Climate scientists have looked to the heavens for help with their latest decades-long weather forecast. Their conclusion? "Oh, my god."
Science has long struggled to forecast how global temperatures will be affected by a doubling of carbon dioxide levels in the atmosphere compared with pre-industrial times, which looks likely to occur this century. Recent consensus suggests that temperatures will rise by between 1.5 and 5 degrees Celsius (2.7 to 5.4 F). With a rise in CO2 levels to 400 parts per million, up from 280 in the 19th century, the world has warmed by nearly 1 C so far.
By modeling how clouds will be affected by the rising temperatures, a team of Australian and French scientists reported Wednesday in Nature that they expect the temperature rise to be "more than 3 degrees" -- at the upper end of the projected range.
"4C would likely be catastrophic rather than simply dangerous," the report's lead author, Australian climate scientist Steven Sherwood, told the Guardian. "For example, it would make life difficult, if not impossible, in much of the tropics, and would guarantee the eventual melting of the Greenland ice sheet and some of the Antarctic ice sheet."