structural:reformatting, structural:summarization
Relationship to climate change

A severe threat to tundra is global warming, which causes permafrost to thaw. The thawing of the permafrost in a given area on human time scales (decades or centuries) could radically change which species can survive there. It also represents a significant risk to infrastructure built on top of permafrost, such as roads and pipelines.

In locations where dead vegetation and peat have accumulated, there is a risk of wildfire, such as the 1,039 km (401 sq mi) of tundra which burned in 2007 on the north slope of the Brooks Range in Alaska. Such events may both result from and contribute to global warming.

Carbon emissions from permafrost thaw contribute to the same warming which facilitates the thaw, making it a positive climate change feedback. The warming also intensifies Arctic water cycle, and the increased amounts of warmer rain are another factor which increases permafrost thaw depths.

The IPCC Sixth Assessment Report estimates that carbon dioxide and methane released from permafrost could amount to the equivalent of 14–175 billion tonnes of carbon dioxide per 1 °C (1.8 °F) of warming. For comparison, by 2019, annual anthropogenic emission of carbon dioxide alone stood around 40 billion tonnes. A 2018 perspectives article discussing tipping points in the climate system activated around 2 °C (3.6 °F) of global warming suggested that at this threshold, permafrost thaw would add a further 0.09 °C (0.16 °F) to global temperatures by 2100, with a range of 0.04–0.16 °C (0.07–0.29 °F)