E-mail A Friend Tell a friend about the information found on this page by sending them an e-mail.   Your Name: Your E-mail:   Type an e-mail address, then click add: Add a Personal Message: (Optional)

May/June 2002 issue	In this issue Table of Contents Editor’s Notebook Inside Story Feature: Grasshoppers À la carte Mosaic Reverberations

Future Extremes
Predicting Canada’s climate in 2050
By Steven Fick

As Canada debates its pledge to ratify the Kyoto Protocol, which commits signatory nations to reduce their greenhouse-gas emissions, opponents claim that climate models are too uncertain to underpin our energy policies. What, then, do we know, and what can we reasonably speculate?

We know with certainty that greenhouse gases, such as carbon dioxide, warm the atmosphere and that the concentration of these gases is increasing. We are virtually certain that global temperatures have increased over the past century, especially over the past two to three decades, and that these increases are beginning to affect various natural systems. Glaciers, sea ice and permafrost, for example, have shrunk. Plants, animals and diseases have followed warmer temperatures into new areas.

Most scientists believe that human activity is contributing to these changes, but the natural variability of climate makes it difficult to prove this or to predict with confidence what the future holds. However, if greenhouse gases double by mid-century, as emissions studies suggest, dramatic changes are predicted for every region of Canada. Here are some projections, based on current climate models, of what we may expect a half-century from now.

THE NORTH • Dramatically higher winter temperatures • Disappearance of up to half of discontinuous permafrost • Inundation of coastal settlements from sea-level rise • Tundra shrinking by a third of its present extent • Sea ice thinning, allowing a longer, more extensive shipping season

BRITISH COLUMBIA AND THE YUKON • Flooding in coastal wetlands and communities • Glaciers retreating • More frequent summer droughts on the southern coast and interior • More winter precipitation • Earlier and higher spring floods • Disappearance of sockeye salmon from Canadian waters

PRAIRIES • More frequent and severe droughts in southern areas • Drier soils • Declines in summer stream flows • Longer growing seasons • Increased crop production in the north where suitable soils exist • Shrinking seasonal wetlands • Grasslands migrating northward

ONTARIO AND QUEBEC • More droughts and forest fires in Ontario • Increased precipitation in northern Quebec • Longer growing seasons • Increased crop production in the north where suitable soils exist • Lowered water levels, affecting shipping on the St. Lawrence River and Great Lakes • More days when heat and air pollution adversely affect public health

ATLANTIC • Rising sea levels causing floods, coastal erosion and sedimentation • Changes to distribution of fish and seabirds • Loss of fish habitat • Reduced sea ice, affecting marine transportation and offshore oil and gas industry

SOURCES:
Shifting climate zones: R. T. WATSON ET AL. (EDITORS), CLIMATE CHANGE 1995, INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE; R. B. BAILEY, ECOREGIONS OF THE CONTINENTS, U.S. FOREST SERVICE
Sockeye: D. WELCH/DEPARTMENT OF FISHERIES AND OCEANS
Wind erosion: S. A. WOLFE, W. G. NICKLING/GEOLOGICAL SURVEY OF CANADA
Ontario fires: B. J. STOCKS ET AL., CLIMATE CHANGE 38: 1-13
Charlottetown flooding: M. M. McCULLOCH ET AL., OPEN FILE 4261, GSC; environment canada
Permafrost: S. L. SMITH AND M. M. BURGESS, CURRENT RESEARCH 1998-E, GSC

top