As the world heats up and the Arctic takes a hammering from the increasing temperature, most people will think about the disappearing sea ice and the melting of glaciers. But there’s another ticking time bomb on a much bigger scale in the Northern Hemisphere, and that’s the thawing of permafrost.

As the permafrost warms up, it’s expected to start releasing hundreds of billions of tonnes of methane and carbon dioxide into the atmosphere. Now, researchers have for the first time modeled the economic impact this could have, and it’s not looking good. They estimate in a study, published in the journal Nature Climate Change, that the increase in emissions could cause an additional $43 trillion (£27 trillion) worth of economic damage by the end of the next century.

“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,” explains Dr. Chris Hope, one of the co-authors from the University of Cambridge. It’s thought that around 1,700 gigatonnes of carbon are trapped in the permafrost soils in the form of frozen plant matter. As the ground thaws, bacteria start feeding on the organic matter and begin to release that stored carbon back into the atmosphere.

To put things into perspective, the amount trapped in the tundra is around double the amount of carbon emitted by all of humanity since the Industrial Revolution. Clearly, if it were to thaw, the carbon emissions would be catastrophic. Not only that but it’s generally assumed that if the permafrost does start emitting its carbon, it will form a feedback loop. This means that as the planet warms, more of the frozen ground thaws, releasing more carbon that will further increase the global temperature, causing more ground to thaw and so on. It will also no doubt cancel out any gains made by us cutting our emissions.

“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,” explains Hope. “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.”  

That economic damage is judged to be massive. The impact that an increase in flooding and extreme weather will have on the world's economy will manifest itself in the form of reduced agricultural output, damage to infrastructure and an increase in migration, amongst other things. The predicted cost of climate change was already calculated to be $326 trillion (£210 trillion) by 2200, but this new data increases this by 13% to $369 trillion (£237 trillion).   

All this can be avoided, however, if we manage to keep the warming of the planet below 2°C (35.6°F), but it requires that we, as a species, take action against climate change now. This will all come to ahead as the United Nations Climate Change Conference takes place in Paris to try and form a legally binding agreement on climate between countries later this year.