Measurements reveal the relationship between individual carbon dioxide (CO2) emissions and the Arctic's shrinking summer sea ice.

‘The rapid retreat of Arctic sea ice is one of the most direct indicators of the ongoing climate change on our planet.’

The rapid retreat of Arctic sea ice is one of the most direct indicators of the ongoing climate change on our planet. Over the past forty years, the ice cover in summer has shrunk by more than half, with climate model simulations predicting that the remaining half might be gone by mid-century unless greenhouse gas emissions are reduced rapidly. However, a number of studies have indicated that climate models underestimate the loss of Arctic sea ice, which is why the models might not be the most suitable tools to quantify the future evolution of the ice cover. 




To address this issue, a new study in the journal Science now derives the future evolution of Arctic summer sea ice directly from the observational record. To do so, the authors examine the link between carbon-dioxide emissions and the area of Arctic summer sea ice, and find that both are linearly related. "The observed numbers are very simple", explains lead author Dirk Notz.
"So far, climate change has often felt like a rather abstract notion. Our results allow us to overcome this perception", says co-author Julienne Stroeve. For example, it is now straight-forward to calculate that the carbon dioxide emissions for each seat on a return flight from, say, London to San Francisco causes about five square metres of Arctic sea ice to disappear."
While climate models also simulate the observed linear relationship between sea ice area and CO2 emissions, they usually have a much lower sensitivity of the ice cover than has been observed. The Science study finds that this is most likely because the models underestimate the atmospheric warming in the Arctic that is induced by a given carbon-dioxide emission. "It seems that it's not primarily the sea ice models that are responsible for the mismatch. The ice just melts too slowly in the models because their Arctic warming is too weak", says Stroeve.
Another 1000 gigatonnes of CO2 and sea ice will be stripped by September
Advertisement
Source-Newswise