Permafrost may be mostly invisible underground, but the consequences of its thawing will be anything but.
That's according to a new study that calculates the global economy could lose as much as $43 trillion by the end of the next century due to greenhouse gas emissions from thawing permafrost -- a figure much worse than previously thought.
The study, published Monday in the journal Nature Climate Change, translated the release of carbon dioxide and methane from permafrost into potential economic impacts -- such as the loss of agricultural production and an increase in the cost of health care -- for the first time.
The world's permafrost holds more carbon than is currently in the atmosphere (as much as double, by some estimates), in the form of thousands of years' worth of plant matter that accumulated without fully decomposing, and the Arctic is warming twice as fast as the global average.
If even a portion of the carbon sequestered in the frozen ground is released, it's likely to accelerate the warming trend. The new analysis included permafrost data to factor in that acceleration.
Using the new data, the researchers ran a simulation 100,000 times through the Policy Analysis of the Greenhouse Effect model under the assumption of a business-as-usual scenario on energy and took the average of those calculations.
The results predicted permafrost emissions alone will boost the total economic impact of climate change to $369 trillion by the year 2200, an increase of 13 percent from the previous estimate of $326 trillion.
To put the amount of economic loss in perspective, the $43 trillion figure is more than half the total global economic activity in 2014, which stood at an estimated $77.9 trillion, according to The World Bank. And the study notes that it does not include in its calculations damage to infrastructure and building foundations due to thawing.
On the bright side, the paper's authors say the scenario they are describing is not inevitable. An "aggressive abatement policy" directed toward permafrost emissions could cut losses by $37 trillion, wrote co-authors Dr. Chris Hope from the Cambridge Judge Business School and Kevin Schaefer of the National Snow and Ice Data Center at the University of Colorado.
"These results show just how much we need urgent action to slow the melting of the permafrost in order to minimize the scale of the release of greenhouse gases," Hope said in a statement.
Climate models work by estimating future levels of heat-trapping carbon in the atmosphere and the accompanying temperature change. But those levels depend on future actions: Measures taken to reduce greenhouse gases from other sources, such as the burning of fossil fuels, would alter the outcomes the paper predicts.
"We want to use these models to help us make better decisions -- linking scientific and economic models together is a way to help us do that," Hope said in the release. "We need to estimate how much it will cost if we do nothing, how much it will cost if we do something, and how much we need to spend to cut back greenhouse gases."