Climate change cost up to £54 trillion ($70 trillion) more than previously calculated as the fallout from melting Arctic ice worsens.
As the Arctic warms, melting permafrost will release more carbon into the atmosphere while the loss of ice and snow will reflect less sunlight back into space.
Together, these effects combine to worsen global warming thanks to a complex interplay and a multitude of factors.
The costs of climate change could be minimised, the researchers claim, if more ambitious climate targets laid out by the Paris Agreement are met.
If the global temperature rise could be kept to under 1.5°C above pre-industrial levels, then the costs of arctic feedback effects would drop to only £19.3 trillion ($25 trillion).
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Climate change will be accelerated — and cost up to £54 trillion more than previously calculated — thanks to feedback effects from Arctic thawing (stock image)
The majority of previous climate policy studies have made two consistent assumptions in their models of changing climates.
The first is that there will be no positive feedback effect generated as thawing permafrost releases additional carbon into the atmosphere.
Meanwhile, the second assumption relates to the Earth's so-called 'albedo', the proportion of sunlight reflected back into space compared with the amount of energy the Earth absorbs.
As the coverage from white sea ice and snow on land both decline, more energy from the sun is expected to be absorbed by the ocean and land.
Most studies have assumed, however, that the surface albedo feedback will be constant.
Now, researchers have used state-of-the-art physical models to better explore the strength of both the permafrost carbon feedback (PCF) and the surface albedo feedback (SAF) in warming climates.
In contrast to previous assumptions, the researchers found that of the two feedbacks, those from permafrost carbon release are stronger — but both are complex.
'Arctic sea ice and land snow currently contribute around a third each to the global albedo feedback,' said lead author Dmitry Yumashev, a climate scientist at Lancaster University.
'These two components are set to peak for global temperatures within the range covered by the Paris Agreement, but if the climate warms further, the summer and spring sea ice and land snow covers will retreat further north and the albedo feedback will actually weaken.'
In contrast, he added, the permafrost feedback will grow 'progressively stronger in warmer climates.'
This permafrost feedback effect also includes a varying lag time between a given temperature rise and corresponding release of additional carbon emissions.
These findings alter our understanding of how Arctic warming will affect both the global climate and the world economy.
As the coverage from white sea ice and snow on land both decline, more energy from the sun is expected to be absorbed by the darker exposed ocean and land (stock image)
'Compared with zero PCF and constant SAF from present-day climate — legacy values used in climate policy modelling to this point — the combined nonlinear PCF and SAF cause significant extra warming globally under low and medium emissions scenarios,' Dr Yumashev said.
In all the scenarios modelled, factoring in the complex Arctic feedbacks increases the total economic costs of climate change.
The additional costs stem manly from the additional temperature-controlled effects
