By Justin Schellenberg, November 24 2017 —
A recent study by the University of Calgary’s Cryosphere Climate Research Group found that estimates of seasonal Arctic sea ice thickness are likely much lower than previously thought.
According to the study, measurements made by the European Space Agency (ESA) with their CryoSat 2 satellite may be off by a substantial amount.
“The estimates that have been made to date perhaps 10–20 per cent overestimated ice thickness,” said John Yackel, co-author of the study and geography professor at the U of C. “It’s not necessarily that the melting has occurred faster, it’s simply that the satellite has likely been distinctly overestimating the thickness of the ice.”
Fourth-year geography PhD student and lead author of the study Vishnu Nandan said the reason the ESA estimates are off is because it did not take into account the amount of salt in the snow.
“From my previous publications, we realized that salt on snow is a big problem,” Nandan said. “[The ESA] know that snow salinity is a factor but they never knew, or might have underestimated, the impact of snow salinity affecting the ice thickness estimates.”
The study used 53,000 measurements collected over 15 years to calculate its findings.
Nandan added that the salinity of the snow scatters the signal from the satellite. Because of this, he believes the estimates of when the first ice-free Arctic summer will occur are off by approximately 10 years.
“The models say that [an ice-free Arctic summer] will happen by around 2050,” Nandan said. “We likely feel that it could be much earlier.”
An ice-free Arctic summer could have drastic effects for regions all around the world.
“When sea ice starts melting, you have more ocean exposed to sunlight. The ocean absorbs all the sunlight,” he said. “The polar ocean starts warming, which affects the mid-Atlantic. When the mid-Atlantic ocean gets warmer you get variations in monsoon seasons in Asia. You get frequent storms.”
Nandan also said an ice-free Arctic summer will likely lead to more tourism, which would lead to more pollution.
The study has received widespread attention since its publication, including being mentioned in the New York Times. Yackel says the attention is well-deserved for Nandan.
“This paper is definitely his most significant journal publication to date for his PhD and it certainly has attracted quite a bit of attention from some of the top ice scientists around,” Yackel said. “It’s a great accomplishment and a great feather in his cap.”
Nandan said it was not his intention to garner praise from the study, but it’s a nice surprise.
“When you work hard towards your PhD, at some point in time your contributions should be known and should be credited,” Nandan said. “It’s like a cherry on top.”