Thomas R. Karl

Director, National Climatic Data CenterChair, Subcommittee on Global Change Research

Billion-Dollar Disasters and Changes in Extremes of

Weather & ClimateIGES Executive Roundtable on ClimateApril 25, 2012

IGES Executive Roundtable on ClimateApril 25, 2012 2

©W

arre

n F

aild

ey -

Wea

ther

stoc

k.co

mr

Outline• Billion-dollar Disasters• Changes in Extremes

– Heat and Cold Waves– Precipitation/flooding and drought– Snowstorms– Tornadoes

• Summary

IGES Executive Roundtable on ClimateApril 25, 2012

Billion-Dollar Weather and Climate Disasters 2011

3

Three more in 2011 approaching $1B1. Late-October Northeast winter storm2. April 19-20 Midwest and Southeast tornadoes3. August 18-21 Midwest and East high wind & hail

NOAA/NCDC

IGES Executive Roundtable on ClimateApril 25, 2012

Billion-Dollar Weather and Climate Disasters• Since 1980, 114 billion-dollar weather and climate disasters in U.S.• Total losses since 1980 of billion-dollar disasters exceed $800 billion.• Is the U.S. becoming more exposed and/or sensitive to severe events?

A Record 14 Disasters in the U.S. in 2011Three more approaching $1B

4

NOAA Billion-Dollar Disasters http://www.ncdc.noaa.gov/oa/reports/billionz.html

Status of Present Knowledge

Monitoring and Understanding Changes in Extreme Storm Statistics: State of Knowledge - Kunkel, K.E. et al. (23 others). Tentatively accepted (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. (27 others). In Review (BAMS).

Monitoring and Understanding Changes in Extreme Winds, Waves, and Extratropical Storms along the Coasts: State of Knowledge - Vose, R.S. et al. (25 others) To be submitted (BAMS).

IGES Executive Roundtable on ClimateApril 25, 2012

U.S. Annual Maximum & Minimum Temperatures

6Katz, R. W., Unpublished results, 2012.

Percent of the U.S. much above normal Percent of the U.S. much below normal

Not statistically significant

Maximum Temperatures

Minimum Temperatures

IGES Executive Roundtable on ClimateApril 25, 2012 7

“Normalized” Temperature DistributionNorthern Hemisphere Land - Jun-Jul-Aug (1951-1980 Base Period)

Hansen, J. et al., 2012 (submitted). Public Perception of Climate Change and the New Climate Dice. Proceedings of the National Academy of Science.

“Normalized” Departures

IGES Executive Roundtable on ClimateApril 25, 2012

1-Day Heavy Precipitation Events

8

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 Indexhttp://www.ncdc.noaa.gov/extremes/cei/

IGES Executive Roundtable on ClimateApril 25, 2012

Extreme Precipitation

9

Differences between two periods (1990-2009 minus 1971-1989) for daily, 1-in-5yr extreme events and coincident (spatial and temporal) precipitable water values

Extreme Precipitation Frequency Index Difference

(Percent)

Precipitable Water Difference(Percent)

Adapted from Kunkel, K.E. et al., 2012 (In Review). Monitoring and Understanding Changes in Extreme Storm Statistics: State of Knowledge. BAMS.

All changes positive All changes positive

Flooding and Precipitation

Regional similarities between trends of annual precipitation, droughts, and extremes of river flooding Regional similarities between extremes of river flooding and extremes of precipitation is not

as congruent

River-Flow Trends in Annual Maximum

Trends in Total Annual Precipitation: 1909-2008

Difference in Number of Months with Moderate to Extreme Drought

85-127 years ending 2008

85-127 years ending 2008

Peterson, T. C. et al., 2012 (In Review). Monitoring and Understanding Changes in Heat Waves, Cold Waves, Floods and Drought in the United States: State of Knowledge. BAMS.

IGES Executive Roundtable on ClimateApril 25, 2012 11

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., 2012 (In Review). Ibid.

IGES Executive Roundtable on ClimateApril 25, 2012

Projected Change (A2 Scenarios – “Higher Emissions”) in North American Precipitation (Late 21st Century)

12

15 Climate Models

Global Climate Change Impacts in the United States, Thomas R. Karl, Jerry M. Melillo, and Thomas C. Peterson, (eds.). Cambridge University Press, 2009.

IGES Executive Roundtable on ClimateApril 25, 2012

Combined Drought Severity and Water Surplus

13

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

IGES Executive Roundtable on ClimateApril 25, 2012

Extreme Snowstorms

14

Number of extreme snowstorms occurring each decade within the six U.S. climate regions in the eastern two-thirds of the contiguous U.S.

Most severe storms for each of the six climate regions from 1900 to 2010

Temperature Anomalies During Season of Extreme Events

Precipitation Anomalies During Season of Extreme Events

-1%

-9% 19%

5%-6%

8%

• Every region had two of the five storms of record occurring during seasons with above average temperatures

Fre

qu

enc

y

Kunkel, K.E., et al., 2012 (Tentatively Accepted). BAMS.

IGES Executive Roundtable on ClimateApril 25, 2012 15

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

U.S. Annual Tornadoes

Kunkel, K.E., et al., 2012 (In Review). BAMS.

IGES Executive Roundtable on ClimateApril 25, 2012 16

Tornadoes & Convective Storms

• For continental U.S. severe tornadoes (L≥10 km), (top) total path length per year, and (bottom) the number per year

r² = 0.1269

r² = 0.27

Malamud, B. D. and D. L. Turcotte, 2012. Statistics of severe tornadoes and severe tornado outbreaks. Atmos. Chem. Phys. Discuss.

Len

gth

per

yea

r (k

m/y

r)

Nu

mb

er per year

IGES Executive Roundtable on ClimateApril 25, 2012 17

Tornadoes & Convective StormsWind Shear vs. Vertical Velocity–6km proximity values

Each cell is best viewed as a conditional probabilityKunkel, K.E., et al., 2012 (In Review). BAMS.

IGES Executive Roundtable on ClimateApril 25, 2012 18

Summary• Widely varying suitability

of our data and physical understanding of various extreme events

Adapted from Lubchenco, J., and T. Karl, 2012. Predicting and managing extreme weather events. Physics Today.

Questions?

19