwide, their accumulated value for mankind is considerable. These species deserve much greater recognition and investment in agricultural research and development than they have presently. Indigenous vegetables are primary candidates for greater use of crop biodiversity in horticulture as they are already consumed and enjoyed locally and can be produced profitably in both rural and urban environments. Yet many such species have received little scientific attention to date. More effort in research and development would likely produce rewarding results, as productivity increases in these neglected crops are much easier to realize than for intensively researched staple cereals. Questions therefore are: 1) How can we rescue, conserve and utilize the genetic diversity of cultivated and wild forms of indigenous vegetables under threat of genetic erosion?; 2) How can the lack of quality seed be overcome?; 3) Given the increased levels of biotic and abiotic stresses driven by climate change, as well as existing rural-urban migration trends, how can these indigenous vegetables help produce sufficient quantities of quality food?; 4) Can postharvest management be improved to make market chains more effective and profitable?; 5) Can greater consumption of such diverse and nutritious indigenous vegetables be encouraged, knowing that changing dietary habits is a difficult exercise?.
Article
Full-text available
Data sets were accumulated of annual average maximum, minimum and mean air temperature from a range of sites worldwide, specifically from non-urban locations such as agricultural research institutes, universities and other rural or island locations for the period 1975–2011 or longer where data were available. The data sets were then analysed using linear regression to determine the rate and direction of change in temperature over the reference periods. This analysis was performed to provide vegetable scientists with likely future temperature change scenarios up to 2025 and 2050 (on the assumption that recent trends are maintained) so that breeding, agronomic and other related research programmes may better respond to potential challenges from abiotic and biotic stresses to vegetable production. Substantial variation was evident between sites and between time runs at specific sites. At some locations rapid increases in air temperature are projected, such as for sites in East Asia, but at other locations little change is evident; in rare cases, local cooling is shown. The implications of variability and change in air temperature in the context of constraints to vegetable production and the opportunities to exploit the range of genetic diversity available in climatically uncertain environments are discussed. It is believed that modern agricultural science can address successfully the problems raised by climate uncertainty, yet the lack of sufficient, immediate investment in horticultural disciplines worldwide places the world at severe risk of failing to attain effective food and nutritional security.
Article
Full-text available
Plant breeders globally are presently handicapped by uncertain estimates of future increases in annual air temperatures. In particular, lack of location-specific estimates in the next 25 years is likely to hinder their attempts to incorporate specifically additional heat tolerance and pest resistance into new varieties in addition to the many other breeding and agronomic issues associated with global climate uncertainty which challenge agricultural scientists. Failure to adequately predict the likely future suite of challenging abiotic and biotic stresses to crops may render the new varieties needed for the coming generations to be less productive and with less effective longevity, bringing severe global consequences. In this paper we have made an attempt to provide estimates of the likely range of increases in annual average air temperature 25 years into the future across a wide range of locations. These were selected, essentially at random, but with provisos that the sites should be in areas suitable for cropping, and have had an uninterrupted, freely available data stream for at least 100 years. The sites showed great variability in likely temperature increases in 2039, from around a maximum increase equivalent to 4.5 o C per hundred years to a minimum of no change (1975-2013). There was also considerable variability when the time period over which the analysis was performed was changed from 1975-2013 to more historic or more recent periods. Approximately half of the sites analyzed for 1975-2013 project no significant future increase in air temperature. With longer data runs most sites showed at least modest increases in temperature, with the extreme case—Tbilisi in Georgia— requiring a return to 1881 before a significant increase was recorded. If a default period has to be selected then 1975-2013 remains the pragmatic option.
Article
Full-text available
Data sets were accumulated of annual average maximum, minimum and mean air temperature from a range of sites worldwide, specifically from non-urban locations such as agricultural research institutes, universities and other rural or island locations for the period 1975–2011 or longer where data were available. The data sets were then analysed using linear regression to determine the rate and direction of change in temperature over the reference periods. This analysis was performed to provide vegetable scientists with likely future temperature change scenarios up to 2025 and 2050 (on the assumption that recent trends are maintained) so that breeding, agronomic and other related research programmes may better respond to potential challenges from abiotic and biotic stresses to vegetable production. Substantial variation was evident between sites and between time runs at specific sites. At some locations rapid increases in air temperature are projected, such as for sites in East Asia, but at other locations little change is evident; in rare cases, local cooling is shown. The implications of variability and change in air temperature in the context of constraints to vegetable production and the opportunities to exploit the range of genetic diversity available in climatically uncertain environments are discussed. It is believed that modern agricultural science can address successfully the problems raised by climate uncertainty, yet the lack of sufficient, immediate investment in horticultural disciplines worldwide places the world at severe risk of failing to attain effective food and nutritional security.
Article
Full-text available
hydrol-earth-syst-sci.net/14/1/2010/ doi:10.5194/hess-14-1-2010 © Author(s) 2010. CC Attribution 3.0 License. Abstract. Mean annual cycles of runoff, evapotranspira-tion, leaf area index (LAI) and potential vegetation were modelled for Mesoamerica using the SVAT model MAPSS with different climatology datasets. We calibrated and val-idated the model after building a comprehensive database of regional runoff, climate, soils and LAI. The performance of several gridded precipitation climatology datasets (CRU, FCLIM, WorldClim, TRMM, WindPPT and TCMF) was evaluated and FCLIM produced the most realistic runoff. Annual runoff was successfully predicted (R 2 =0.84) for a set of 138 catchments, with a low runoff bias (12%) that might originate from an underestimation of the precipitation over cloud forests. The residuals were larger in small catchments but remained homogeneous across elevation, precipitation, and land-use gradients. Assuming a uniform distribution of parameters around literature values, and using a Monte Carlo-type approach, we estimated an average model uncer-tainty of 42% of the annual runoff. The MAPSS model was most sensitive to the parameterization of stomatal conduc-tance. Monthly runoff seasonality was mimicked "fairly" in 78% of the catchments. Predicted LAI was consistent with MODIS collection 5 and GLOBCARBON remotely sensed global products. The simulated evapotranspiration:runoff ra-tio increased exponentially for low precipitation areas, high-lighting the importance of accurately modelling evapotran-spiration below 1500 mm of annual rainfall with the help of SVAT models such as MAPSS. We propose the first high-Correspondence to: P. Imbach (pimbach@catie.ac.cr) resolution (1 km 2 pixel) maps combining average long-term runoff, evapotranspiration, leaf area index and potential veg-etation types for Mesoamerica.
Book
Climate change is no longer merely projected to occur in the indeterminate future. It has already begun to be manifested in the weather regimes affecting agroecosystems, food production, and rural livelihoods in many regions around the world. It is a real and growing challenge to the world at large and in particular to the scientific community, which is called upon with increasing urgency to respond effectively. The second volume in the ICP Series on Climate Change Impacts, Adaptation, and Mitigation, Handbook of Climate Change and Agroecosystems: Global and Regional Aspects and Implications is published jointly by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America and Imperial College Press. The ongoing series is dedicated to elucidating the actual and potential impacts of climate change, and to formulating effective responses to this global challenge. It is designed to inform, spur, and integrate the work of leading researchers in the major regions of the world, and to further international cooperation in this crucial field.