Global warming study suggests human causes dating back to 1800s
Monday, April 22, 2013 - 21:11
in Earth & Climate
A long-term global cooling trend ended in the late 19th century, a reversal in temperature that cannot be explained by natural variability alone, according to a new study.The finding stems from 2,000-year-long continental-scale temperature records inferred from tree rings, ice cores, lake sediments and other so-called proxies from around the world. The records show variations in temperature caused...