A new analysis published on April 23 in Nature Communications suggests that if nations fail to meet commitments set out in the Paris agreement, climate change related to the Arctic warming and the associated costs will increase by almost 5 per cent. The author’s claim this is the first study to estimate the potential economic impact of global warming owing to sea ice and land snow loss.
The researchers, led by Dmitry Yumashev from the Pentland Centre for Sustainability in Business at the University of Lancaster, used advanced computer models to calculate the impacts of accelerated climate change due to arctic feedbacks; more specifically, permafrost melting and increased absorption of solar heat by the earth’s surface
How do Arctic feedbacks affect global warming
Permafrost occurs in colder regions and is mainly the deeper layers of soil that stay well below freezing even during summer months. These areas act as a reservoir for large volumes of carbon dioxide (CO2) and methane (CH4). Therefore, as permafrost thaws, the potent greenhouse gases are released.
Recent studies have shown the relationship between permafrost melting and global warming is nonlinear owing to the positive feedback loop – the release of greenhouse gases further exacerbates global warming, which in turn, accelerates thawing.
Another snow-related factor can also contribute to warmer global temperatures. Darker ocean and land areas absorb more solar energy than white sea ice and land covered by snow. Therefore, as snow cover decreases, so too does so-called albedo – the amount of sunlight reflected off the surface of the earth without being absorbed. And the resulting increase in the absorption of solar energy leads to further warming.
The cumulative effects of both of these accelerating processes could be much greater than once thought. To date, the values used in climate policy models have significantly underestimated both. This will mean problems caused by climate change could be both more difficult and more costly to solve than expected.
Modelling the impact of increased permafrost thaw and reduced albedo
The team of researchers performed simulations using state of the art software in the US and in the UK. Based on the most advanced computer models, they quantified the impact of additional CO2 released from thawing permafrost and reduced albedo and then applied established economic impact models to assess the potential costs
The researchers analysed various emissions scenarios: low (meeting the Paris Agreement’s 1.5 and 2 degrees Celcius target relative to pre-industrial conditions by 2100), medium (mitigating global warming to 3 degrees Celius), and high (business-as-usual, which is expected to increase global temperature by at least 4 degrees Celcius by 2021).
Potential economic and societal impacts
The researchers found that permafrost thawing – and in particular, the associated CO2 emissions – is a major concern. According to the study, once global warming exceeds the 1.5 degrees Celcius target set out in the Paris Climate Agreement, the amount of carbon being released could increase considerably.
On the business-as-usual trajectory, this could boost global climate-driven impacts by $70tn between now and 2300. Even at 1.5 to 2 degrees Celsius, there are significant climate-related impacts.
And this will also add to global inequality – most of the adverse effects of global warming are borne by low-income countries in warmer regions, such as India.
(1) Yumashev, D. et al. Climate policy implications of nonlinear decline of Arctic land permafrost and other cryosphere elements. Nature Communications (2019). DOI: 10.1038/s41467-019-09863-x