SOURCE: Scripps Institution of Oceanography

DATE: July 22, 2019

SNIP: Losing the remaining Arctic sea ice and its ability to reflect incoming solar energy back to space would be equivalent to adding one trillion tons of CO2 to the atmosphere, on top of the 2.4 trillion tons emitted since the Industrial Age, according to current and former researchers from Scripps Institution of Oceanography at the University of California San Diego.

At current rates, this roughly equates to 25 years of global CO2 emissions. It would consequently speed up the arrival of a global threshold of warming of 2ºC beyond temperatures the world experienced before the Industrial Revolution. Scientists and analysts, including the authors of an Intergovernmental Panel on Climate Change Special Report released in October 2018, have stated that the planet runs the risk of catastrophic damage ranging from more intense heat waves and coastal flooding to extinction of terrestrial species and threats to food supply if that threshold is passed.

The results were published June 20 in the journal Geophysical Research Letters. The authors of the study conclude that the loss of sea ice will add a globally-averaged 0.7 watts per square meter (W/m2) of solar heating to the Earth system, 0.21 W/m2 of which has already occurred between 1979 and 2016.

The amount of additional heat introduced into the Earth system because of Arctic melt is equivalent to an increase in CO2 concentration from 400 to 456.7 parts per million.

“Losing the reflective power of Arctic sea ice will lead to warming equivalent to one trillion tons of CO2 and advance the 2ºC threshold by 25 years. Any rational policy would make preventing this a top climate priority for world leaders,” said Ramanathan, a professor of atmospheric and climate sciences at Scripps.

There is great uncertainty about the timing of when the Arctic could become seasonally ice-free, with some research suggesting that recent trends could lead to an ice-free Arctic as early as the 2020s and others suggesting 2030 or substantially later depending on factors including future warming and natural variability.