Study of Subsurface Rocks Confirms Earth’s Warming Trend

A new 300-site survey of bore hole temperatures spanning four continents has confirmed what most scientists already believe--that the Earth is getting warmer and that the rate of warming has been increasing since 1900. The temperature of rock at various depths in the bore holes allows surface temperatures in the past to be calculated. Subsurface temperatures confirm that the average global temperature has increased by 1.8 degrees Fahrenheit over the last five centuries, with half that increase occurring in the last 100 years, geologist Henry N. Pollack of the University of Michigan told a San Francisco meeting of the American Geophysical Union.

If greenhouse emissions continue to increase, he said, the average should increase another 1.8 degrees Fahrenheit by 2050. “This estimate is not based on model calculations, but a projection of actual data,” he said.