Arctic sea ice has now melted to its lowest summer extent ever recorded in more than 3 decades of satellite measurements (since 1979), according to the National Snow and Ice Data Center and NASA.Â The yellow line on the above image shows the average minimum ice extent between 1979-2010, as measured by satellites. As you can see, this year’s extent is considerably lower.
Each northern hemisphere summer, Arctic sea ice melts to its minimum level for the year before building up again for the winter. NASA explains that over the long term, this summer minimum level has been in decline, and on August 26, 2012, the low level of ice broke the previous record established back in September 2007.
Although this year’s ice melt has already reached a record low, it could carry on melting for several more weeks yet, into mid-to-late September. NSIDC scientist Walt Meier has said, “It’s likely we are going to surpass the record decline by a fair amount this year by the time all is said and done.” He added,Â “In the context of what’s happening in the last several years and throughout the satellite record, it’s an indication that the Arctic sea ice cover is fundamentally changing.”
Scientists say that the Arctic ice cap matters because it’s crucial to keep the polar region cold, which helps to moderate global climate. It’s like an air conditioner for the planet. The white surface of the ice reflects up to 80 percent of the sunlight back to space. When the ice melts, the extra ocean area left by the melt absorbs about 90 percent of the sunlight hitting it. Scientists say that this process has created a positive feedback effect (positive not meaning good in this scientific sense), causing the ocean to heat up and further contribute to accelerated ice melt.
For the diminishing number of climate change skeptics left out there, this is surely some more compelling evidence that climate change is real and happening right now. When do you think this year’s new record low level might be broken again? Unfortunately, it seems highly likely that it won’t be very long at all.
Image: Scientific Visualization Studio, NASA Goddard Space Flight Center