Impact of Climate Change on Peri-Glacial Environments

Arctic(a) vs. Antarctica land: 8 X 106 km2 (30% ice) \ substantial terrestrial food \ land mammals \ herbivorous & insectivorous birds (high diversity) land: 14 X 106 km2 (97% ice) \ no terrestrial food \ no land mammals \ no herbivorous or insectivorous birds (low diversity)

“tundra” = treeless barrens Tundra ecosystems “tundra” = treeless barrens

Global distribution of tundra

Arctic ecosystems in Canada N.Arctic = polar desert S.Arctic = tundra

Tundra ecosystems Tundra ecosystems are associated with areas of extreme near-polar climate which operates either directly, or through a series of environmental forcings (primarily thaw-layer dynamics) to limit productivity and biodiversity.

Tundra climate stations Barrow Treeline Tiksi Churchill 75°N 60°N Svalbard Iqaluit Gulf Stream

Frost-free days Treeline

Mean annual snowfall (mm) Treeline

Permafrost distribution

Alaska Siberia

Boreal forest Tundra mean location Polar Front tree growth Jan July 120 30 mean #d >10°C 150 60 frost-free days pollen/seed viability 150 240 mean #d <0°C Boreal forest Tundra patchy discontinuous continuous Permafrost

Animal life

Climate change

Hockey Stick - Earth’s Temperature Variations: Past 1000 Years The hockey stick has been the brainchild of Prof. Mann of the University of Virginia. It appeared in the IPCC2001 report but it has been highly controversial since some claim that it does not take into account the warm climate half a millennia ago. Prof Mann says it shows up in the gray area and Europe may be a special case.

Source: Arctic Climate Impact Assessment website

Associated Climate Changes Global sea-level has increased 1-2 mm/yr; in 80 years a rise in sea level between 3.5 and 34.6 in. (up to 3ft) is expected Duration of ice cover of rivers and lakes decreased by 2 weeks in N. Hemisphere Arctic ice has thinned substantially, decreased in extent by 10-15%

Source: Intergovernmental Panel on Climate Change, 2001 Report Reduced permafrost in polar, sub-polar, mountainous regions Growing season lengthened by 1-4 days in N. Hemisphere Retreat of continental glaciers on all continents Snow cover decreased by 10% (reduced solar reflection) Source: Intergovernmental Panel on Climate Change, 2001 Report

Since 1979, the size of the summer polar ice cap has shrunk more than 20 percent. (Illustration from NASA) (http://www.nrdc.org/globalWarming/qthinice.asp)

Recent (post-1950) climate change in polar regions Arctic: Reduction in sea ice extent and thickness Northward treeline shifts (e.g. E. coast Hudson Bay) Increased lakes, bogs (e.g. Ellesmere Island) Range expansions (e.g. dragonflies - Inuvik - 2000) Antarctic: Ice shelf disintegration (e.g. N. Larsen & Wordie Shelf) Spread of flowering plants (e.g. Antarctic hairgrass has expanded its range 25-fold since 1964) New lichen species colonizing recently deglaciated areas

Polar Amplification- Feedbacks Ice-Albedo Feedback –relevant to retreating perennial ice cover and also over land Cloud feedback – positive or negative, depending on the height of clouds Other feedbacks are mainly positive

Total Ice Cover/Monthly Anomalies From 1978 to 1996, the trend in the ice extent was -2.2% per decade. Since 1996, the trend has changed to -10.1% per decade suggesting a large acceleration in the decline. Acceleration in the decline makes it difficult for ice to recover because of ice albedo feedback. -10.1%/dec The total ice cover has been a lot less variable, Overall the decline is 3.6 % per decade but in the first thirteen years of satellite data the deline was only about 2% per decade. From 1996, the slope shifted and the decline is now 11% per decade, and comparable with perennial ice data. -10.7%/dec

Permafrost in Alaska Not much has been done in terms of satellite analysis over permafrost regions. The reason is because sensor radiations do not penetrate through the surface to get subsurface information. We hope to change than through a combination of models and data.