Melting permafrost threatens climate rescue plan

PARIS: Global targets aimed at warding off runaway planetary warming could be breached sooner than expected, experts warned Monday, as gases released by melting permafrost threaten to undermine human efforts to avert climate disaster.

Under the current rescue plan, outlined in the 2015 Paris climate treaty, countries have agreed to limit global temperature rises to “well below” two degrees Celsius, and 1.5C if deemed possible.

That course of action assumes that dealing with manmade greenhouse gases — whether by slowing their emissions or removing them from the atmosphere — will be enough to bring global warming under control. What climate models do not allow for are scenarios in which Earth begins to contribute to the problem, new research shows.

A team of experts from the International Institute for Applied Systems Analysis in Austria said Monday they had for the first time included projected emissions from melting permafrost in global climate change models, and the results prompted concern.

“Permafrost carbon release is caused by global warming, and will certainly diminish the budget of CO2 we can emit while staying below a certain level of global warming,” said IIASA research scholar and lead study author Thomas Gasser.

As reliance on fossil fuels persists, scientists have calculated that we are likely to “overshoot” the Paris temperature targets in the short to medium term. With only 1C of warming above pre-industrial levels so far, the world’s permafrost is already thawing, albeit slowly.

But the rate of that melting is sure to accelerate as Earth continues to heat up.Gasser warned that the overshoot scenario would leave the planet even more vulnerable to permafrost emissions and, in a vicious feedback loop, even more warming.

In fact, under some models run in the study, published in the journal Nature Geoscience, we have already missed the 1.5C target as a result of permafrost emissions. “Overshooting is a risky strategy, and getting back to lower levels after overshooting will be extremely difficult,” Gasser told AFP.“We have to prepare ourselves for the possibility that we may never get back to safer levels of warming.”