U.S. GLOBEC Poised to Study California Current Ecosystem

The physical and biological dynamics of the California Current System (CCS) are sensitive to natural climate variability on time scales ranging from seasonal to interdecadal, and spatial scales from local to basin-wide. Ecosystem structure is closely coupled to variations in physical forcing, thus sensitivity of the coupled physical-biological system to climate variability implies great sensitivity to climate change. U.S. GLOBEC has produced a Science Plan that suggests a number of hypotheses on how the coupled physical-biological system may respond to global climate change, and lays out a plan for how U.S. GLOBEC will study the CCS with the overall goal of producing predictions and integrated assessments of ecosystem response to climate change.

The Research Program

GOAL: To understand the effects of climate change on the distribution, abundance and production of marine animal populations in the CCS.

APPROACH: To study the effects of past and present climate variability on marine animal populations and to use this information as a proxy for how the CCS may respond to future global warming and global climate change.

Program Elements

Time and Space Scales

The CCS offers excellent venues for climate studies because the climate signals are strong and pervasive, and because regional differences are great. The U.S. GLOBEC research program will focus on variability at several scales:


A successful program in the California Current System will produce the following:

The program in the California Current System will continue to move us toward our long-term goal of producing models that provide integrated assessments of the effect of environmental variability and climate change on ecosystems in the CCS and other marine ecosystems in coastal environments.

If the monitoring and field programs are designed correctly, the data sets collected should provide quantitative assessments of ecosystem structure during a period of five or more years that is likely to span a warm ENSO event. The connection to the larger basin scale variability will be provided by data collected in the tropical Pacific Ocean, e.g., that collected by the Tropical Ocean--Global Atmosphere (TOGA) and World Ocean Circulation Experiment (WOCE) programs. Within the CCS, the models will integrate the observations to provide a more complete picture of the biophysical interactions, while the data sets will continue to provide information useful in continued model validation and improvement. In this iterative fashion, the data sets and models will continue to increase our understanding of the way in which CCS ecosystems respond to large-scale environmental variability, long after the formal end of the program. The monitoring system should also continue to be useful in providing new information, as well as in ongoing model improvements. Some of the biophysical models will be imbedded within coupled ocean-atmosphere climate general circulation models (GCMs) in order to test their ability to reproduce the statistics of the historical and paleoecosystem time series, allowing further identification of model weaknesses and further model improvements. Along with the historical physical, zooplankton and fisheries data, they will permit a description of CCS dynamics and ecosystem response during several past ENSO cycles and the most recent interdecadal regime shift in the mid-1970Ős. When confidence in the biophysical models is established, they can also be imbedded within operational forecast models to provide short and medium range forecasts to the National Marine Fisheries Service (NMFS).

The models and monitoring systems will ultimately allow NOAA to provide managers and policy makers with better information on the role of environmental variability and climate change in determining abundances of living marine resources. Many marine populations in EBCs are especially vulnerable to collapse during El Nino events and other interannual to interdecadal extremes. The U.S. GLOBEC program will provide a more thorough scientific basis for assessments of the potential impact of El Ninos on living marine resources. In addition, the research will provide scientific information needed to analyze the economic impact of ENSOs on marine resources.

Information on the response of the system to decadal variability will also be valuable to managers. EBCs are known for their spectacular fishery collapses, such as the Monterey sardines (1940s) and the Peruvian anchoveta (1970s). Such collapses seem to be an inevitable consequence of inadequate understanding of the resources of the ecosystems. We need (1) improved resource management models based on understanding of qualitative state shifts; and, (2) improved capability to recognize and predict state shifts. It is doubtful that adverse fluctuations in the stocks and related industries can be avoided entirely, but if management were armed with the above knowledge and acted appropriately, it should be possible to reduce the severity and duration of the downturns and their resultant economic and social hardships.

In summary, the models, data sets and monitoring systems developed in this program will directly benefit society. The models will stimulate future scientific inquiries, and will identify the most important components of key ecosystems--those which most require close, continued observation. The models represent the ongoing, integrative element of the program. They are the important beginning of operational, climatic ecosystem modeling--the ultimate need of society in order to understand and manage such ecosystems. This will be the legacy of the U.S. GLOBEC program in the California Current System. (This article excerpted from the Executive Summary of U.S. GLOBEC Report No. 11, A Science Plan for the California Current)

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