World temperatures could surge in just two decades to a threshold likely to trigger dangerous disruptions to the earth’s climate, the WWF environmental group said on Sunday. It said the Arctic region was warming fastest, threatening the livelihoods of indigenous hunters by thawing the polar ice-cap and driving species like polar bears toward extinction by the end of the century.‘‘If nothing is done, the earth will have warmed by 2.0 Celsius (3.6 Fahrenheit) above pre-industrial levels by some time between 2026 and 2060,’’ the WWF said in a report. Few scientists have estimated such an early date for a 2.0C rise, seen by the WWF as a threshold that may spur ‘‘dangerous’’ warming, raising sea levels and causing more floods, storms or droughts and driving some species to extinction. World temperatures have already risen by about 0.7C since 1750 with most scientists blaming a build-up of heat-trapping gases like carbon dioxide emitted by burning fossil fuels in factories, power plants and cars. The EU and many other environmental groups say that governments should cap emissions of greenhouse gases to try to prevent a 2.0C temperature rise. —Reuters
