Studying Climate Change
G E O W O R L D / S E P T E M B E R 2 O O 9 24 BY HELEN M. COX Climate Mapping C limate change has been high on the agenda of environmentalists and many scientists for some time, but has only more recently appeared on the political agenda. The public is reminded of it almost daily via media images of ice sheets disinte-grating, glaciers receding, polar bears drowning and forest fires erupting. For more specifics, the Intergovernmental Panel on Climate Change (IPCC) 2007 report concludes that warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level. But when it comes to quantifying the warming, fewer details are available. The IPCC reports a change of 0.7° Celsius since the beginning of the 20th century (with most of the warming occurring in the last three decades), but this is a global average. Although the temperature increase is widespread across the globe, regional temperature changes show significant depar-ture from this average. Surface warmings in the mid to high latitudes of the northern hemisphere (including North America and Europe) are a little more than 1° Celsius, the equato-rial region and southern oceans are experiencing lesser Figure 1. A map shows cooperative weather-station locations within Arizona, California, Nevada, Oregon and Washington. A New Tool Mixes Weather Data and GIS