A new study by NASA scientists finds that the world's temperature is reaching a level that has not been seen in thousands of years. The study, led by James Hansen of NASA's Goddard Institute for Space Studies, N.Y., along with scientists from other organizations concludes that, because of a rapid warming trend over the past 30 years, the Earth is now reaching and passing through the warmest levels in the current interglacial period, which has lasted nearly 12,000 years. An "interglacial period" is a time in the Earth's history when the area of Earth covered by glaciers was similar or...