1998 Year of the Ocean Impacts of Global Climate Change 



During normal years, winds along the equator and along the coast of Peru and the west 

 coast of North America, push surface waters offshore bringing cold, nutrient rich waters from 

 below to the surface — a process known as upwelling. These cold, nutrient rich waters stimulate 

 plant growth resulting in well-established plankton populations and the species which feed on 

 them that include fish, birds, and marine mammals. During El Nifio periods, the winds change, 

 upwelling decreases, and the normal plankton population decreases. The animals which feed on 

 the plankton either move elsewhere or die. For example, the 1972-73 El Niiio coupled with 

 overfishing caused a collapse of the anchovy fishery off Peru. In addition, in the Pacific 

 northwest. El Niiio leads to changes in the salmon fisheries. This is linked to more northward 

 migration of mackerel which prey on juvenile salmon. 



ENSO episodes can now be predicted to a level of skill and with enough lead time that 

 hundreds of millions of dollars a year can be saved both in the U.S. economy and abroad. A 

 recent interdisciplinary study estimated the value of improved ENSO forecasts to U.S. 

 agriculture to be between $240 and $325 million per year. A draft study estimates the benefits of 

 a perfect forecast in crop storage to be $240 million aimually for com alone. Advanced 

 knowledge of ENSO will allow farmers to make decisions to maximize agriculture yields. ENSO 

 forecasts have the potential to improve fisheries management because ENSO episodes strongly 

 influence marine catches from Chile to Alaska. In addition, ENSO-induced changes in 

 precipitation can lead to increases in the threat of mosquito-borne diseases such as malaria. The 

 U.S. Centers for Disease Control and Prevention and the World Health Organizafion are building 

 programs to utilize climate forecasts for enhanced health surveillance and early-warning 

 systems. 



Benefits to the water resources and energy sectors are potentially large. The availability 

 of fresh water for irrigafion and household use is fiindamental to economic well being and varies 

 dramatically during ENSO episodes. ENSO episodes have been linked to regional droughts and 

 an increase in the number of forest fires due to decreased precipitation. Decisions on the 

 purchase and distribution of fuels could be made more cost effective, or estimates of fuel demand 

 based on anticipated climate trends could contribute to more efficient decisions regarding options 

 for purchasing different energy supplies. 



To produce useful seasonal to interannual climate forecasts, it is necessary to implement 

 an operational climate forecasting system. It is also necessary to continue to invest in process and 

 modeling research that leads to improved predictability of temperature and precipitation. In 

 addition, enhanced global observing and data processing systems will continue to be required to 

 support the research and to initialize and validate model predictions. 



Status of the Relevant Science and Technical Base 



Because of limited observational capabilities before the 1980s, it was not even possible to 

 know if an El Nino episode was underway until several months after the episode began. Progress 

 in climate prediction in the 1980s and early 1990s has been stimulated by the development of 

 models used for ENSO prediction, by empirical and theoretical studies to better understand the 



G-13 



