A team of American and Canadian researchers has found proof of global warming: the temperature of the Earth?s crust is increasing at a remarkable rate. ?We can now say we truly have global warming,? says Dr. Hugo Beltrami, a geophysicist at St. Francis Xavier University in Nova Scotia.
Until now most data on global warming has been obtained from the atmosphere, polar icecaps and oceans, but Beltrami?s team looked at continental rocks, which cover about 30% of the planet?s surface. They studied 616 deep bore holes that were drilled into rock formations from Africa to the Arctic and found evidence of a sharp rise in temperature over the past 500 years.