Notícias do futuro

NSIDC bombshell: Thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s, releasing 100 billion tons of carbon by 2100 - Study underestimates impacts with conservative assumptions

Figure:  Carbon emission (in billions of tons of carbon a year) from thawing permafrost.

The thaw and release of carbon currently frozen in permafrost will increase atmospheric CO2 concentrations and amplify surface warming to initiate a positive permafrost carbon feedback (PCF) on climate…. [Our] estimate may be low because it does not account for amplified surface warming due to the PCF itself….  We predict that the PCF will change the arctic from a carbon sink to a source after the mid-2020s and is strong enough to cancel 42–88% of the total global land sink. The thaw and decay of permafrost carbon is irreversible and accounting for the PCF will require larger reductions in fossil fuel emissions to reach a target atmospheric CO2 concentration.

That’s the stunning conclusion from “Amount and timing of permafrost carbon release in response to climate warming” (subs. req’d), a major new study in Tellus by NOAA and the National Snow and Ice Data Center (NSIDC).  As we’ll see, the figure above is almost certainly too conservative post-2080.