Introduction

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Climate Future: Science and PolicyClimate Future: Science and Policy

Randall M. DoleRandall M. DoleNOAA-CIRES Climate Diagnostics CenterNOAA-CIRES Climate Diagnostics Center

Mountain Climate Sciences SymposiumMountain Climate Sciences SymposiumLake Tahoe, CALake Tahoe, CA

May 25, 2004May 25, 2004

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How might this accomplished in the present budget environment?

Key Symposium Goal

Develop support for long-term, interdisciplinary, Develop support for long-term, interdisciplinary, integrated climate and climate-related research integrated climate and climate-related research and monitoring in the western mountains.and monitoring in the western mountains.

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1) Make explicit connections to goals in the Climate 1) Make explicit connections to goals in the Climate Change Science Program (CCSP) strategic plan.Change Science Program (CCSP) strategic plan.

Strategies for Success

•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.

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Overarching question: How will variability and potential change Overarching question: How will variability and potential change in climate and related systems affect climate and related in climate and related systems affect climate and related systems and our way of life?systems and our way of life?

CCSP Goals related to MCSS:CCSP Goals related to MCSS:

CCSP Goals

1)1) Improve knowledge of the Earth’s past and present climate and Improve knowledge of the Earth’s past and present climate and environment …environment …

4)4) Understand the sensitivity and adaptability of different natural and Understand the sensitivity and adaptability of different natural and managed ecosystems and human systems to climate and related managed ecosystems and human systems to climate and related global changes.global changes.

5)5) Explore the uses and identify the limits of evolving knowledge to Explore the uses and identify the limits of evolving knowledge to manage risks and opportunities related to climate variability and manage risks and opportunities related to climate variability and change.change.

Core Approach:Core Approach: Develop improved science-based resources for decision-Develop improved science-based resources for decision-making.making.

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CCSP Research elements especially relevant to the MCSS:CCSP Research elements especially relevant to the MCSS:

Research Elements

• 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).

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From the Climate Variability and Change chapter, some MCSS-From the Climate Variability and Change chapter, some MCSS-related issues:related issues:

A few examples

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.

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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

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Severe Hydrologic Shortages

3400

3450

3500

3550

3600

3650

3700

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Lake Powell Water Level (ft)

Filled1980

• 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.

Glen Canyon Dam

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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.

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What are Observed Western Climate Trends?

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Observed and modeled SW winter temperature trendsObserved and modeled SW winter temperature trends

Observed trends are consistent with trends obtained in climatemodels 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.

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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.

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

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Projected temperature and precipitation trends

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What would a warmer future climate imply for the mountainous west and adjacent regions, e.g., for water resources, ecosystems, recreation?

What are some potential implications?

A few possibilities:A few possibilities:

• Less efficient water storage and release.Less efficient water storage and release.

• Increased vegetative stress - species, ecosystem losses.Increased vegetative stress - species, ecosystem losses.

• Longer growing season, increased evaporation, and increased demand Longer growing season, increased evaporation, and increased demand for already scarce water resources.for already scarce water resources.

Western fires, 2002Western fires, 200219281928 20002000

Retreat of South Cascade Glacier, WashingtonRetreat of South Cascade Glacier, Washington

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3) 3) Make connections to other ongoing prioritiesMake connections to other ongoing priorities, such as , such as natural disaster reduction, observations. Examples: natural disaster reduction, observations. Examples: Drought, COOP modernization (both have NOAA, USDA Drought, COOP modernization (both have NOAA, USDA attention).attention).

4) 4) Focus on key regional issues.Focus on key regional issues.

5) 5) Consider multiple stressors.Consider multiple stressors.

Above all, aim toward end products that improve Above all, aim toward end products that improve decision support and demonstrate value to taxpayers.decision support and demonstrate value to taxpayers.

Other suggestions

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The EndThe End