Central America: Vulnerability Assessment to Climate Change for the Water, Coastal, and Agricultural Resources

Central America Country Studies Project Team

SUMMARY: Based on the most recent scientific knowledge from global assessments on climate change and the necessity for decreasing the regional uncertainties that still exist on the issue, studies for estimating the vulnerability of water, agriculture, and coastal resources to a change in climate are being conducted in Central America. Seven countries (Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama) participate in the initiative coordinated by the Regional Committee in Hydraulic Resources (CRRH) and the Central America Commission on Environment and Development (CCAD). The Government of the United States of America through its Country Studies Program (U.S. CSP) is supporting the effort. Several methodological discussions and consultations have been held between scientists from Central America and the U.S. CSP.

The project was initiated in January 1994 and after finalizing organizational matters and training for the 29 studies included within the region, several teams of specialists are now working on the assessment. Due to the fact that seven countries are involved in the project and that the schedule of activities varies for each area of study, it is still premature to make comparisons other than on methods and activities. Baseline scenarios are being developed for the region. They cover socioeconomic, environmental, and climatological aspects of the region. Each country has discussed and selected priority areas and actions to serve as the focus of the study, through "National Development Plan" criteria.

For the water resources sector estimations of climate change impacts on demand and supply of water are being completed. A video mapping analysis of the Pacific coastline of Central America and for the Caribbean coastline of Honduras and Belize has been completed to identify the vulnerability of coastal resources. For the agricultural sector, all basic data have been gathered to complete the model simulations of climate change impacts for subsistence crops.

INTRODUCTION

Scientific estimations indicate that changes in the global temperature may have an effect on the intensity and frequency of tropical cyclones affecting Central America. Changes in the Intertropical Convergence Zone, and in the speed and seasonality of the trade winds may also be expected. A modification in these systems would change the actual climate regime of Central America. According to the scientific assessment of the Intergovernmental Panel on Climate Change (IPCC) (Houghton, et al., 1990), a change in the actual climate conditions, may have an effect on important economic activities, such as: forestry, biodiversity, water resources, agriculture, human health, and coastal and marine ecosystems.

Even though the growing importance that new activities like tourism have had recently, agriculture is still a major component in the economy of the Central American countries. Agriculture is important for the region not only for economic income purposes (cash crops) but also from the perspective of subsistence and food security. The high dependence of the Central American economies on agricultural products and the corresponding relationship between this sector and the climate, increases the sensitivity of this sector to a potential change in climate.

In most of the Central American countries the production of energy depends, on a high percentage, of its hydroelectric capacity. Changes in the circulation patterns that might affect the seasonality and the amount of rainfall would present a major threat to the energy production sector. Recent experiences with the El Niñ o Southern Oscillation (ENSO) phenomenon are evidence of this vulnerability.

Central America, located in the middle of the American Continent is natural divide between two oceans, therefore, it contains one of the richest and more diverse coastal and marine systems of the world. These systems include coral reefs, mangroves, and one of the largest continuous beaches in the world.

Potential problems associated with the sea level rise and the increasing development of tourism and commercial infrastructure along the coast, place the countries' economies in a vulnerable condition.

Forest and wildlife are critical assets for Central America. They are important not only for activities like ecotourism, but also as a natural laboratory for finding new medicines and place for the species to live in this human saturated world.

From a global perspective, the tropical forests of Central America play a large role as a sink of greenhouse gases from the atmosphere. A high percentage of these forests are under some kind of protective law.

New initiatives from governments are addressing all of these valuable resources within a general sustainable development framework. Given the importance that natural resources have for Central America and the high dependence that exist between the resources, climate, and economic growth, a regional study is being undertaken for assessing the vulnerability of water, agriculture, and coastal resources to a potential change in climate.

METHODS

The methodology used for the assessment of the vulnerability of the water, coastal, and agricultural resources to a change in climate for Central America can be divided into four components:

1. Baseline scenarios
‹ Socioeconomic scenarios
‹ Environmental scenarios
‹ Climate scenarios
2. Vulnerability of water resources
3. Vulnerability of coastal resources
4. Vulnerability of agricultural resources

Baseline Scenarios

Socioeconomic
Scenarios for income growth, population growth and distribution, energy demand, and agriculture demand are being prepared for the Central America region contemplating projections to the year 2075. General estimations based on global and regional sources (Pepper, 1992; United Nations, 1989,1990) are being used.

Environmental
Environmental scenarios are being prepared with projections to the year 2075 considering the following factors: land-use change (including deforestation and urban development), tenure, erosion and use of pesticides.

Climate
The subgroup for climate scenarios is developing the scenarios using information generated from the General Circulation Models (GCMs) and from the Central America reference data base on climate change, which have been developed for the activities of the IPCC.

The main methodological steps include:
€ Development of the Central America reference data base on climate change
‹ Criteria for information selection
‹ Selection and collection of information
‹ Input and transferring of information to data base
‹ Quality control
‹ Development of data base
€ Study of available results from GCM models
‹ Comparative analyses between the pressure, temperature, precipitation and solar radiation fields with the actual fields (Hastenrath, 1981)
€ Establishments of regional characteristics for validating the results from the models
€ Selection of the models used for the development of the scenarios
€ Development of scenarios.

Water Resources

The main methodological steps include:
€ Selection of main study areas (basins) according to criteria
€ Impacts on the water resources (supply)
‹ Gathering and quality control of information
‹ Analysis of information
‹ Determination of the monthly availability of the water using the CLIRUN 3 model
€ Impacts on the use of water (demand)
‹ Determination of the actual use of water
‹ Verification of information
€ Estimation of the water demand for the year 2075, for each basin, with no change in climate
€ Vulnerability
‹ Balance between supply and demand for each basin under study
‹ Determination of the level of vulnerability by using the criteria developed by Shuval (Shuval,1987)

Coastal Resources

The main methodological steps include:
€ Gathering of basic information (maps)
€ Development of criteria for establishing priority zones for coastlines
‹ Government and private sectors consultations (national plans for development and coastal zone management plans)
€ Preliminary classification of coastline
‹ Expert judgement and national documents
€ Videotaping of coastline
€ Video analysis
€ Coastline classification update and calibration according with video
€ Making ground truth measurements for priority zones
€ Development of coastline profiles for priority zones
€ Estimation of vulnerability for priority zones

Agricultural Resources

The main methodological steps include:
€ Identification of sensitive crops (highly climate- dependent) in the region
€ Definition of zones
€ Definition and collection of information
€ Model validation (DSSAT 3.0)
€ Simulations of crop growth
€ Estimation of vulnerability

DISCUSSION

Baseline Scenarios

Socioeconomic and environmental scenarios are being developed for the Central American region and in certain cases individually for each participating country depending on the availability and quality of the information that is available.

Final results from this component are expected in April 1995.

Climate Scenarios

Agricultural information will be handled independently for each participating country.

A Central American reference database for climate change studies is under development. Climatological and hydrological data for the region is being input into the system. At this moment, 80 percent of the data entry process has been completed. Data includes daily precipitation, daily maximum and minimum temperature, daily solar radiation and/or sunshine hours, monthly river flow and runoff. The information covers the period 1951‹ 1994, and for some areas earlier records have been obtained, some of them starting in 1886. A total of 60 weather stations were selected for Central America. They are representative of large climatological zones and of the main synoptic patterns that produces the actual regional weather and climate.

In the case of hydrological and agronomic information, the data represent specific basins and zones were the studies are taking place (Tables 1 and 3).

All the information entered in the data base has been subject to a quality control process. Two main approaches are being used for the development of climate scenarios for the vulnerability studies: one is a selection of those model results that best represent the Central American region climate. The other approach is more subjective since it incorporates the expert judgement. On the basis of the model results that best represent the region, climatologists and meteorologists from the region will incorporate their knowledge of the synoptic systems and their corresponding mesoscale impacts. This latter approach will allow for a better utilization by the scientists who are in charge of assessing the vulnerability in specific zones of Central America.

The generation of climate scenarios is expected to be completed by April 1995.

Water Resources

Each of the seven countries participating in the study has identified the main basins to be studied (Table 1). They were selected based on their national plans for development, and taking into account their actual and potential relevance for water supply and hydroelectricity. In some cases irrigation uses were also considered. At this moment each country is working on the analysis of the supply by applying the CLIRUN 3 model. The results from this phase of the study will be discussed in a workshop that will take place in Panama City on April 5‹ 7, 1995.

Coastal Resources

For the estimation of the vulnerability of the coastal resources, priority zones have been established (Table 2) and the basic information has been collected and analyzed in order to classify and characterize the coastline of Central America. A video tape shot from two altitudes (average 50 and 250 m) has been prepared for the Pacific coastline of Central America and for priority areas of the Caribbean coastline.

At this point, coastline profiles are being prepared and ground truthing is being completed. It is estimated that 80 percent of the task has been completed.

Agricultural Resources

The more sensitive crops selected for the study were maize, beans, and rice as food security crops, and banana and coffee as cash crops. The zones of study are presented in Table 3.

At this point each national team is gathering the information and preparing the simulations with the DSSAT3 model.

REFERENCES

Hastenrath, S., and P. Lamb. 1981. Climatic Atlas of the Tropical Atlantic and Eastern Pacific Oceans. The University of Wisconsin Press.

Houghton, J.T., Jenkins, G.J., and J. J. Ephraums. 1990. Climate Change: The IPCC Scientific Assessment. Intergovernmental Panel on Climate Change.

Pepper, W. et al., 1992. Emissions Scenarios for the IPCC. An update: Assumptions, Methodology, and Results. ICF Incorporated, Fairfax, VA., U.S.A.

Shuval, H.I. 1987. The Development of water reuse in Israel. Ambio 16:186‹ 192.

United Nations. 1990. Overall Socioeconomic Perspective of the World Economy to the year 2000, New York, N.Y., U.S.A.

United Nations. 1989. World Population Prospects 1988, New York, N.Y., U.S.A.


INTERIM REPORT ON CLIMATE CHANGE COUNTRY STUDIES
March 1995

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