Something is thawing beneath Alaska — and the price tag could be $43 trillion

Alaska’s tundra may look quiet and almost lifeless from above, but beneath the moss and low vegetation sits one of the planet’s largest stores of frozen carbon.

That hidden reserve is becoming increasingly important as the Arctic warms. When permafrost thaws, ancient plant and animal material that has remained frozen for thousands of years can begin to decompose. The process releases greenhouse gases including carbon dioxide and methane, potentially adding to global warming.

A landmark 2015 study by researchers from the University of Cambridge and the University of Colorado estimated that these additional emissions could result in as much as $43 trillion in extra global economic damage by 2200 under the study's A1B emissions scenario.


The number is not a prediction of a future bill or a direct valuation of Alaska’s land. Instead, it represents the researchers’ estimate of additional economic losses associated with greenhouse gases released as Arctic permafrost thaws.

Why Alaska’s permafrost matters to the entire planet

Permafrost is ground that has remained frozen for extended periods, often containing enormous amounts of organic material accumulated over thousands of years.

Researchers estimated that Arctic permafrost soils contain roughly 1,700 gigatonnes of carbon. While that carbon remains frozen, decomposition is largely slowed. Rising temperatures can change that equation.

As frozen soil thaws, microorganisms can break down the previously preserved material. Some of the carbon can then enter the atmosphere as carbon dioxide, while methane can also be produced under oxygen-poor conditions.

That creates a potentially troubling cycle: warming causes thaw, thaw releases greenhouse gases, and those emissions can contribute to additional warming.

How scientists reached the $43 trillion figure

The estimate came from an economic modelling exercise rather than from assigning a price to the permafrost itself.

Cambridge researcher Chris Hope and University of Colorado researcher Kevin Schaefer examined the economic consequences of carbon dioxide and methane released by thawing permafrost. Their research used the PAGE09 integrated assessment model to connect additional greenhouse-gas emissions with projected climate-related damages.

Under the A1B scenario examined in the study, the estimated net present value of climate-change impacts increased from $326 trillion to $369 trillion by 2200 once permafrost emissions were included.

That represented an increase of roughly 13%, or about $43 trillion.

The researchers estimated that approximately $33 trillion of the additional damage was linked to carbon dioxide and around $8 trillion to methane, with the remaining amount attributed to interactions between the gases.

The number comes with a huge range of uncertainty

The $43 trillion figure can sound definitive, but the researchers themselves highlighted substantial uncertainty in the modelling.

Their estimated range for the additional economic impact extended from roughly $3 trillion to $166 trillion at the 5th to 95th percentile.

That wide range reflects the difficulty of predicting how quickly permafrost will thaw, how much carbon will be released, how greenhouse gases will affect future temperatures and how climate change will translate into economic losses over nearly two centuries.

In other words, the study's headline figure is best understood as a modelled estimate under a particular emissions pathway, not a guaranteed outcome.

Why the economic damage would spread far beyond Alaska

Permafrost thaw may occur thousands of kilometres from major population centres, but its potential consequences are global.

Once carbon enters the atmosphere, the resulting greenhouse gases do not remain confined to the Arctic. Additional warming can affect agriculture, human health, ecosystems and energy demand in regions around the world.

The Cambridge researchers also linked greater warming with risks including flooding, extreme weather and additional ice-sheet loss.

That makes the Arctic's frozen ground an unusual climate threat: the carbon is stored locally, but the consequences of releasing it can be worldwide.

Cutting emissions could reduce the damage

The 2015 research also pointed to a potential way of limiting the economic consequences.

The researchers estimated that an aggressive strategy to reduce greenhouse-gas emissions could lower the additional economic impact associated with permafrost thaw by as much as $37 trillion compared with the scenario they analysed.

The implication was clear: limiting overall warming could also reduce the amount of carbon released from thawing permafrost.

What newer research says about thawing permafrost

The original $43 trillion estimate dates back to 2015, so it should not be presented as a current forecast of the eventual cost of Arctic warming.

But subsequent research has added another concern: abrupt permafrost thaw.

Scientists have found that sudden thawing can expose carbon more rapidly than gradual processes captured by some climate models. In certain environments, these changes can also create conditions that favour methane emissions.

That means the future behaviour of permafrost may depend not only on how much the Arctic warms, but also on how quickly and unevenly frozen landscapes change.

Alaska’s tundra is more than frozen soil

The vast Arctic landscape can appear remote from the global climate debate. Yet beneath it lies a carbon reserve capable of influencing the atmosphere far beyond Alaska.

The striking lesson from the Cambridge and Colorado research is therefore not simply the $43 trillion price tag. It is the scale of the connection between a seemingly distant landscape and the global economy.

Permafrost may be frozen ground, but its carbon is part of an active climate system. As Arctic temperatures rise, keeping that carbon locked underground could become increasingly important to limiting the economic and environmental costs of climate change.