Thawing Permafrost Could Leach Microbes, Chemicals Into Environment

In Brief:

Scientists are turning to a combination of data collected from the air, land, and space to get a more complete picture of how climate change is affecting the planet’s frozen regions.

Trapped within Earth’s permafrost – ground that remains frozen for a minimum of two years – are untold quantities of greenhouse gases, microbes, and chemicals, including the now-banned pesticide DDT. As the planet warms, permafrost is thawing at an increasing rate, and scientists face a host of uncertainties when trying to determine the potential effects of the thaw.

A paper published earlier this year in the journal Nature Reviews Earth & Environment looked at the current state of permafrost research. Along with highlighting conclusions about permafrost thaw, the paper focuses on how researchers are seeking to address the questions surrounding it.

Infrastructure is already affected: Thawing permafrost has led to giant sinkholes, slumping telephone poles, damaged roads and runways, and toppled trees. More difficult to see is what has been trapped in permafrost’s mix of soil, ice, and dead organic matter. Research has looked at how chemicals like DDT and microbes – some of which have been frozen for thousands, if not millions, of years – could be released from thawing permafrost.

Then there is thawing permafrost’s effect on the planet’s carbon: Arctic permafrost alone holds an estimated 1,700 billion metric tons of carbon, including methane and carbon dioxide. That’s roughly 51 times the amount of carbon the world released as fossil fuel emissions in 2019. Plant matter frozen in permafrost doesn’t decay, but when permafrost thaws, microbes within the dead plant material start to break the matter down, releasing carbon into the atmosphere.

“Current models predict that we’ll see a pulse of carbon released from the permafrost to the atmosphere within the next hundred years, potentially sooner,” said Kimberley Miner, a climate researcher at NASA’s Jet Propulsion Laboratory in Southern California and lead author of the paper. But key details – such as the quantity, specific source, and duration of the carbon release – remain unclear.

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