Extreme Weather in a Warming World

Extreme Weather in a Warming WorldDavid H. Bromwich & Aaron B. Wilson

Byrd Polar & Climate Research CenterAtmospheric Sciences Program, Department of Geography

The Ohio State University

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• Weather & Climate• Global Warming Overview• Climate Change Projections (IPCC AR5)

• CO2,Air Temperature, Global Sea-level Rise, Sea Ice, and Hurricanes

• Climate Change Impacts in the U.S.• Temperature and Precipitation Extremes

OUTLINE

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Current state of the atmosphere

Caused by physical imbalances of heat, atmospheric pressure, and moisture

Consists of the short-term (minutes to days) variations in the atmosphere.

WEATHER

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Slow-varying aspects of the atmosphere–hydrosphere–land surface system

Suitable averages over periods of a month or more.

Variability including extremes.

CLIMATE

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ANNUAL GLOBAL LAND AND OCEAN TEMPERATURE ANOMALIES

2015 (YTD): 1.53°F

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But wait, I remember...

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“It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century.”

“Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system.”

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It’s a CO2 Problem

Atmosphere

Seawater

pH

14Credit: NOAA

Representative Concentration Pathways

RCP 2.6 assumes rapid reductions in emissions – more than 70% cuts from current levels by 2050

RCP 8.5 assumes continued increases in emissions (“business-as-usual”)

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Air Temperature

“Global surface temperature change for the end of the 21st century is projected to be likely to exceed 1.5°C relative to 1850 to 1900 in all but the

lowest scenario considered, and likely to exceed 2°C for the two high scenarios.” –IPCC 2013

PROJECTED

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Can the future climate support life?

1976–2005 historical CO2

25 km Regional Climate Model forced by 3 IPCC Global Climate ModelsTmax = Annual Average Daytime High Temperature

140°F

CO2 Equivalent > 550 ppm CO2 Equivalent > 1200 ppm

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Sea-Level Rise

http://sealevel.colorado.edu/

OBSERVED PROJECTED

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19Credit: NOAA

- Article by Erik Mack

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Arctic Sea IceOBSERVED PROJECTED

“A nearly ice-free Arctic Ocean in September before mid-century is likely for the RCP8.5 (medium confidence). – IPCC 2013

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Hurricane Intensity

PDI is an aggregate of storm intensity, frequency, and duration and provides a measure of total hurricane power

over a hurricane season.

International Best Track Archive for Climate Stewardship (IBTrACS)

UW/NCDC is the University of Wisconsin/NOAA National Climatic Data Center satellite-derived hurricane intensity dataset, and ADT-HURSAT is the Advanced Dvorak Technique–Hurricane Satellite dataset (Satellite-based reanalyses)

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Projected Hurricane Genesis Potential Index: NHCombines the values of shear,

mid-tropospheric relative humidity, measure of the thermodynamic

limit on storm intensity (MPIv), and large-scale vorticity to estimate the

potential for a storm to develop. Larger values of GPI are

associated with enhanced tropical storm development.

Increase in June-November GPI across NH tropics

Atlantic and E. Pacific generally smaller changes

W. and C. Pacific exhibit substantial increases

N. Indian Ocean shows a moderate increase in GPI.

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“A new report released by the University of Cambridge argues that the risks of climate change should be assessed in the same way as risks to national security, financial stability, or public health, concentrating on the worst that can happen and how likely that may be.” – US Water Alliance

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Observed U.S. Temperature Change

The colors on the map show temperature changes over the past 22 years (1991-2012) compared to the 1901-1960 average, and compared to the 1951-1980 average for Alaska and Hawai‘i.

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Projected U.S. Temperature Change

Projections show change in average temperature in the later part of this century (2071-2099) relative to the late part of last century (1970-1999). (Figure source: NOAA NCDC / CICS-NC).

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Observed U.S. Precipitation Change

The colors on the map show annual total precipitation changes for 1991-2012 compared to the 1901-1960 average.

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Projected U.S. Precipitation Change

Seasonal precipitation change for 2071-2099 (compared to 1970-1999) as projected by recent simulations. Hatched areas indicate that the projected changes are significant and consistent among models. White areas indicate that the changes are not projected to be larger than could be expected from natural variability. (Figure source: NOAA NCDC / CICS-NC).

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Observed U.S. Heavy Precipitation Change

The map shows percent increases in the amountof precipitation falling in very heavy events (defined as theheaviest 1% of all daily events) from 1958 to 2012 for each region of the continental United States.

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Projected U.S. Heavy Precipitation Change

Maps show the increase in frequency of extreme daily precipitation events (a daily amount that now occurs once in 20 years) by the later part of this century (2081-2100) compared to the later part of last century (1981-2000).

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SYNTHESIS• Climate is what we expect. Weather is what we get.

• By mid-21st century – major climate change is virtually certain

• By the end of the 21st century – models suggest we can avoid extraordinary climate change

• The most dramatic impacts of climate change on the US will be extreme temperature and intense precipitation events

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David H. Bromwichbromwich.1@osu.edu

@ByrdPolar

/ByrdPolar

/ByrdPolarhttp://polarmet.osu.edu

This presentation was a part of The Risk Institute’s Executive Education Series on November 12, 2015. For more information visit fisher.osu.edu/risk.