Global Outlook for Ice & Snow

21 000 10 000

P l e i s t o c e n e

H o l o c e n e

Late Glacial

Years before present 400 000 300 000 200 000 100 000

Year 1500 1600 1700 1800 1900 2007

Atmospheric carbon dioxide (CO 2 ) concentrations (ppm)

320

Ice core analysis

280

Observations

240

200

Ice core analysis

4

0.5

Reference period: 1950

Reference period: 1961-1990

Temperature variations (°C)

0.25

0

Observations

0

-4

-0.25

-8

Multiple proxy reconstructions

Ice core analysis

-0.5

400 000 Years before present

300 000 200 000 100 000

1500 Year

1600 1700 1800 1900 2007

Last Glacial Maximum 21 000 years ago

Repeated glaciations, ice ages, inter- rupted by warmer interglacial periods

Little Ice Age

Sources: Barnola, J.-M., Raynaud, D., Lorius, C. and Barkov, N.I. (2003). Historical CO 2 record from the Vostok ice core. In Trends: A Compendium of Data on Global Change . Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge CRU (2007). CRUTEM3v dataset . Climate Research Unit, University of East An- glia. http://www.cru.uea.ac.uk/cru/data/temperature [Accessed 5 May 2007] Etheridge, D.M., Steele, L.P., Langenfelds, R.L., Francey, R.J., Barnola, J.-M. and Morgan, V.I. (1998). Historical CO 2 records from the Law Dome DE08, DE08-2, and DSS ice cores. In Trends: A Compendium of Data on

Global Change . Carbon Dioxide Information Analysis Center, Oak Ridge Na- tional Laboratory, U.S. Department of Energy, Oak Ridge Keeling, C.D. and Whorf, T.P. (2005). Atmospheric CO 2 records from sites in the SIO air sampling network. In Trends: A Compendium of Data on Global Change . Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge Mann, M.E. and Jones, P.D. (2003). 2,000 Year Hemispheric Multi-proxy Temperature Reconstructions, IGBP PAGES/World Data Center for Paleo- climatology Data Contribution Series #2003-051 . NOAA/NGDC Paleoclima- tology Program, Boulder