NOAA Climate Communications WorkshopMay 6, 2013 1 What can we say about our changing climate and...

NOAA Climate Communications WorkshopMay 6, 2013 1

What can we say about our changing climate and trends in

extreme events?

Wayne Higgins, Ph.D.Acting Director,NOAA National Weather ServiceNational Centers for Environmental PredictionMay 2013


OutlinePart 1: The Demand for Useable Information on Extremes

Part 2: Observed & Projected Trends in Extremes

Key Issues: Temperature Precipitation Coastal Vulnerability

Part 3: Take Away Messages


The Demand for Useable Information on Extremes

PART ONE


Extremes matter• Changes in weather and climate extremes

have profound impacts and consequences.

Rising Demand for Information • Compelling scientific evidence shows that

the nature of extreme events is altered by climate variations and change.

• Decision makers are demanding improved information on how changes in climate may influence future extremes.

• Also want to know about potential impacts a changing climate and extremes may have on our lives, livelihoods, businesses and the ecological systems that support us.

DisastersDisasters

Snowstorms/Blizzards

Snowstorms/Blizzards

TornadoesTornadoes WildfiresWildfires

Hurricanes & Tropical Storms

Hurricanes & Tropical Storms

FloodsFloods

GeophysicalGeophysical

Heat wavesHeat waves

DroughtsDroughts

Source: NOAA Climate Adaptation Portfolio

Weather & Climate Extremes


Heat-Trapping Greenhouse Gases are Increasing

• Pre industrial levels: ~280 ppm; Current levels: ~396 ppm; Current rate of increase: ~1.9 ppm/yr • Concentrations today far exceed the natural range over the last 650,000 years

Source: http://www.epa.gov/climatechange/science/indicators/ghg/ghg-concentrations.html


Global Temperatures are Increasing

•Global surface temperatures have increased about 1.5°F ( 0.8°C) since ~1900.

• Average U.S. surface temp. has risen +0.13°F per decade since 1901 and has increased to +0.31-0.45°F per decade since the late 1970s.

•The warming has not been uniform. Some areas have cooled slightly.

•The recent warmth has been greatest over North America and Eurasia. Source: National Climatic Data Center


The Earth is Warming

Source: National Climatic Data Center


Natural Disasters are on the Rise

Source: http://www.munichreamerica.com/webinars/2013_01_natcatreview/MunichRe_III_NatCat01032013.pdf


The Nation Is Weather/Climate Conscious… for Good Reason

Drought and Heat Waves

Hurricanes and Tropical Storms

Winter Storms and Crop Freezes

Flooding Wildfires Severe Local Storms

Source: National Climatic Data Center

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


PART TWO

Observed & Projected Trends in Extremes


Key Issue: Temperature

• Changes in trends of maximum and minimum temperatures

• Changes in “normal” distribution of temperatures


Observed:Increasing Temperatures

Statewide changes in annual “normal” temperatures (1981-2010 compared to 1971-2000)

Source: http://www.ncdc.noaa.gov/oa/climate/normals/usnormals.html

Maximum Minimum


Observed:Temperature Extremes

•More unusually warm days and nights in recent decades

•Fewer unusually cold days and nights

•Increasing number of heat waves, but 1930s still most severe

http://www.climatescience.gov/Library/sap/sap3-3/final-report/sap3-3-final-ExecutiveSummary.pdf


Projected:Temperature Extremes

• Warm days and nights, and heat waves - very likely more frequent.

• Cold days and cold nights – very likely much less frequent.

• Days with frost – very likely to decrease.

http://www.climatescience.gov/Library/sap/sap3-3/final-report/sap3-3-final-ExecutiveSummary.pdf


Key Issue: Precipitation

• Changes in precipitation

patterns and intensity• Changes in drought

frequency, intensity, and

duration• Changes in snowpack• Changes in precipitation

type (e.g., rain vs. snow)


Observed: Precipitation Extremes

Percent of the U.S. with much above normal 1-day heavy precipitation (>2 inches)

• A statistically significant increase in extremes since the late 1970s

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

Annual (Jan-Dec) 1910-2011


Observed:Precipitation Extremes

Source: http://www.globalchange.gov/publications/reports/scientific-assessments/us-impacts

Percent increases in the amount of precipitation falling in very heavy events (defined as the heaviest 1% of all daily events) from 1958 to 2011.

There are clear trends toward a greater amount of very heavy precipitation for the nation as a whole, and particularly in the Northeast and Midwest.


Projected:Precipitation Extremes

Source: http://www.globalchange.gov/publications/reports/scientific-assessments/us-impacts

•Lightest precipitation is projected to decrease.

• Heaviest precipitation is projected to increase strongly.

• Higher greenhouse gas emission scenarios produce larger changes in extreme precipitation.


Key Issue: Coastal Vulnerability

• Sea-level change• Increasing Storm Intensity• Storm Surge & Flooding


Observed:Sea Level Rise

Source: http://epa.gov/climatechange/science/indicators/Based on NOAA Sea Level Trends data

• Tide gauges confirm that global sea level has risen ~0.07 inches per year since 1880 (i.e., ~ 8 inches )

• Since 1993, satellites confirm that sea level has risen roughly twice as fast as the rate over the last century


Projected:Sea Level Rise

• Projecting future rates

of SLR is challenging• Model projections

suggest ~ 1– 4 ft is plausible by 2100

• Where risk tolerance is low, some decision makers may wish to use ~8 in to 6.6 ft by 2100

• Scientists continue to work to improve models


Observed:Hurricanes in the Atlantic Basin

• No clear trend in numbers of

hurricanes since 1878• Changes in observation methods

make it difficult to identify long-term trends

• Hurricane strength has increased since 1980s

• Six of the 10 most active years have occurred since the mid-1990’s


Projected:Hurricanes in the Atlantic Basin

• The intensity of the strongest hurricanes is projected to continue to increase as the oceans continue to warm

• Other storm trends --e.g. numbers of hurricanes, tornadoes, hail, thunderstorms, etc. -- are uncertain and being studied

Source: http://www.gfdl.noaa.gov/global-warming-and-hurricanes.


Current State of Scientific Knowledge

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

• Positive correlation between detection and understanding


Demand for Climate Information is Increasing Across Space and Time Scales

NOAA and other agencies are working to provide a suite of products from near term forecasts to long term projections, tailored to stakeholders’ needs.


Take Away Messages

PART THREE


Take Away Messages

• Observed and Projected trends– Heavy downpours are increasing in most regions of the U.S.; the largest have

been in the Midwest, southern Great Plains, and Northeast.– Heat waves have been most prevalent in the West; droughts in the Southwest

and heat waves everywhere projected to become more intense– Global sea level rise projected to rise another 8” to 6.6 ft. by 2100, with local

variations.– Stronger hurricanes in the North Atlantic expected as the ocean warms

• Projecting local scale impacts are difficult – Regional scales of projections frustrate local decision makers.

• NOAA & partners are working to improve delivery of useful information to support a variety of decisions– Links between trends in green-house gas concentrations and some types of

extremes, including hurricanes, tornadoes, and snowstorms have not been fully established, but remain active areas of research.

– Credible extrapolation of trends (other than for gross features of the climate) depends on improved understanding and future model improvements.


Questions?Questions?

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