Global Climate Change Won’t Be Pretty

Stephen T. JacksonDepartment of Botany &

Program in EcologyUniversity of Wyoming

Climate is always changing, so get over it.

Opinion: Global Warming Fears Overblown GUEST OPINIONBy Richard S. LindzenApril 16, 2007 issue – …What most commentators—and many scientists—seem to miss is that the only thing we can say with certainly about climate is that it changes. The earth is always warming or cooling by as much as a few tenths of a degree a year; periods of constant average temperatures are rare. Looking back on the earth's climate history, it's apparent that there's no such thing as an optimal temperature—a climate at which everything is just right. The current alarm rests on the false assumption not only that we live in a perfect world, temperaturewise, but also that our warming forecasts for the year 2040 are somehow more reliable than the weatherman's forecast for next week…

Global Glacial-Interglacial Cycles During the Last 450,000 Years

S.T. Jackson & J.T. Overpeck. 2000. Paleobiology (Suppl.).

It’s true!!!! CLIMATE CHANGE HAPPENS.

S.T. Gray, S.T. Jackson, J.L. Betancourt, C.L. Fastie. 2004. Journal of Climate.

Annual Precipitation Variation in the BighornBasin in the Last 750 Years

Photo courtesy of Sherrill Goodrich, USFS

The Rest of the Story:

Climate change – especially rapid climate change –is bad news for ecosystems, and for societies

The Past

13th Century “Great Drought”

S.T. Gray, S.T. Jackson & J.L. Betancourt. 2004. Journal of the American Water Resources Association.

E.R. Cook, R. Seager, M.A. Cane & D.W. Stahle. 2007. North American drought: reconstructions, causes, and consequences. Earth-Science Reviews.

E.R. Cook, R. Seager, M.A. Cane & D.W. Stahle. 2007. North American drought: reconstructions, causes, and consequences. Earth-Science Reviews.

Sout

h R

hody

, MI

Elk

Lake

, MN

Ferr

is D

unes

, WY

Wes

tern

San

dhill

s, N

E

Wes

tern

Illin

ois,

IL

Kili

man

jaro

Gul

f of O

man

Peatland in Alberta,

Canada (Yu et al. 2003)

Wet

Dry

GLOBAL GIGADROUGHT 4200 YR B.P.

R.K. Booth, S.T. Jackson, S.L. Forman, J.E. Kutzbach 2004. Holocene.

Photo by Tom WhithamSept 15, 2004 - North of San Francisco Peaks, AZ

The Present

Photos by Tom Whitham & Alicyn Gitlin

Four Corners region: severe mortality in•Pinyon/juniper woodland (esp. pinyon)•Ponderosa pine forest•Aspen forest•Cottonwood gallery forest

Photo by Tom WhithamSept 15, 2004 - North of San Francisco Peaks, AZ

What comes next?

West slope of Tumamoc Hill, Tucson

Courtesy of Julio Betancourt, USGS

www.desertmuseum.org

A.L. Westerling H.G. Hidalgo, D.R. Cayan & T.W. Swetnam 2006. Science.

Large potential for “surprises”

Interactions between climate change and:WildfiresPests and diseasesInvasive speciesHuman land-use and other activities

Feedbacks from land surface to atmosphere

The Future

J.W. Williams, S.T. Jackson & J.E. Kutzbach. 2007. Proceedings of the National Academy of Sciences.

(doubling)(tripling)

J.W. Williams, S.T. Jackson & J.E. Kutzbach. 2007. Proceedings of the National Academy of Sciences.

Projected climate change relative to late 20th Century (A2 scenario)Winter precipitation Summer precipitation

Winter temperature Summer temperature

P.C.D. Milly, K.A. Dunne & A.V. Vecchia. 2005. Global pattern of trends in streamflow and water availability in a changing climate. Nature 438:347-350.

a. Estimated percent change in streamflow between mid-21st Century and 20th Century under CO2 doubling

b. Number of model runs (of 24 total) with positive or negative change

Bad news for western US:

Streamflow decrease of 5 to 20% by 2050

High agreement amongdifferent models

Climate change:

Adaptation?

OrPrevention?

Rapid climate change:

Sometimes inevitablePotentially devastatingFull of surprisesTough to adapt to

War:

Sometimes inevitablePotentially devastatingFull of surprisesTough to adapt to

Accept and adapt? (“Bring it on!”)

Or minimize likelihood?

Vincent van Gogh. Wheat Field Under Threatening Skies. 1890