Transcript Slide 1

Modern Climate Change:
Where have we been and where
are we headed?
Thomas R. Karl, L.H.D.
Director, National Climatic Data Center
Chair, U.S. Global Change Research Program
April 2013
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Outline
• Motivation
– Billion-dollar Disasters
– U.S. Climate Extremes Index
• Past and Future Climate
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©Warren Faildey -Weatherstock.comr
– Temperature
– Heat and Cold Waves
– Precipitation/flooding and drought
– Snowstorms
– Tornadoes
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NOAA’s National Climatic Data Center (NCDC):
Where are we? Who are we? What do we do?
Protecting the Past… Revealing
the Future
• 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
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
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NOAA’s National Climatic Data Center
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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 2ndlargest of the metric’s
period of record
(since 1910)
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Current State of Scientific Knowledge
Series of four workshops/papers for BAMS
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
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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What’s Driving the Increase
Since the 1970s?
Extremes in
Maximum
Temperature
Extremes in
Minimum
Temperature
Drought
Severity
and
Water
Surplus
Extremes in
1-Day Heavy
Precipitation
All graphs are based on annual data
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NOAA U.S. Climate
Extremes Index
http://www.ncdc.noa
a.gov/extremes/cei/
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“Loaded Climate Dice”
• 2001-2011 compared to 1951-80
– Doubled likelihood of a hot month (red shading) compared to 1951-80 (a)
– Almost 10% chance of what used to be a 1 in 1000 year event (1951-80) (b)
All Stations (Northern Hemisphere Land – Summer)
a
b
Limited Stations (Northern Hemisphere Land – Summer)
Based on Hansen, J. et al., 2012
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Standardized monthly temperature anomalies
U.S. Spring and Summer
• Maximum temps
Maximum Temps
– Highly significant trend at
national scale
– Weak trend in drought
regions
– 2012 spring/summer was
about a one in 1600-year
event in a stationary climate
• Minimum Temps
Minimum Temps
– Highly significant trend at
national scale and drought
regions
– 2012 spring/summer was
about a one in 450-year
event in a stationary climate
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KarlSustainable
et al., EOSCampuses
2012
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Heat Wave Index for the U.S.
• Shows the number of 4-day intervals exceeding a threshold for a 1 in 5-yr
recurrence.
Updated from Kunkel et al. 1999 BAMS
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Heat Waves and Cold Waves
Standardized 4-day heat/cold wave index by decade.
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.
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Change in number of very hot days
• All regions are projected to
have an increase in the
number of very hot days
• The hottest climates are
projected to add over a
month (30+ days) of days
over 90
• Hot days have impacts on
human health, air quality,
energy use, and agriculture.
• Model studies indicate that
intense heat waves that now
occur once every 20 years
are projected to occur about
every other year in much of
the country by the end of
this century (Karl et al.,
2009)
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Change in number of very cold days
• All regions projected to
be less cold
• Some regions projected
to lose 20+ days per
year below freezing
• Impacts on freezing of
lakes, human health,
energy use, agriculture
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Intensified Water Cycle
Adapted from National Climate Assessment unpublished work
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1-Day Heavy Precipitation Events
Percent of the U.S. with much above normal 1-day heavy precipitation
Annual (Jan-Dec) 1910-2012
•
A statistically significant increase in extremes
NOAA U.S. Climate Extremes Index http://www.ncdc.noaa.gov/extremes/cei/
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Precipitable Water Difference
(Percent)
Difference between 1990-2009 minus 1971-1989 for daily, 1-in-5-year extreme events
Peterson, T. C. et al., 2013.
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Changes in Heavy Precipitation
• The total amount of
precipitation falling
on days that exceed
the 99th percentile
threshold of daily
precipitation
amounts during the
30-yr period of
1983-2012 with
respect to the prior
30-yr period of
1953-1982. The
differences are
expressed as
percent of the
1953-1982 values.
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Maximum Daily Precipitation
• Most places projected to have higher maximum daily precipitation
Kunkel et al. 2013 GRL
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Extreme Precipitation:
Projected Future Trends
• Potential Maximum Precipitation
likely to increase with increases in
atmospheric water vapor due to
warming oceans and increased
evaporation
Potential Maximum
Precipitation
Change in Precipitation Intensity
Adjusted for
future water
vapor trends
Adjusted for
recent water
vapor trends
Currently
used in PMP
NOAA/NCDC
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Trends in Flooding and Precipitation
River-Flow Trends in Annual Maximum:
85-127 years ending 2008
Trends in Total Annual Precipitation:
1909-2008
Regional similarities between trends of annual precipitation,
droughts, and extremes of river flooding
Peterson, T. C. et al., 2013.
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U.S. Drought of 2012
Illinois
From MODIS data.
Courtesy of I. Becker-Reshef, E. Vermote, M. Claverie and C. Justice,
University of Maryland.
Karl et al, 2012 EOS
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Drought
Trends (% per century)
•
•
•
1900 to 2011: -0.1%
1930 to 2011: -10.0%
1971 to 2011: +31.6%
• 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)
Peterson, T. C. et al., 2013.
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Projected Change (A2 Scenarios – “Higher Emissions”)
in North American Precipitation (Late 21st Century)
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.
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Projected Change in
Standardized Precipitation Index
•
Simulated difference (%) in the number of months with a Standardized
Precipitation Index (SPI) value of less than -1, for the 2041-2070 time period with
respect to the reference period of 1971-2000 for a high (SRES A2) emissions
scenario.
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Historical
Drought
• The percent area of the
western half of the United
States experiencing mild to
extreme drought (Palmer
Drought Severity Index ≤ -1.0)
from 800-2000 (graph at top),
reconstructed from tree ring
data, smoothed with a 60-year
spline (heavy line) and a 20year (light line).
• Droughts earlier in the
paleoclimatic record (some
600-1200 years ago) were
much more severe and
extensive than droughts of the
20th century.
Peterson 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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