Dirk Notz calculates that for every person who drives a car 1,000 miles or takes a round-trip flight from New York to London, about 32 square feet of sea ice vanishes from the Arctic.
Researchers have long documented that human-fueled carbon dioxide emissions contribute to the overall warming of the planet — and, by extension, accelerate the diminishing of sea ice in the Arctic each year. But in a paper published on Thursday in the journal Science, Notz and a colleague detail the complex set of calculations that allowed them to estimate how much Arctic sea ice melts for every metric ton of carbon dioxide emitted into the atmosphere.
Their answer? About 32 square feet.
The result, if accurate, helps illustrate how individual actions shape what often can seem a faraway problem. The average American, for instance, emits more than 17 tons of carbon each year, according to the World Bank. That would amount to the melting of about 516 square feet of ice in the Arctic, or about enough to cover the floor plan of a 500-square-foot apartment.
“This makes it possible to intuitively grasp how we all contribute to global warming,” said Notz, a climate scientist at the Max Planck Institute for Meteorology in Germany, who co-wrote the paper with Julienne Stroeve, a senior research scientist with the National Snow and Ice Data Center in Colorado. “It’s really possible to translate how individual actions contribute to sea-ice loss.”
The researchers also argue that the linear relationship between carbon dioxide emissions and the amount of ice melting might serve as a good predictor of when the Arctic will be completely free of ice during September, the lowest month each year for Arctic sea ice, a development many scientists expect to happen over the next several decades, possibly even by 2030. Sea ice extent in the Arctic measured as low as it has ever has in late October, and air surface temperatures have shown record warmth. It is difficult to project what the current ice depletion means for next year, but there is an unmistakable, long-term trend toward less ice in the Arctic.
Notz and Stroeve suggest that it might be less a question of timing and more a question of how much CO2 the world emits. At the current rate of emissions, the Arctic could be free of ice during the late summer by the middle of this century.
Meier said the idea behind Thursday’s study provides a powerful way to visualize how each of us plays a role in a problem that might seem far away, but ultimately isn’t.