New directions in research, new findings and continuing key concerns issues on climate change and water resources Max Campos Regional Committe on Hydraulic Resources-Central America

Water resources and climate change Policy makers Interdisciplinary analyses Lack of information about some parts of hydrological cycle Hydrological views of climate (design purposes) Hydrological cycle Biophysical impacts (man) Environmental & social Impacts cycle for water studies

..... require an interdisciplinary approach comprehensive studies of climate and water issues have omitted the social scientists, producing results that are difficult for decision makers to use particularly in the world of policy development, are the views of hydrologists about climate and its change. Most hydrologic studies of extreme events such as floods and droughts have assumed stationarity of climate over time

the importance of including climatic variability in water resources management), for example: moderate fluctuations in climate may produce major hydrologic changes, and in one case noted that a 25 % increase in precipitation in a basin increased the mean annual runoff by 50-70% policy-makers addressing the impacts of climate change on water resources typically are most aware of views of hydrologists. This can result in confusion and loss of credibility about the issues, and inaction at the policy making levels.

Middle 80s. emphasis research:. the effects on precipitation of CO2 induced global warming.. how climate changes might alter extreme events (droughts and floods).. the relationship of climate alterations and water quality.. development of methods to better ascertain climate, water, and society.

Allee, David J., Leonard B. Dworsky, and Albert E. Utton (1993). Managing Transboundary Water Conflicts: The United States and its Boundary Commissions. AWRA 28th Annual Conference & Symposium, Reno, NV, AWRA. US-Mexico border, Canada. water supply, legal/policy/political issues. Allen, L.H., P. Jones, and J.W. Jones (1985). Rising Atmospheric CO2 and Evapotranspiration. St. Joseph, MI, American Society of Agricultural Engineers: US. CO2 levels, evapotranspiration, agriculture. Anderson, Jeffry L., S. Shiau, and Danny Harvey (1991). Preliminary Investigation of Trend/Patterns in Surface Water Characteristics and Climate Variations. NHRI Workshop, Saskatoon, Canada, National Hydrology Research Institute. unspecified/NA. hydrology/groundwater/river flows. Assel, Raymond A. (1988). Impact of Global Warming on Great Lakes Ice Cycles. The Potential Effects of Global Climate Change on the United States. J. B. Smith, and Dennis A. Tirpak. Washington, DC, U.S. EPA. EPA : Eastern US, Great Lakes. lake level fluctuation/ice cover.

POLICY AND CLIMATE CHANGE W ho are the policy makers in water resources? A variety of levels: -local -states and provinces -national level -international level.

POLICY AND CLIMATE CHANGE Needs for Information related to climate change by policy makers: More frequently asked questions being asked by policy makers: 1- what type of climate change is apt to occur?: -Will the variability of weather increase? -Will the mean or modal values of temperature, precipitation or other critical variables change? -What conditions will be altered and by how much? - Will there be more extremes with the normals not changing?

POLICY AND CLIMATE CHANGE 2- Are the changes beyond the stationarity assumptions that hydrologists typically consider in their current designs? -Can we prove or reasonably establish that the changes which may occur in the climate are greater than what has been assumed out of study of the historical records? 3- Can the presumed future changes be predicted (beginning, continuance and/or end? -What is the certainty of the situation? -What are the confidence bands and the probabilities for that the climate change will occur? -Credibility of the information from the scientific community: divergence of opinion between the scientific community leads to inaction by the policy makers.

POLICY AND CLIMATE CHANGE 4- How serious will the change be? -Who is affected, the cost, the social disruptions and an environmental impact - what is affected; - -what is the time reaction of the effect? 5- What are the potential solutions? Scientists should not present problems unless they also help us with their solutions. It implies information on potential adjustments:

GUATEMALA BELICE EL SALVADOR HONDURAS NICARAGUA COSTA RICA PANAMA 522,000 km 2 30 Millones hab.

NOVIEMBRE a FEBRERO EL NIÑO

Areas propensas a sequía en Centroamerica. Ramírez P., Amenazas Hidrometeorológicas en Centroamerica.. Informe consultoría IRG. El fenómeno de El Niño produce una reducción importante en la lluvia del Pacífico Centroamericano la cual puede ocasionar condiciones de sequía en algunos sitios específicos. A pesar de esto, El Niño solamente explica un porcentage de los eventos secos del Istmo.

Resultados del Ier Foro Climático Junio-2001, Tegucigalpa, Honduras, NOAA-OGP, CRRH/SICA

CHANGES IN YEARLY RAINFALL Results from Costa Rica – The Netherlands Climate change project Minister for Environment and Energy (MINAE) National Meteorological Institute (IMN) <800 < Rainfall in mm

CHANGES IN MEAN TEMPERATURE COSTA RICA T>30 C 30 >T> >T>25 25>T> >T>20 Mean temperature for year 2100 Based on model HADCM2 and IS-92a scenario. Actual mean temperature Nat. Met. Institute-CR. Actual mean temperature Nat. Met. Institute-CR. Results from Costa Rica – The Netherlands Climate change project Minister for Environment and Energy (MINAE) National Meteorological Institute (IMN)

CHANGES IN RAINFALL NICARAGUA Rainfall (mm) – year 2100 HADCM2 model and IS92-a Scenario (MARENA 2000) Rainfall (mm)-average (INETER 2000) Important reductions in precipitation are expected along the Pacific region of Nicaragua under IS-92-a: 2010………… -8.4% 2030……..… -14.5% 2050……… % 2070……… % 2100……… % INETER: Instituto Nicaraguense de Estudios Territoriales MARENA: Ministerio del Ambiente y Recursos Naturales

OBJETIVO: Comprender la respuesta hidrológica de las principales cuencas hidrográficas a diferentes escenarios de cambio climático. Criterio de selección: alto potencial de de generación hidroeléctrico, importantes fuentes de abastecimiento de agua para comunidades urbanas y rurales

METODOLOGIA: (Programa de los Estados Unidos para el Cambio Climático (US-CSP) y Expertos en hidrología y meteorología Centroamericanos (PCCC)) Utilización del modelo CLIRUM 3 (precipitación-escorrentía) para simular las variaciones en la escorrentía generada por precipitaciones derivadas de varios escenarios climáticos. Fases: Manejo de información hidro-meteorológica básica. Calibración y validación del modelo CLIRUM 3 (balance hídrico). Estimación general de la vulnerabilidad de las cuencas seleccionadas ante cambios de precipitación y temperatura (estimación de la sensibilidad). Información básica: Ecurrimiento superficial, temperatura, precipitación y evapotranspiración potencial.

PANAMA

120 cuencas principales-23 cuencas transfronterizas – 10.7% mundo 40 % del territorio regional ~ km2 > cualquier país región Capitales en cuencas transfronterizas: Managua-Cuenca río San Juan-Nicaragua Tegucigalpa-Cuenca río Choluteca-Honduras San Salvador – Cuenca río Lempa-El Salvador

Magnitud of the impact of hurricane Mitch 3.5 million were affected. 53% were children under 5. The most affected sector of population was the poorest. Total amount of damages US$ 6,018 M.

Effects on regional GNP: -2.5%

After the lost decade of the 80s, Central American countries were making important progress in: ãConsolidation of democracy. ãStrengthening the integration process. ãOrganizing their economies. ãIntensification of the intra regional commerce. ãMore efficient insertion in the international economy. Central America before Mitch