New projections show global warming is accelerating well past the recommended 1.5 degree Celsius target. A new study published in Reviews of Geophysics concludes that the absolute best case scenario is now about 1 degree Celsius hotter than scientists previously thought.
Scientists have long debated exactly how much the planet will heat up. The general consensus was between 1.5 and 4.5 degrees Celsius hotter than it was in pre-industrial times. The new study tightens that window from 2.6 to 4.1 degrees Celsius.
Twenty-five scientists around the world collaborated on the paper. They based their study on current warming trends, data from ancient climates and the most up-to-date understanding of factors that can slow or speed up climate change. After examining all the data, the international group of experts readjusted the bottom range after noting that the temperature is already up 1.2 degrees Celsius above pre-industrial levels. If emission levels continue unchecked, atmospheric carbon dioxide could easily double before the year 2100.
Even if global warming reaches the midpoint of the range at 3 degrees Celsius, humanity will be in trouble. It will be the equivalent of a five-alarm fire for the planet, said Kate Marvel, a physicist at NASA’s Goddard Institute of Space Studies and Columbia University.
“The main message is that unfortunately we can’t expect that luck will save us from climate change,” said Reto Knutti, professor of climate physics at ETH Zurich’s Institute for Atmospheric and Climate Science. “The good thing is that we’ve somewhat narrowed the range of future long-term warming, the bad thing is that we can no longer hope or claim that the problem will just magically go away.”
Image via Jürgen Jester