Monday, 15 January 2007
Comparison of glacier-inferred temperatures with observations and climate model simulations
Exhibit Hall C (Henry B. Gonzalez Convention Center)
A reconstructed temperature history for different regions of the globe was prepared by Oerlemans  from length changes of 169 glaciers. In this study, we compare the glacier-inferred temperature variations over 1900-1990 with observed and climate model simulated temperatures for the global average and for five regions: Southern Hemisphere, Northwest America, Atlantic, Asia, and the Alps. There is reasonable agreement between the glacier-inferred temperature trends and the observed temperature trends for the globe and in four of the five regions (except Northwest America, NWA). The trends for the globe and in these regions are significantly different from zero, cannot be explained by natural variability (again except for NWA), and are consistent with the model-simulated response to anthropogenic forcing in all regions. Hence, it is likely that the glacier length reductions are outside the range of natural variations and due in part to regional warming associated with increasing concentrations of greenhouse gases in the atmosphere.