How much Arctic sea ice are you melting? Scientists have the answer

BOULDER, Colo., Nov. 3 (UPI) -- Want to find out how much sea ice you're melting each time you take a road trip or fly across the country?

Now you can find out, thanks to two researchers and their paper on the subject, newly published in the journal Science. Climate scientists Dirk Notz and Julienne Stroeve calculated the impact of CO2 emissions on the extent of the summer sea ice minimum in the Arctic.

Sea ice in the Arctic fluctuates as the seasons change, the maximums and minimums continue to shrink. Most scientists believe man-made climate change is to blame. As CO2 levels rise, so too do temperatures in the ocean and atmosphere.

Despite the scientific consensus on the link between climate change and ice loss, recent explorations of the correlation have buried the link inside complex climate models.

In the new study, Notz and Stroeve looked at the link directly, measuring the relationship carbon-dioxide emissions and the loss of sea ice. They found a quantifiable linear relation.

"So far, climate change has often felt like a rather abstract notion," Stroeve, a researcher at the National Snow and Ice Data Center in Boulder, Col., said in a news release. "Our results allow us to overcome this perception. 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 5 [square meters] of Arctic sea ice to disappear."

For each metric ton of CO2 emitted by any activity anywhere on the planet, 3 square meters of sea ice disappears. For reference, the average car emits 4.7 metric tons of carbon dioxide each year.

By exploring the link more directly and excising climate models, researchers haven't just cut out the middle men, they've solved a problem models couldn't. Models have mostly underestimated sea ice loss; the new research revealed why.

"Put simply, for each ton of carbon dioxide emission, the climate warms a little bit," Notz explained. "To compensate for this warming, the sea-ice edge moves northward to a region with less incoming solar radiation. This then causes the sea-ice area to shrink. Simple geometric reasons cause these processes to combine to the observed linearity."

Unfortunately, this effect becomes dampened in climate models. The realization should help scientists built better predictive sea ice models.

Because current models underestimate sea ice loss, Notz and Julienne Stroeve suggest emissions will have to be curbed even more than previously recommended of an ice-less Arctic summer is to be avoided.