Loss of reflective Sea Ice will advance global warming to a catastrophic 2C within 25 years.
“Because the Arctic’s role in regulating the global climate is a critical link in the chain of climate protection it should be the focus of an all-out effort to keep it strong and safe,” Durwood Zaelke, preident of the Institute of Governance and Sustaninable Development.
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Robert Monroe writes fo the Scripps Institution of Oceanography:
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.
An earlier study by the same team calculated that the ice lost in the Arctic between 1979 and 2011 added 6.4 W/m2 to the Arctic, which averaged globally is equivalent to as much as 25 percent of the effect of CO2 during the same time period. Additional research shows that the thicker multi-year ice which survives year to year is down to 1 percent of the existing ice. 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.
For the baseline calculations, the authors assumed that cloud cover would remain constant. However, they calculate that if the loss of the Arctic ice is accompanied by complete loss of cloud cover, the total added warming could be three times greater.
“One of the really interesting, but somewhat expected, aspects of this study was quantifying just how much impact the potential change in cloud coverage has on the amount of reflected sunlight,” said Pistone.
Conversely, if the Arctic experienced complete cloud cover, the total warming could be half as much. Under all scenarios considered, the study concludes that the radiative heating of complete Arctic sea ice loss could substantially accelerate the rate of future global warming. It would advance global warming by 25 years in the baseline scenario. This would drastically shorten the time available to adapt to climate change and the time for achieving carbon neutrality, the authors said.