ABSTRACTS - CLIMATE CHANGE AND LATIN AMERICA

Latin America-Wide Reports

Jones, Peter G., and Philip K. Thornton. 2003. "The potential impacts of climate change on maize production in Africa and Latin America in 2055," Global Environmental Change, Vol. 13, No. 1, pp. 51 - 59.
ABSTRACT: The impacts of climate change on agriculture may add significantly to the development challenges of ensuring food security and reducing poverty. We show the possible impacts on maize production in Africa and Latin America to 2055, using high-resolution methods to generate characteristic daily weather data for driving a detailed simulation model of the maize crop. Although the results indicate an overall reduction of only 10% in maize production to 2055, equivalent to losses of $2 billion per year, the aggregate results hide enormous variability: areas can be identified where maize yields may change substantially. Climate change urgently needs to be assessed at the level of the household, so that poor and vulnerable people dependent on agriculture can be appropriately targeted in research and development activities whose object is poverty alleviation.

Baethgen, Walter E. 1997. "Vulnerability of the agricultural sector of Latin America to climate change," Climate Research, Vol. 9, No. 1-2, December 29, pp. 1-7.
ABSTRACT: The vulnerability of the agricultural sector in any region to future possible climate-change scenarios is determined to a great extent by the vulnerability of the sector to current climatic, economic and policy scenarios. Agricultural systems which are currently subject to extreme climatic interannual variability (drought, flood, storms, etc.) are likely to become even more vulnerable under the most commonly expected scenarios of climate change (i.e. increased temperatures, increased rainfall variability). Similarly, agricultural systems which are currently subject to drastic changes in economic and policy scenarios are also prone to become more vulnerable under expected climate-change conditions. The agricultural sector of Latin America has been subject to important variations in economical conditions and policies. These conditions have affected the structure of agricultural production, and resulted in a large reduction of the number of small farmers, who have migrated to poor metropolitan areas. Even for larger, commercial farmers, unstable and often inconsistent agricultural policies have increased the vulnerability of the sector. Additionally, large areas of Latin America are already affected by current interannual climatic variability related to the length of rainy seasons and the occurrence of extreme events (droughts, floods, etc.). The few studies conducted in the region to specifically assess the impact of climate change on agriculture have revealed expected reductions and increased variability in crop productivity. Similar results should be expected in the vast regions devoted to livestock production, since the systems are based on a fragile balance of nutrients, available water, stocking rates and pasture species. The characteristics of the current situation described in this article demonstrate the vulnerability of Latin American agriculture to climate change. Preparing the agricultural sector to mitigate the potential negative effects of climate change will require strong and consistent efforts in both the scientific and policy sectors of the region.

Yates, David N. 1997. "Climate change impacts on the hydrologic resources of South America: an annual, continental scale assessment," Climate Research, Vol. 9, No. 1-2, December 29, pp. 147-155.
ABSTRACT: Two empirical annual runoff models which represent point estimates of river basin discharge were used for assessing the potential impact of climate change on runoff over South America. The first model is an annual regression relationship which relates temperature and precipitation to basin discharge. The second relationship is based on observed climatological variables and relates annual precipitation and potential evapotranspiration to runoff. A Geographic Information System (GIS) was used to implement these annual models in order to assess runoff on a 0.5° [lozenge] 0.5° grid over South America using mean annual temperature, precipitation, and computed potential evapotranspiration images. Annual changes in precipitation (percent change) and temperature (absolute change) were gathered from 4 Global Circulation Models (GCMs) and were used to derive new runoff estimates. Generally, these climate change scenarios consistently showed increases in runoff over the northwest and southern regions of South America, while the central and northeast regions were a mixture of increases and decreases depending on the GCM scenario. Comparisons with detailed, basin level models with shorter time-steps are necessary to validate the use of these annual approaches for continental scale assessment.

Country-Level Studies

Argentina

Díaz, Raúl A., Graciela O. Magrin, María I. Travasso, and Rafael O. Rodríguez. 1997. "Climate change and its impact on the properties of agricultural soils in the Argentinean Rolling Pampas," Climate Research, Vol. 9, No. 1-2, December 29, pp. 25-30.
ABSTRACT: The agriculture of the Argentinean pampean region is undergoing a reconversion process as a result of a more intensive use of agrotechnologies. The ongoing changes are likely to overlap with the greenhouse warming-related climatic changes and atmospheric CO2 increase predicted for the next century. The goal of this study is to assess the potential impact of such changes on certain properties of soils of the Rolling Pampas, which support 10 to 15% of the national grain crop and oilseed production. Rotation of wheat/soybean-maize crops in 45 agricultural soils was simulated using the EPIC model (Erosion/Productivity Impact Calculator; US Dept of Agriculture), which was previously calibrated and validated for local conditions, for the 1996 to 2050 period under 2 scenarios: (1) no climate change, and (2) climate change conditions derived from regional climate parameters projected by the GISS general circulation model combined with a CO2 concentration of 550 ppm. The 1971 to 1995 period was simulated under neutral conditions with the purpose of defining soil conditions for 1996. It was found that in the event of a change in climate, physical proporties would change to a lesser degree than chemical properties. The soil bulk density would decrease by 8% with respect to the baseline scenario in soils under risk of erosion. In contrast, since it was assumed that the erosive storm pattern would remain unchanged, there would be no variations in the erosion rate. A general decrease in potential soil fertility of 6 to 10% for total organic N and 7 to 20% for organic C would take place after a 55 yr period. The sustainability of certain soils of the Carcarañá River basin, particularly the Villa Eloísa series, would be at a higher risk.

Magrin, Graciela O., María I. Travasso, Raúl A. Díaz, and Rafael O. Rodríguez. 1997. "Vulnerability of the agricultural systems of Argentina to climate change," Climate Research, Vol. 9, No. 1-2, December 29, pp. 31-36.
ABSTRACT: Agricultural production is one of the pillars of the Argentinean economy. The contribution of this sector is expected to keep growing in the near future as a consequence of the current technological development trend. However, the projected changes in climate and in the atmospheric concentration of CO2 in the coming years is likely to affect the productivity of crops, thus causing an impact on the national economy. This paper addresses climate change impact on the production of the main crops of the Argentinean pampean region by means of crop growth and development simulation models for wheat, maize and soybean included in DSSAT v. 3.0 (Dension Support System for Agrotechnology Transfer, Univ. of Hawaii, Honolulu). The weather data used includes temperature, global solar radiation and precipitation values from 23 sites within the region (current climate conditions) and the corresponding GISS general circulation model projections for the year 2050 (future climate) with CO2 concentrations of 330 and 550 ppm respectively. According to the results obtained, a generalized increase in soybean yield and a decrease in maize yield would occur. Wheat yield is likely to increase in the southern and the western parts of the region and decrease towards the north. Wheat and soybean production in the pampean region would increase by 3.6 and 20.7% respectively, while maize production would be reduced by 16.5%.

Carril, Andrea F., Moira E. Doyle, Vicente R. Barros, and Mario N. Núñez. 1997. "Impacts of climate change on the oases of the Argentinean cordillera," Climate Research, Vol. 9, No. 1-2, December 29, pp. 121-129.
ABSTRACT: Until the mid 1970s a negative trend in the river flow values in the Argentinean provinces of San Juan and Mendoza (Cuyo region) was observed. The prevailing critical conditions and their economic and social impacts provide a basis for the characterization of an adverse climate change scenario for the region. The causes of the early 1970s scenario were assessed in this study in order to determine whether or not it could be related to global warming conditions. River flows are dependent on winter precipitation and on accumulated snow on the Andes cordillera. The lowest negative river flow value observed can be explained by the behaviour of the Southern Oscillation Index (SOI) and other macroclimatic parameters, such as sea-surface temperatures (SSTs) of the Atlantic and Pacific oceans. It was observed that the SOI is the parameter most strongly correlated with river flows. The highest correlation was found for the 2.4- and 4.8-yr frequencies and the low 43-yr frequency. Consequently, the low river flow values observed during the early 1970s are considered to be related to a low-frequency minimum of the El Niño-Southern Oscillation (ENSO), as well as to the behaviour of sea-surface temperature close to the coast of Chile. Both factors are associated with a minimum hemispheric temperature value. It is concluded that the 1960-70 drought in the oases of the cordillera was not linked to a warm period. Therefore it is not appropriate, at least for the time being, to state that the oases will experience drought conditions under a global warming scenario with temperature increases of a few degrees.

Cuba

Centella, Abel, Tomás Gutiérrez, Miriam Limia, and Roger Rivero Jaspe. 1999. "Climate change scenarios for impact assessment in Cuba," Climate Research, Vol. 12, No. 2-3, pp. 223-230.
ABSTRACT: Determining seasonal and regional patterns of climate change is in growing demand for the assessiment of the potential impacts on climate-related economic activities, such as agriculture or water resource management. This paper presents the results of the work done to determine possible patterns of CO2-induced climate change in Cuba based on the IPCC's best estimate of climate sensitivity and using IS92a and KYOTOA1 emission scenarios. The climate change scenarios were prepared combining general circulation model (GCM) results and output from the MAGICC climate model. The results of this study show that the methodology and the GCMs selected provide a large range of regional climate change and guarantee that the climatic change scenarios developed can be applied to explore a wide spectrum of the potential climate changes in different environments and social sectors in Cuba.

Mexico

Magaña, Víctor O., and Cecilia Conde. 2000. "Climate and Freshwater Resources in Northern Mexico: Sonora, a Case Study," Environmental Monitoring and Assessment, Vol. 61, No. 1, March, 167-185.
ABSTRACT: An analysis of current trends in water availability in the Mexican border state of Sonora is presented to illustrate what may be faced under climate change conditions. Precipitation, streamflow and even dam levels data are examined to estimate what changes have been experienced in recent decades. There are indications that the more frequent occurrence of El Niño/Southern Oscillation (ENSO) events have resulted in more winter precipitation and consequently in a slight increase in water availability in northwestern Mexico. However, water demands grow much faster than such trends in water availability, mainly due to a rapid increase in population in urban areas and in socio-economic activities such as those related to agriculture, industry and power generation. Some strategies to adapt or mitigate climate change conditions are proposed.

Villers-Ruíza, Lourdes, and Irma Trejo-Vázquez. 1998. "Climate change on Mexican forests and natural protected areas," Global Environmental Change, Vol. 8, No. 2, July, pp. 141-157.
ABSTRACT: In order to determine the vulnerability of Mexican forest ecosystems, natural protected and forestry areas to climate change, an assessment was performed under two climate change scenarios generated by the Canadian Climate Center (CCC) and the Geophysical Fluid Dynamics Laboratory (GFDL) models. Based on Holdridge's life zones and local classifications, the results suggest that the most vulnerable life zones would be temperate cold and warm forests, mainly due to the increase in temperature. Tropical dry, very dry and thorn forests would enlarge their current area coverage under the climate change CCC scenario, while under the GFDL scenario increases in the distribution of tropical humid and wet forests would occur. For some ecosystems, such as tropical forest, climate change is a minor threat compared to the degradation currently induced by human activities. A current land-use assessment indicates that, in the recent years, the ecosystems most affected by human activities are the tropical forests due to the expansion of grasslands for tropical cattle ranching. Man-induced forest fires, to increase pasture production, are the main cause of degradation in temperate forests. The natural protected areas most affected by climate change would be the northern and western regions of the country, as well as the southern tropical mountains where an important number of endemic plants exist. On the other hand, forestry areas that would be most affected are located in the Sierra Madre Occidental, where timber exploitation in coniferous forests is high.

Conde, Cecilia, Diana Liverman, Margarita Flores, Rosa Ferrer, Raquel Araújo, et al. 1998. "Vulnerability of rainfed maize crops in Mexico to climate change," Climate Research, Vol. 9, No. 3, pp. 17-23.
ABSTRACT: The impacts of a potential climate change on rainfed maize crops in Mexico are analyzed. For that purpose, baseline scenarios based on current climate conditions and their relation with maize crop development were created. Climate change scenarios were further developed and the crop vulnerability under each scenario was assessed. Two methods were used to quantify vulnerability. In the first place, maps describing the suitability for crop production according to climate conditions were produced. The differences between the baseline and the climate change scenarios allowed for estimating the area of the country likely to be positively or negatively affected. Secondly, the CERES-Maize model was applied to estimate rainfed maize crop yields at 7 sites in Mexico under the baseline and climate change scenarios. Adaptive measures were proposed and their feasibility was assessed on the basis of a simple cost-benefit analysis.

Villers-Ruiz, Lourdes, and Irma Trejo-Vázquez. 1997. "Assessment of the vulnerability of forest ecosystems to climate change in Mexico," Climate Research, Vol. 9, No. 1-2, December 29, pp. 87-93.
ABSTRACT: An assessment of the vulnerability of forest ecosystems in Mexico to climate change is carried out on the basis of the scenarios projected by 3 climate models. A vegetation classification was performed according to 2 models, the Holdridge Life Zone Classification and the so-called Mexican Classification (a climate-vegetation classification based on typologies developed for Mexico). Projections of climate models were based on a doubled CO2 concentration condition. The models used were: the CCCM, which estimates an average increase in temperature for the country of 2.8°C and a decrease in annual precipitation of 7%; the GFDL-R30, which estimates an increase in both parameters by 3.2°C and 20% respectively; and a sensitivity model in which a homogeneous increase of 2°C in temperature and a 10% decrease in precipitation are applied throughout the country. In general, the cool temperate and warm temperate ecosystems were the most affected and tended to disappear under the conditions of the 3 scenarios. In contrast, the dry and very dry tropical forests and the warm thorn woodlands tended to occupy larger areas than at present, particularly under the conditions projected by the CCCM model. However, under the GFDL-derived scenario an increase in the distribution of moist and wet forests, which would be favoured by an increase in precipitation, was predicted.

Mendoza, Víctor M., Elba E. Villanueva, and Julián Adem. 1997. "Vulnerability of basins and watersheds in Mexico to global climate change," Climate Research, Vol. 9, No. 1-2, December 29, pp. 139-145.
ABSTRACT: Some conclusions on the vulnerability of hydrologic regions in Mexico to future changes in climate can be drawn from the application of regional-scale thermal-hydrological models. Climate changes induced by the doubling of atmospheric CO2 have been predicted for the year 2050 by general circulation models (GCMs) and energy balance models (EBMs). The results obtained suggest that potential changes in air temperature and precipitation may have a dramatic impact on the pattern and magnitude of runoff, on soil moisture and evaporation, as well as on the aridity level of some hydrologic zones of Mexico. However, in other cases climate change is likely to produce a positive effect. Indices were estimated for quantifying the vulnerability of hydrologic regions and of the country as a whole. These vulnerability indices were defined according to criteria previously established for studies of this type. The indices provide information about both the hydrologic zones which are vulnerable even under current climate conditions and others which may be vulnerable to future climate changes.

Liverman, Diana M. and Karen L. O'Brien. 1991. "Global warming and climate change in Mexico," Global Environmental Change, Vol. 1, No. 5, December, pp. 351-364.
ABSTRACT: Climate models suggest that global warming could bring warmer, drier conditions to Mexico. Although precipitation increases are projected by some models, in most cases they do not compensate for increases in potential evaporation. Thus, soil moisture and water availability may decrease over much of Mexico with serious consequences for rainfed and irrigated agriculture, urban and industrial water supplies, hydropower and ecosystems. However, the assessment of global warming impacts in Mexico is an uncertain task because the projections of different models vary widely, particularly for precipitation, and because they perform poorly in reproducing the observed climate of Mexico.

Panama

Espinosa, Daly, Abril Méndez, Irina Madrid, and Raúl Rivera. 1997. "Assessment of climate change impacts on the water resources of Panama: the case of the La Villa, Chiriquí and Chagres river basins," Climate Research, Vol. 9, No. 1-2, December 29, pp. 131-137.
ABSTRACT: The goal of this study is to develop different scenarios of water resource availability in Panama under climate change-induced temperature and precipitation variability, considering a potential doubling of the atmospheric CO2 concentration in the next 100 yr. The water balance model CLIRUN3 was combined with 20 yr of basic climate information records (precipitation, potential evapotranspiration and water flow) to simulate monthly river runoff in the Chagres (Panama Canal) river basin. This basin supplies water to 25% of the country's population and is of great importance for international navigation. In the cases of the Chiriquí and La Villa river basins, 10 yr of records were used. The Chiriquí river basin is the main national source of hydropower, while the La Villa river basin is of agricultural importance. The Chagres river basin is part of the Atlantic watershed while the others belong to the Pacific watershed. The model was calibrated and run for both watersheds under scenarios with temperature increments of +1 and +2°C, while the precipitation changes considered were ±15% for the Pacific and ±20% for the Atlantic watershed. It was observed that the monthly runoff tends to decrease by 3 to 42% of the mean value in both watersheds when temperature increases and precipitation decreases. If both temperature and precipitation increase, the mean runoff value in the Pacific basins will be reduced by 5 to 35% from November to April and increased by 4 to 40% in the remaining months. In the basin of the Atlantic watershed all simulated monthly values are 3 to 50% higher than the actual mean.

Uruguay

Hareau, Annie, Raúl Hofstadter, and Andrés Saizar. 1999. "Vulnerability to climate change in Uruguay: potential impacts on the agricultural and coastal resource sectors and response capabilities," Climate Research, Vol. 12, No. 2-3, pp. 185-193.
ABSTRACT: Uruguay's economy is mostly based on the use of natural resources that are affected by the strongly variable climate conditions to which the country is exposed. Climate changes induced by greenhouse warming are likely to enhance the country's vulnerability to environmental phenomena and are thus a matter of concern. The analyses carried out, particularly regarding crops, grasslands, and coastal resources, have evidenced the need to develop advanced response strategies framed within sectoral development plans. The type and sign of the effect on crop production would vary, depending on the crop involved. Grassland production is likely to be favored by increased temperature conditions, while precipitation deficiencies or increased variability would be detrimental. The predicted changes in sea level, even the most conservative, would put at risk high capital value land and infrastructure along the Uruguayan coast. Since the coast is frequently affected by storms, the overall vulnerability would also be determined by changes in storm patterns. It was observed that while appropriate conditions are encountered at both the technical and political levels to address changes that may affect the agricultural sector, a considerable effort is required to develop integrated coastal zone management plans that combine general and private interests and include responses to climate change.

Panario, Daniel, and Mario Bidegain. 1997. "Climate change effects on grasslands in Uruguay," Climate Research, Vol. 9, No. 1-2, December 29, pp. 37-40.
ABSTRACT: The most significant climax vegetation in Uruguay is a type of grassland commonly known as evergreen prairie. The evolution of the Uruguayan prairie since the days of the first European settlements involved 3 main stages: (1) 'hardening' as a result of the introduction of livestock, (2) 'refinement' by the action of fire and overgrazing, and (3) further degradation, including preferential development of warm-season species, due to persistent overgrazing. Predicted climate changes (seasonal decrease in water availability coupled with increase in both temperature and atmospheric CO2 concentration) are likely to favor, in the short term, even further preferential development of warm-season species. Whether or not this trend will persist in the long term is difficult to predict with confidence because of uncertainties regarding the responses of the different prairie species to variation in atmospheric CO2 concentration.

Víctora, Carlos, Aarón Kacevas, and Héctor Fiori. 1997. "Soil vulnerability in Uruguay: potential effects of an increase in erosive rainfall on soil loss," Climate Research, Vol. 9, No. 1-2, December 29, pp. 41-46.
ABSTRACT: Climate change is likely to modify rainfall patterns and their interaction with the soil. This paper addresses soil vulnerability in terms of soil loss resulting from increases in the amount of rainfall. Four agricultural soils from Uruguay were studied: 2 'Vertisol Rúptico' soils (Typic Pelluderts), 1 'Brunosol Subéutrico Típico' and 1 'Brunosol Subéutrico Lúvico' (Typic Argiudolls). A field rainfall simulator was used to produce rain events of controlled intensity. Three of the soils were exposed to a constant rain of 70 mm h-1, which is the intensity of 30 min erosive rain events with a return period of 2 yr. The remaining soil, which is characterized by a high infiltration rate, was exposed to 140 mm h-1 rain. A 20 mm rainfall was applied on soil previously wet to saturation of the A horizon. The surface was prepared as bare soil seedbed on natural slopes (which are 2 to 5% steep, depending on the soil). The results obtained were corrected for a constant slope according to the Universal Soil Loss Equation (USLE). Soil losses (in kg ha-1) for rainwater depths (amounts) of 5, 10, 15 and 20 mm respectively were: Vertisol (Serie Tala): 25, 136, 273 and 437; Vertisol (Serie Jesús María): 52, 291, 1233 and 2633; Brunosol (Serie Pando): 368, 961, 1725 and 2683; Brunosol (Serie Colonia Brause): 48, 60, 115 and 224. These results are indicative of: (1) a major difference in the degree of vulnerability among soils, and (2) an increase in the soil loss rate as a result of the increase in the amount of applied rainfall. The high sensitivity of the Uruguayan soils to climate-change-induced potential variations in rainfall pattern is thus confirmed.

Saizar, Andrés. 1997. "Assessment of impacts of a potential sea-level rise on the coast of Montevideo, Uruguay," Climate Research, Vol. 9, No. 1-2, December 29, pp. 73-79.
ABSTRACT: In this study, sea-level rise scenarios derived from a potential climate change were considered and the physical impacts on the coast of Montevideo, Uruguay, under each scenario were determined. The Bruun Rule was used to calculate coastal erosion. The impacts under a 'no action' response were first assessed. Land and coastal construction loss as well as the effects on infrastructure, such as the sewer system and the port, were evaluated. Inundation along the streams which discharge at the coast was qualitatively assessed. The associated costs were estimated. In addition, possible active responses were identified and their costs were estimated. Costs and benefits of each response option, including the 'no action' option, are discussed in the paper, concluding on the need for planning of anticipatory measures.

Lorenzo, Eugenio, and Luis Teixeira. 1997. "Sensitivity of storm waves in Montevideo (Uruguay) to a hypothetical climate change," Climate Research, Vol. 9, No. 1-2, December 29, pp. 81-85.
ABSTRACT: Outputs from the application of a simple storm wave generation model using real wind data for several years in the 1980s are compared with simulations representing conditions of a 10% higher wind strength and a 1 m sea-level rise. A numeric wave propagation model (combined refraction-diffraction) is also used to calculate propagation coefficients for waves approaching the Montevideo coast under 2 different scenarios. The first one (baseline scenario) describes the current situation, while the second one reflects a 1 m rise in sea level. The analysis of propagation coefficients is carried out for all directions of the wind waves approaching the Montevideo shoreline, using the most representative wave period and height in each case. As a general conclusion it is observed that, under such a climate change scenario, storm waves would increase in height, while their angle of incidence would remain unchanged.

Venezuela

de Lourdes Olivo, María. 1997. "Assessment of the vulnerability of Venezuela to sea-level rise," Climate Research, Vol. 9, No. 1-2, December 29, pp. 57-65.
ABSTRACT: The goal of this study is to assess the vulnerability of 5 sectors of the coast of Venezuela to potential sea-level rise using the methodology proposed by the Intergovernmental Panel on Climate Change. Sea-level rise resulting from thermal expansion of the oceans and melting of glaciers is viewed as one of the main impacts of climate changes. A 0.5 m rise scenario for the year 2100 was used for this study. A modified version of the Brunn Rule was used to estimate land loss due to erosion. Land loss due to inundation was considered for the case of lowlands. According to the assessments performed, land loss due to erosion in the 5 coastal areas chosen for the study (20.07 km2) would be less than that due to inundation (52.63 km2). Oil infrastructure, urban areas, and tourist infrastructure, all of which are essential to the national economy, would be affected. The areas with more population at risk would be the Costa Oriental del Lago de Maracaibo (eastern coast of Maracaibo Lake) and Costa Oriental del Estado Falcón (eastern coast of Falcón State). The former has the highest capital value at risk, followed by Barcelona-Puerto La Cruz-Guanta. Assuming a 'No Protection' response and a 0.5 m sea-level rise, approximately 131.13 km2 would be lost. If the 'Important Areas Protection' option was implemented, only 86.16 km2 (US$ 15000 million) would be lost. The vulnerability of these coastal areas could be reduced by more appropriate planning and management.