​Arctic air is warming, causing scientists to worry that melting arctic ice and snow could also lead to a sudden permafrost thaw and release of carbon dioxide (CO2) and methane (CH4) that forms a climate tipping point or feedback loop. Thawing of permafrost has been linked to releasing zombie viruses not seen in millennia and the feedback loop mentioned in the recent IPCC report and COP27 focused on the release of CO2. This is something that US leaders hope the 2022 climate change bill (Inflation Reduction Act) could help avoid, but the trigger temperature may be coming sooner than expected.

In 2008, Tim Lenton published a groundbreaking paper on tipping points. Permafrost was left off the list at the time. But since then, additional research has shown that this truly enormous store of carbon is far more susceptible to global warming than we just recently believed.

If the permafrost that covers much of the northern hemisphere were to reach this tipping point, it would add many gigatons of greenhouse gas into our atmosphere, significantly worsening climate change, and threatening many of the other climate tipping points.

PBS Terra