CCCC - Exec. Summ.

## Executive Summary

### Introduction

This report summarizes discussions and recommendations for a future research program on Climate Change and the Carrying Capacity (CCCC) of the North Pacific. The material presented in this report is the product of a U.S. GLOBEC workshop held at the Battelle Conference Center in Seattle, Washington, in April 1995. The need for the workshop stemmed from the development of a Science Plan for a international coordinated research effort on Climate Change and the Carrying Capacity, which was approved by the North Pacific Marine Science Organization (PICES), in October 1994. In response to the PICES Science Plan, the U.S. GLOBEC Scientific Steering Committee agreed to support a community-wide workshop to explore issues of the oceanic and coastal domains of the Subarctic Pacific and the Bering Sea relevant to U.S. GLOBEC.

### The Research Program

The central scientific issues to be addressed by the PICES/GLOBEC CCCC program are:

1. Physical forcing: What are the characteristics of climate variability; can interdecadal patterns be identified; how and when do they arise?

2. Lower trophic level response: How do primary and secondary producers respond in productivity, and in species and size composition, to climate variability in different ecosystems of the Subarctic Pacific?

3. Higher trophic level response: How do life history patterns, distributions, vital rates, and population dynamics of higher trophic level species respond directly and indirectly to climate variability?

4. Ecosystem interactions: How are Subarctic Pacific ecosystems structured? Do higher trophic levels respond to climate variability solely as a consequence of bottom-up forcing? Are there significant intra-trophic level and top-down effects on lower trophic level production and on energy transfer efficiencies?

### Recommendations for Initial Activities:

In this document we highlight four broad research questions that focus on physical forcing, lower trophic level response, higher trophic level response and ecosystem interactions. Efforts to define subÐsets of research projects that would advance our knowledge of the North Pacific and Bering Sea system and provide insight to these research questions were identified in each of the regional breakout sessions. Examples of potential projects that could be conducted to address the subÐset of questions were advanced for each of the three study regions (the oceanic and coastal domains of the Subarctic Pacific, and the Bering Sea). These questions could form the basis of Announcements of Opportunity for research at a later date. Key research activities related to these issues included retrospective analyses, development of models, process studies, development of observational systems (monitoring), and data management. If funds could be secured to support this program, the first AO would probably emphasize retrospective, modeling, and monitoring studies.

### Products:

Contributions of a U.S. GLOBEC CCCC program might include:

- The development and/or refinement of coupled bio-physical models that could be used to examine hypotheses regarding potential impacts of climate variability on marine ecosystems.

- Improved knowledge of the impact of climate variability on marine ecosystems of the North Pacific. Specifically, the program could elucidate mechanisms controlling marine populations including commercially important fish species and provide quantitative information that would improve the assessment, conservation and management of our nations valuable marine resources.

- Data sets will be assembled during the program that will provide the basis of future research activities in the region.

- The program will advance our ability to make predictions on the future composition of marine communities which could be utilized in simulation models to assess the impact of human activities in the region.

- Studies of how physical forcing couples to the ecosystem will help scientists to anticipate future ecosystem changes, no matter how the climate evolves. Short-term (seasonal) to long-term (decadal) climate variations seem to impact the biological environment. The interdependence of these climate fluctuations and the nature of the biological responses could serve as proxies for prediction of some aspects of future long-term changes.