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Climate Impacts in Mesoamerican Countries:
Results from Global and Regional Climate Models
Robert Oglesby, Clinton Rowe, and Cynthia Hays
University of Nebraska-Lincoln
About the Authors
Robert Oglesby is Professor of Climate Modeling in the Department of Geosciences and
the School of Natural Resources of the University of Nebraska-Lincoln. He held prior
positions as a Senior Research Scientist for NASA, and as Associate Professor of
Atmospheric Sciences at Purdue University. He has over twenty years experience in
using global and regional models to address questions of past, present, and future climate.
Clinton Rowe is a Professor in the Meteorology/Climatology Program in the Department
of Geosciences at the University of Nebraska-Lincoln. He has over twenty years
experience in modeling land-surface interactions with the atmosphere to investigate their
impacts on the climate system at various scales.
Cynthia Hays is a Technologist at the University of Nebraska, Lincoln, with over twentyfive years of experience in running global and regional climate models and using their
output for impacts assessment.
Cover Image: Preliminary results from a Regional Climate Model (RCM) climate change
scenario for Mesoamerica.
EXECUTIVE SUMMARY
The Mesoamerican region (the group of countries from Mexico to Colombia) is already
suffering the effects of climate change and its limited capacity to adapt, a product of its
socio-economic context, makes it highly vulnerable. The goal of this document is to
provide an interim report detailing the latest state-of-the-art knowledge of climate change
impacts for Mesoamerica between now and AD 2050. Results from a recent set of global
climate model runs are discussed first. Focus then shifts to a set of regional climate model
runs currently underway. We present some preliminary result here and expect to update
this evolving document regularly as new results are obtained up until the termination date
of 30 September 2010. We also present some results from a previous regional climate
change study for Central America.
Based on analyses from global climate models, the Intergovernmental Panel on Climate
Change Fourth Assessment Report (Working Group I, Ch. 11) summarizes for
Mesoamerica:
All of Central and South America is very likely to warm during this century. The
annual mean warming is likely to be larger than the global mean warming.
Annual precipitation is likely to decrease in most of Central America, with the
relatively dry boreal spring becoming drier. A caveat at the local scale is that
changes in atmospheric circulation may induce large local variability in
precipitation changes in mountainous areas.
Analyses from the regional climate models support the global model results concerning
temperature, and provide much more detail on how local topography and land use affect
temperatures, and how they may change. Precipitation is another matter, as the regional
models suggest that the global model results may be unreliable, due to the inability to
adequately resolve topographic effects. In particular, the Intergovernmental Panel on
Climate Change conclusion that precipitation will decrease for much of Central America
is questioned. It is possible that much of the region will see little change, or even an
increase.
In a previous study (funded by the U.S. Agency for International Development), we used
a regional climate model to investigate climate change in southern Mexico and Central
America during the 21st century. Importantly, the simulated climate changes for
Mesoamerica due to global warming were far smaller than those from those due to
deforestation.
As the evolving nature of this document itself demonstrates, generating regional climate
change impacts scenarios for Mesoamerica is an ongoing process. Plans should be laid
now to utilize the next generation Intergovernmental Panel on Climate Change Fifth
Assessment Report information. Potential regional causes of climate change such as due
to land use changes also need to be investigated more thoroughly.
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INTRODUCTION
The Mesoamerican region (the group of countries from Mexico to Colombia) is already
suffering the effects of climate change and its limited capacity to adapt, a product of its
socio-economic context, makes it highly vulnerable. Therefore, it is of utmost importance
to help support these countries in their battle to address the effects of climate change and
achieve long-term development goals. One way of contributing to this effort is by
providing the region with climate change scenarios tailored to Mesoamerica. The goal of
this document is to provide an interim report detailing the latest state-of-the-art
knowledge of climate change impacts for Mesoamerica between now and AD 2050.
Results from a recent set of global climate model runs are discussed first, including the
limitations involved. Focus then shifts to a set of regional climate model runs currently
underway. These latter runs were developed at a workshop held in July 2009; a specific
set of regional climate change scenarios was developed during the workshop. The model
simulations are ongoing; we present some preliminary result here and expect to update
this evolving document regularly as new results are obtained up until the termination date
of 30 September 2010. We also present some results from a previous regional climate
change study for Central America that compared the effects of global warming to those
due to local deforestation.
IPCC GLOBAL CLIMATE MODEL SCENARIOS
Over the past 20 years, the Intergovernmental Panel on Climate Change1 (IPCC) has
provided a series of projections of possible future climate change, primarily through use
of global climate models (GCMs). The most recent Fourth Assessment Report (AR4)
projection, released in 2007 (IPCC 2007), represents a major advance of this assessment
of climate change projections compared with previous reports because of the larger
number of simulations available from a broader range of models. Taken together with
additional information from observations, these provide a quantitative basis for
estimating likelihoods for many aspects of future climate change. Model simulations
cover a range of possible futures including idealized emission or concentration
assumptions. We provide a summary below of key results and findings, especially for
Mesoamerica. We also point out the limitations in using results just from global models.
Figure 1 shows global mean near-surface temperatures over the 20th century from
observations (black) and as obtained from 58 simulations produced by 14 different
climate models driven by both natural and human-caused factors that influence climate
(yellow). The mean of all these runs is also shown (thick red line). Temperature
anomalies are shown relative to the 1901 to 1950 mean. Vertical grey lines indicate the
1
The IPCC is a scientific body organized by the United Nations Environmental Programme (UNEP) and
the World Meteorological Organization (WMO) to study and assess climate change and is open to
representatives from all their member countries (for additional information on the IPCC’s role and mission,
see http://www.ipcc.ch/organization/organization.htm).
1
Figure 1: Comparison between global mean surface temperature anomalies (°C) from observations
(black) and AOGCM simulations forced with (a) both anthropogenic and natural forcings and (b)
natural forcings only. All data are shown as global mean temperature anomalies relative to the
period 1901 to 1950, as observed (black, Hadley Centre/Climatic Research Unit gridded surface
temperature data set and, in (a) as obtained from 58 simulations produced by 14 models with both
anthropogenic and natural forcings. The multimodel ensemble mean is shown as a thick red curve
and individual simulations are shown as thin yellow curves. Vertical grey lines indicate the timing of
major volcanic events. Those simulations that ended before 2005 were extended to 2005 by using the
first few years of the IPCC Special Report on Emission Scenarios (SRES) A1B scenario simulations
that continued from the respective 20th-century simulations, where available. The simulated global
mean temperature anomalies in (b) are from 19 simulations produced by five models with natural
forcings only. The multi-model ensemble mean is shown as a thick blue curve and individual
simulations are shown as thin blue curves. Simulations are selected that do not exhibit excessive drift
in their control simulations (no more than 0.2°C per century). Each simulation was sampled so that
coverage corresponds to that of the observations (from IPCC, AR4, WG-I, Figure 9.5).
timing of major volcanic eruptions. The models all do a reasonable job of simulating the
observed temperatures, especially the upward trend during the latter portion. Importantly,
the global climate models cannot reproduce the recent, observed warming without
including anthropogenic forcings – particularly greenhouse gas (GHG) emissions. The
models all agree on direction of change, although they differ in the magnitude of
projected change.
Figure 2 shows changes in precipitation (in percent) for the period 2090–2099, relative to
1980–1999. Values are multi-model averages based on the SRES A1B emission scenario2
for December to February (DJF) and June to August (JJA). White areas are where fewer
than 66% of the models agree in the sign of the change and stippled areas are where more
than 90% of the models agree in the sign of the change. This is a global plot, making it
difficult to distinguish results for any one region, although overall tendencies are clear –
the subtropics tend to have reductions in precipitation, while the equatorial regions and
the mid-latitudes have increases in precipitation. In other words, those regions dry at
present tend to get drier, while wet regions tend to become even wetter.
2
The Special Report on Emissions Scenarios (SRES) is a report prepared by the Intergovernmental Panel
on Climate Change (IPCC) for the Third Assessment Report (TAR) in 2001. Scenario families contain
individual scenarios with common themes. The six families of scenarios discussed in the IPCC's Third
Assessment Report (TAR) and Fourth Assessment Report (AR4) are A1FI, A1B, A1T, A2, B1, and B2.
2
Figure 2: Relative changes in precipitation (in percent) for the period 2090–2099, relative to 1980–
1999. Values are multi-model averages based on the SRES A1B scenario for December to February
(left) and June to August (right). White areas are where less than 66% of the models agree in the sign
of the change and stippled areas are where more than 90% of the models agree in the sign of the
change (from IPCC AR4 WG-I, SPM, Figure 7).
These global results provide confidence in the models, but do not by themselves yield
useful results at the regional scale. Figure 3 shows temperature and precipitation changes
over Central and South America from the MMD-A1B3 simulations using 21 global
climate models. Based on analyses from these same global models, the IPCC Fourth
Assessment Report (AR4) (WG-I, Ch. 11) summarizes for Mesoamerica:
All of Central and South America is very likely to warm during this century. The
annual mean warming is likely to be larger than the global mean warming.
Annual precipitation is likely to decrease in most of Central America, with the
relatively dry boreal spring becoming drier. A caveat at the local scale is that
changes in atmospheric circulation may induce large local variability in
precipitation changes in mountainous areas.
Furthermore, they note that:
Systematic errors in simulating current mean tropical climate and its variability
(Section 8.6) and the large intermodal differences in future changes in El Niño
amplitude preclude a conclusive assessment of the regional changes over large
areas of Central and South America. Most MMD models are poor at reproducing
the regional precipitation patterns in their control experiments and have a small
signal to- noise ratio. As with all landmasses, the feedbacks from land use and
land cover change are not well accommodated, and lend some degree of
uncertainty. Over Central America, tropical cyclones may become an additional
source of uncertainty for regional scenarios of climate change, since the summer
precipitation over this region may be affected by systematic changes in hurricane
tracks and intensity.
Summarizing the results of one of the business-as-usual scenarios,
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A key feature of IPCC is the collection of a comprehensive set of model output, referred to here as the
Multi-Model Data set (MMD). This has allowed hundreds of researchers to scrutinize the models from a
variety of perspectives.
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Figure 3: Temperature and precipitation changes over Central and South America from the MMDA1B simulations. Top row: Annual mean, DJF and JJA temperature change between 1980 to 1999
and 2080 to 2099, averaged over 21 models. Middle row: same as top, but for fractional change in
precipitation. Bottom row: number of models out of 21 that project increases in precipitation (from
IPCC, AR4, WG-I, Figure 11.15).
The warming as simulated by the MMD-A1B projections increases approximately
linearly with time during this century. The annual mean warming under the A1B
scenario between 1980 to 1999 and 2080 to 2099 varies in the CAM [Central
American] region from 1.8°C to 5.0°C, with half of the models within 2.6°C to
3.6°C and a median of 3.2°C.
The MMD models suggest a general decrease in precipitation over most of
Central America, where the median annual change by the end of the 21st century
is –9% under the A1B scenario, and half of the models project area mean changes
from –16 to –5%, although the full range of the projections extends from –48 to
+9%. Area mean precipitation in Central America decreases in most models in
all seasons. It is only in some parts of northeastern Mexico and over the eastern
Pacific, where the ITCZ [inter-tropical convergence zone] forms during JJA, that
increases in summer precipitation are projected. However, since tropical storms
can contribute a significant fraction of the rainfall in the hurricane season in this
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region, these conclusions might be modified by the possibility of increased
rainfall in storms not well captured by these global models. In particular, if the
number of storms does not change, Knutson and Tuleya (2004) estimate nearly a
20% increase in average precipitation rate within 100 km of the storm centre at
the time of atmospheric carbon dioxide (CO2) doubling.’
The above analysis represents the current state-of-the-art as based on global climate
models. While useful in projecting large-scale changes and effects, the coarse horizontal
resolution (approximately 150 km) of the models also limits their usefulness when
projecting changes at the regional or local scale. One trivial indication of this is the
difficulty in obtaining clear maps of results for Mesoamerica – one must resort to either
the ‘top’ of maps for South America, or the ‘bottom’ of maps for North America! Even
more important is the inability of the global models to resolve regions of complex
topography. As one obvious indication of this, recall that the IPCC MMD (global)
models suggest a general decrease in precipitation over Central America during the
remainder of this century. In a study (described in more detail below), Oglesby et al.
(2005; 2009) used the MM5 regional climate model at a horizontal resolution of 12 km to
investigate Central American climate change during the 21st century. They found a
reduction in precipitation only along the Atlantic coast, with little change, or even a small
increase, over the interior and Pacific coast regions. They attributed this difference to the
inability of the global model to resolve the mountainous topography of Central America.
Because of this, the global models had the trade winds blowing (spuriously) unimpeded
across the entire isthmus, when in reality they are blocked by the mountains. At 150 km
resolution, the mountainous terrain of Central America is simply not resolved at all. Since
the mountains of Central America provide probably the second-largest regional climatic
control (after latitude), especially for precipitation, use of GCM results ‘as-is’ is simply
pointless; worse, as described later, it can lead to conclusions diametrically opposed to
those produced when the mountains are resolved. If the global model cannot accurately
simulate present-day precipitation patterns, it is also difficult to trust their projections of
future climate change. This brings us to the key topic of regional climate models.
REGIONAL CLIMATE CHANGE SCENARIOS
Recognizing both the limitations on the use of global model results and the lack of
available regional climate model scenarios4, a workshop was convened in July 2009 at
the National Center for Atmospheric Research (NCAR) in Boulder, CO. The goal of this
workshop was to develop advanced climate change scenarios and impacts assessment
capability in the Latin America and Caribbean region. As part of this general training, a
specific set of regional climate change scenarios was developed and is being
implemented. The NCAR Weather Research and Forecasting (WRF) regional model is
being used to make these scenarios.
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The IPCC (2007) noted that: ‘Regional models are still being tested and developed for this region.’
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Based on group discussions and consideration of individual national needs, a domain at
12 km spatial resolution was chosen to include all of Mesoamerica (plus Peru and
Jamaica). Each simulation also includes a large outer region, or ‘domain’ at 48 km that
extends out over the adjacent oceans. The purpose of this outer region is to transition
from the global model (at approximately 150 km resolution) to the 12 km domain of
primary interest. Also, portions of central Mexico and Colombia are covered by separate
4 km domains embedded within the 12 km domain. (These latter, very high resolution
domains in regions of complex topography are experimental in nature and intended to see
if they better resolve the strong topographic controls on precipitation in these regions.)
The domains are all shown in Figure 4. Large-scale forcing is provided by an IPCC A2
(‘business as usual’) global climate model scenario for 2050-2052, along with a ‘presentday’ control for 2000-2002. The global climate scenario was provided by NCAR using
their Community Climate System Model (CCSM).
Figure 4: Regional climate model domains for Mesoamerica, showing the 48 km domain (left), the 12
km domain (top right) and the two 4 km domains for Mexico and Colombia (bottom right).
A three-year control forced by NCEP (U.S. National Centers for Environmental
Prediction) reanalyses is also being made for the years 1991-1993. The purpose of this
run is to verify that the model is adequate at simulating the present-day climate of
Mesoamerica. Of particular interest are issues concerning resolution, topography, and
availability of observations5. Some preliminary results are presented below. Figure 5
shows time series from the regional model at the various resolutions, as compared to
station observations, for Mexico City, Mexico and Cali Colombia. As a general
assessment: (1) the complex topography means that elevational effects are extremely
important, and (2) it is essential to identify a nearest neighbor gridpoint that also has a
similar elevation to the station to be compared with. This is not always easy; the Cali
example shows that 4 km and 12 km resolutions can resolve the deep Cacua Valley much
better than 48 km, and indeed agree quite well with observations. For Mexico City, on
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In addition to validating the model; observations are critical to assessment of vulnerabilities and impacts
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the other hand, it is more difficult to identify an appropriate model gridpoint. Averaging
several nearby gridpoints is worse than useless as it would yield some average elevation
not actually experienced by any station. Overall, the 12 km and 4 km domains appear to
adequately simulate the weather and hence climate at these two stations.
Figure 5: Time series of temperature (°C) for the first 80 days of 1991 as simulated by WRF at 48, 12,
and 4 km resolution and compared to station observations for Mexico City, Mexico and Cali,
Colombia. The legend indicates the actual elevation of each station, as well as the elevation and
distance from the station of the nearest WRF grid point.
PRELIMINARY RESULTS - CLIMATE CHANGE SCENARIOS
As of this writing (early January 2010) most of 2000 and 2050 have been completed for
the climate change runs, while most of 1993 has been completed for the control run.
Completion is expected in late February or March 2010. We show some preliminary plots
here; these will be periodically updated in an online version of this document, via the
following website: http://weather.unl.edu/RCM/reports/impacts/. It is essential to keep in
mind that results from just one year from each of the ‘climate change’ and ‘present-day’
simulations is currently shown. Any climate change must compete with short timescale
'natural' climate variability, which can be quite large year-to-year. Nonetheless, general
trends are already clear, and as the runs progress (and the website is updated) the effects
of this interannual variability will begin to cancel out, leaving the longer-term climate
change signal more obvious.
Figure 6 shows temperatures for the 12 km 'Mesoamerica' domain for February 2050, and
the difference between February 2050 and February 2000. The plot for 2050 shows a
realistic distribution of temperatures, with latitudinal and altitudinal controls clearly
evident. Compared to 2000, a general warming is seen, largest (about 5°C) in northern
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Figure 6: (left) monthly mean temperature (°C) for February 2050 and (right) the difference between
the February monthly mean temperatures for 2050 minus 2000, for the WRF 12 km domain. The
boxes indicate the locations of the 4 km domains for Mexico and Colombia.
Mexico (and the southern U.S.). The mountainous areas of central Mexico, Guatemala,
Costa Rica, and Colombia show little change, or even a slight cooling. The cooling is
almost certainly a function of interannual variability, but the clear implication is that
temperature changes in these regions are likely smaller than elsewhere. The rest of
Mesoamerica shows a general warming of 1-2°C.
Figure 7 shows temperatures for the very high-resolution, 4 km ‘Mexico’ domain for
February 2050, and the difference between February 2050 and February 2000. Figure 8
shows temperatures for the very high-resolution, 4 km ‘Colombia’ domain for February
2050, and the difference between February 2050 and February 2000. In each case, the
basic results are like those of the 12 km case, but it is clear that the topography is much
better resolved. The lack of warming in the high elevations is clearly highlighted.
Figure 9 shows precipitation (rainfall plus any snowfall) for the 12 km domain for
February 2050, and the difference between February 2050 and February 2000. Obvious
on the plot for 2050 are the effects of mountains, as well as the low-relief Isthmus of
Tehuantepec. Compared to 2000, northern Mexico shows increased precipitation, as do
the mountainous regions of Colombia. Though outside the region of immediate interest,
Ecuador and northern Peru show very large decreases. Southern Mexico and Central
America show a mixed response; some regions have increased precipitation, while in
others it decreases. This is in contradiction with global studies, which suggest a general
decrease, but cannot adequately resolve the steep, complex topography. Clearly, these
topographic controls on precipitation are at least as important as for temperature. Figures
10 and 11 show the above effects even more clearly for central Mexico and Colombia.
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Figure 7: (left) monthly mean temperature (°C) for February 2050 and (right) the difference between
the February monthly mean temperatures for 2050 minus 2000, for the WRF 4 km Mexico domain.
Figure 8: (left) monthly mean temperature (°C) for February 2050 and (right) the difference between
the February monthly mean temperatures for 2050 minus 2000, for the WRF 4 km Colombia
domain.
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Figure 9: (left) monthly total precipitation (mm) for February 2050 and (right) the difference
between the February monthly total precipitation for 2050 minus 2000, for the WRF 12 km domain.
The boxes indicate the locations of the 4 km domains for Mexico and Colombia.
Figure 10: (left) monthly total precipitation (mm) for February 2050 and (right) the difference
between the February monthly total precipitation for 2050 minus 2000, for the WRF 4 km Mexico
domain.
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Figure 11: (left) monthly total precipitation (mm) for February 2050 and (right) the difference
between the February monthly total precipitation for 2050 minus 2000, for the WRF 4 km Colombia
domain.
PREVIOUS STUDIES
In a previous study (funded by the U.S. Agency for International Development), Oglesby
et al. (2005; 2009) used the MM5 regional model (a precursor to WRF) to investigate
climate change in southern Mexico and Central America during the 21st century. They
evaluated and compared the effects of climate change due both to global increases in
GHG and to local deforestation. A nested domain approach was used. That is, a large
outer domain at a fairly coarse resolution of 36 km ranged from the central Pacific to the
Central Atlantic, and from the southern United States to south of the equator. Inside this
larger domain was nested a domain at a horizontal resolution of 12 km that encompassed
all of Central America (and southern Mexico) and adjacent ocean regions. While this
inner domain resolves the mountainous terrain fairly well, even it is too coarse to capture
all meaningful physiographic and surface features.
Global warming
The GHG model runs were based on IPCC-mandated ‘21st century’ simulations, from the
Third Assessment Report (TAR) (2003). In order to evaluate short-term changes, models
were run for 2010, 2015, and 2025. In order to evaluate longer-term changes, models
were run for 2050 and 2099 (model runs for 2005 serve as a present-day control). The
IPCC ‘business as usual’ (BAU) A2 scenario was chosen. This scenario assumes no
attempts are made to limit greenhouse gas emissions, and therefore has the largest
increase occurring over the 21st century. The BAU was chosen specifically because it is a
‘worst case’ scenario, that is, will provide the largest possible climate changes that could
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be expected. Use or consideration of the IPCC ‘weak stabilization’ or ‘strong
stabilization’ scenarios should produce smaller climatic changes.
Figure 12 shows simulated surface temperature and precipitation differences between
2005 and 2050 under the A2 scenario. A warming is seen almost everywhere; this is
largest (up to 5°C) where the land mass is largest (e.g., south Mexico, Guatemala, and
Honduras) and smaller (generally 1°C or less) where the land mass is smaller (e.g., Costa
Rica and Panama). Precipitation generally decreases along the Caribbean coast, due to a
reduction of the trade winds in this very moist region, but shows little change to small
increases elsewhere. The overall conclusion is that Central America becomes warmer and
more humid, with less precipitation in currently wet regions, and more where sufficient
precipitation is currently problematical.
Figure 12: (left) Surface temperature differences (in °C) and (right) precipitation differences (in %)
for September monthly average for 2050 minus 2005 (after Oglesby et al., 2009).
Deforestation
Two runs were made using MM5 to evaluate the impact of extreme deforestation on
climate. One run had all of Mesoamerica containing evergreen forest, with the other all
grassland. Replacing trees with grassland has two major effects: 1) An increase in albedo,
leading to cooling and stabilization of the atmosphere. 2) A large reduction in
evapotranspiration from the surface, leading to warming and stabilization of the
atmosphere. In terms of temperature change, the decrease in evapotranspiration
overwhelms the increase in albedo, leading to overall warmer surface conditions. But
both processes tend to stabilize the atmosphere and reduce precipitation. Other more
minor effects also occur, such as a reduction in surface roughness when grassland
replaces forest, which affects winds, and also inhibits evaporative fluxes from the
surface.
The climatic impacts of this complete deforestation are shown for the wet season in
Figure 13. Warmer and drier conditions occur in both the dry and wet seasons, but the
impact is much larger in the wet season for both temperature and rainfall. Temperatures
warm by 1-2°C during the dry season, and precipitation generally shows a modest
decrease, though of course for most of Mesoamerica precipitation is very light during this
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Figure 13: Difference between a run with all evergreen forest and a run with all grassland in surface
temperature (top) and precipitation (bottom) for the month of September 1998 (after Oglesby et al.,
2009).
time anyway. During the wet season, on the other hand, temperatures increase by up to
4-6°C, and precipitation is reduced by up to 30%. These changes are largest where the
land masses are large, and smallest over Panama and Costa Rica, where land masses are
smaller and hence closer to the ocean. This is an expected result as the larger the land
mass, the larger the change in forest cover and the less the ameliorating effects of
adjacent oceans.
Importantly, the simulated climate changes for Mesoamerica due to global warming are
far smaller than those from those due to complete deforestation versus complete forest
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cover. Though both sets of results are preliminary, if this conclusion holds up when more
thorough studies are completed, the implication is that the countries that comprise
Mesoamerica should be far more concerned with the effects of deforestation than global
warming.
IMPLICATIONS AND FUTURE WORK
Analyses from the global and regional climate models both suggest warming of a few
degrees Celsius for all of Mesoamerica, with changes greatest in the continental interiors,
and least near coastal regions and in the mountains, the regional model results provide
much more detail on how local topography and land use affect temperatures, and how
they may change. Precipitation is another matter, as the regional models suggest that the
global model results may be unreliable, due to the inability of the latter to adequately
resolve topographic effects. In particular, the IPCC conclusion that precipitation will
decreases for much of Central America is questioned. It is possible that much of the
region will see little change, or even an increase.
In a previous study (funded by the U.S. Agency for International Development), we used
the MM5 regional model to investigate climate change in southern Mexico and Central
America during the 21st century. Importantly, the simulated climate changes for
Mesoamerica due to global warming were far smaller than those from those due to
deforestation.
As the evolving nature of this document itself demonstrates, generating regional climate
change impacts scenarios for Mesoamerica is an ongoing process. Plans should be laid
now to utilize the next generation IPCC Fifth Assessment Report (AR5) information.
Potential regional causes of climate change such as due to land use changes also need to
be investigated more thoroughly.
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University Press, Cambridge, United Kingdom and New York, NY, USA, 881pp.
IPCC (2007) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the
Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin,
M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge
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Nakićenović, N., and R. Swart (eds.) (2000) Special Report on Emissions Scenarios. A Special Report of
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Cambridge, United Kingdom and New York, NY, USA, 599 pp.
Oglesby R.J., D.J. Erickson, J.L. Hernandez, D. Irwin (2005) Coupled global-regional climate model
simulations of future changes in hydrology over Central America. Paper presented at the AGU Fall
Meeting, San Francisco, December.
Oglesby, R.J., T.L. Sever, W. Saturno, D.J. Erickson, and J. Srikishen (2009) The collapse of the Maya:
could deforestation have contributed?, Journal of Geophysical Research, in press.
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