Introduction

1. Introduction Climate Future: Science and Policy Randall M. Dole NOAA-CIRES Climate Diagnostics Center Mountain Climate Sciences Symposium Lake Tahoe, CA May 25, 2004

2. A Key Symposium Goal Key Symposium Goal Develop support for long-term, interdisciplinary, integrated climate and climate-related research and monitoring in the western mountains. How might this accomplished in the present budget environment?

3. Suggested strategies for success Strategies for Success 1) Make explicit connections to goals in the Climate Change Science Program (CCSP) strategic plan. • The guiding document for federal research on climate and related environmental issues for the next decade. • Responds to Administration’s request to provide the best possible scientific information to support public discussion and decision-making on climate-related issues. • Describes the overall strategy for developing knowledge of climate and related environmental and human systems, and for encouraging application of this knowledge.

4. CCSP Goals CCSP Goals Overarching question: How will variability and potential change in climate and related systems affect climate and related systems and our way of life? CCSP Goals related to MCSS: • Improve knowledge of the Earth’s past and present climate and environment … 4) Understand the sensitivity and adaptability of different natural and managed ecosystems and human systems to climate and related global changes. • 5) Explore the uses and identify the limits of evolving knowledge to manage risks and opportunities related to climate variability and change. Core Approach:Develop improved science-based resources for decision- making.

5. Research Elements Research Elements CCSP Research elements especially relevant to the MCSS: • Climate Variability and Change (chapter 4). • Global water cycle (chapter 5). • Land use/land cover change (chapter 6). • Ecosystems (chapter 8). • Human contributions and responses (chapter 9). • Decision support resources development (chapter 11). • Observing and monitoring the climate system (chapter 12).

6. Example of issues, one element A few examples From the Climate Variability and Change chapter, some MCSS-related issues: Potential for changes in extreme events at regional to local scales. Possibility of abrupt change. Development of approaches to inform decision-making. • CCSP High-priority synthesis products • State-of-knowledge of thresholds of changes that could lead to sudden changes in some ecosystems and climate-sensitive resources. • Relationship between observed ecosystem changes and climate change. • Use and limitations of observations, data, forecasts, and other projections for selected sectors and regions.

7. Consider focusing issues 2) Consider focusing issues • Example: The Western Drought • The western U.S. has been experiencing a severe, sustained, large-scale drought over the past several years. This drought has attracted: • Intense media attention, including from major national media outlets. • Raised grave management concerns. There is discussion of the possibility for the first-ever “call” on the Colorado River under the terms of the Colorado River Compact. • We know that a large majority of the water supply in the western U.S. is deposited in the form of snow at high elevations and later released in snow melt, but observations of this natural storage, and how it may be changing, are woefully inadequate. Dillon Reservoir, Colorado

8. Lake Powell is at 42% capacity • Lake levels have dropped ~ 120 feet • Reservoirs above Lake Powell are currently at 62% of capacity • Net flow of water for WY 2004 to date is 58% of average. Severe Hydrologic Shortages Lake Powell Water Level (ft) Glen Canyon Dam Filled1980

9. Potential Western water supply crises and conflicts by 2025 (USBR) US Bureau of Reclamation analysis of potential water supply crises and conflicts by the year 2025 based on a combination of technical and other factors, including population trends and potential endangered species needs for water. Note:There is an underlying assumption of a statistically stationary climate.

10. What are Observed Western Climate Trends?

11. Observed and modeled SW winter temperature trends Observed trends are consistent with trends obtained in climate models forced by observed GHG changes. However, models forced by observed SST over this period also show warming, so both anthropogenic and natural factors are likely contributing.

12. Western U.S. Streamflow Trends From Stewart, Cayan, and Dettinger (2004) There is a marked trend toward an earlier melt out and earlier peak flows throughout almost all of the West, consistent with a winter warming trend. Such warming increases evaporation, extends the growing season, and likely also increases the demand for water resources.

13. U.S. West climate trends projectionsfrom transient-forced runs (8 models, 18 runs)

14. Projected temperature and precipitation trends

15. What are some potential implications? What would a warmer future climate imply for the mountainous west and adjacent regions, e.g., for water resources, ecosystems, recreation? • A few possibilities: • Less efficient water storage and release. • Increased vegetative stress - species, ecosystem losses. • Longer growing season, increased evaporation, and increased demand for already scarce water resources. 1928 2000 Western fires, 2002 Retreat of South Cascade Glacier, Washington

16. Other suggestions 3) Make connections to other ongoing priorities, such as natural disaster reduction, observations. Examples: Drought, COOP modernization (both have NOAA, USDA attention). 4) Focus on key regional issues. 5) Consider multiple stressors. Above all, aim toward end products that improve decision support and demonstrate value to taxpayers.

17. The End The End