Managing Our Planet April 10, 2013 1

Variations and Changes in Weather and Climate Extremes

Thomas R. Karl, L.H.D. Director, National Climatic Data Center Chair, U.S. Global Change Research Program April 2013

Managing Our Planet April 10, 2013 2

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Outline • Motivation

– Billion-dollar Disasters

• State of the Science – U.S. Climate Extremes Index – Heat and Cold Waves – Precipitation/flooding and drought – Snowstorms – Tornadoes

• Implications

Managing Our Planet April 10, 2013 3

NOAA’s National Climatic Data Center (NCDC): Where are we? Who are we? What do we do?

• 160 Federal Employees ̶ Alaska, Colorado, Hawaii,

Maryland, Missouri, New York, North Carolina, Texas, Utah, Wisconsin

• 153 NCDC Headquarter Contractors

• 6 Regional Climate Centers • 2 Cooperative Institutes

Protecting the Past… Revealing the Future

NCDC Headquarters

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The Nation Is Climate-Conscious… for Good Reason

U.S. Billion-Dollar Weather and Climate Disasters: 1980 – 2011 Drought and Heatwaves

Hurricanes and Tropical Storms

Winter Storms and Crop Freezes

Flooding Wildfires Severe Local Storms

NOAA’s National Climatic Data Center

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Current State of Scientific Knowledge

Series of four workshops/papers for BAMS

Monitoring and Understanding Changes in Extreme Storm Statistics: State of Knowledge. Kunkel, K.E. et al., 2012, BAMS.

Monitoring and Understanding Changes in Heat Waves, Cold Waves, Floods and Droughts in the United States: State of Knowledge. Peterson, T.C. et al., 2013, BAMS.

Monitoring and Understanding Changes in Extreme Winds, Waves, and Extratropical Storms along the Coasts: State of Knowledge. Vose, R.S. et al., in review BAMS.

CMIP5 Climate Model Analyses: Climate Extremes in the United States. Wuebbles, D., et al., in review BAMS

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U.S. Climate Extremes Index • Includes measures of:

– Wetness/drought – Extreme

precipitation – Dry/wet days,

extremes – Extreme

temperature – Hurricanes

• The 2012 U.S. Climate Extremes Index value of 39.47 is the 2nd-largest of the metric’s period of record (since 1910)

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What’s Driving the Increase Since the 1970s?

Extremes in Maximum

Temperature

All graphs based on annual data

Extremes in Minimum Temperature

Drought Severity

and Water

Surplus

Extremes in 1-Day Heavy Precipitation

NOAA U.S. Climate Extremes Index http://www.ncdc.noaa.gov/extremes/cei/

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Heat Waves and Cold Waves

Peterson, T. C. et al., 2013. Monitoring and Understanding Changes in Heat Waves, Cold Waves, Floods and Drought in the United States: State of Knowledge. BAMS.

Standardized 4-day heat/cold wave index by decade.

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1-Day Heavy Precipitation Events Percent of the U.S. with much above normal 1-day heavy precipitation (>50.8mm)

Annual (Jan-Dec) 1910-2011

• A statistically significant increase in extremes NOAA U.S. Climate Extremes Index http://www.ncdc.noaa.gov/extremes/cei/

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Flooding and Precipitation

Regional similarities between trends of annual precipitation, droughts, and extremes of river flooding

River-Flow Trends in Annual Maximum: 85-127 years ending 2008

Trends in Total Annual Precipitation: 1909-2008

Peterson, T. C. et al., 2013.

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Drought

• Widespread persistent drought – 1930s (Central and Northern Great Plains, Northwest, Great Lakes) – 1950s (Southern Plains, Southwest), 1980s (West, Southeast) – First decade of the 21st century (West, Southeast)

Trends (% per century) • 1900 to 2011: -0.1% • 1930 to 2011: -10.0% • 1971 to 2011: +31.6%

Peterson, T. C. et al., 2013.

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Extreme Snowstorms

• Would changes in temperature and precipitation favor more or fewer extreme snowstorms?

• For the top 50 snowstorms during unusually warm, cool, dry and wet seasons, it varies: – E.g. Southern Plains much

snowier when cool – Northern Plains much

snowier when wet NOAA’s National Climatic Data Center

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Tornadoes & Convective Storms • Although some

ingredients that are favorable for severe thunderstorms have increased over the years, others have not

• Overall, changes in the frequency of environments favorable for severe convective storms have not been statistically significant

Kunkel, K.E., et al., 2012. BAMS.

Squires, M.F. et al., unpublished work

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Summary

• Widely varying suitability of our data and physical understanding of various extreme events

• Positive correlation between detection and understanding

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Questions?

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