Arctic sea ice reaches record low for the second year in a row, scientists are worried
A record low wintertime maximum extent has been recorded for Arctic sea ice. It’s the second year in a row that the ice cap on top of the Arctic Ocean has shown its smallest maximum extent since satellite records began, and the news follows record high temperatures in December, January, and February in the Arctic and around the globe.
Arctic wind patterns during January and February brought warm air from the south and prevented expansion of the ice cover, however the most serious problem in the long run is warming ocean temperatures.
“It is likely that we’re going to keep seeing smaller wintertime maximums in the future because in addition to a warmer atmosphere, the ocean has also warmed up. That warmer ocean will not let the ice edge expand as far south as it used to,” said Walt Meier, a sea ice scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Although the maximum reach of the sea ice can vary a lot each year depending on winter weather conditions, we’re seeing a significant downward trend, and that’s ultimately related to the warming atmosphere and oceans.”
That trend has resulted in a loss of 620,000 square miles of winter sea ice cover, an area more than twice the size of Texas.
How ice protects Earth
During spring and summer the ice cap shrinks before regrowing in the fall and winter months. It reaches its maximum extent between February and April, and according to scientists at the NASA-supported National Snow and Ice Data Center (NSIDC) the 2016 extent peaked at 5.607 million square miles 14.52 million square kilometers). The 13 smallest maximum extents on record have happened in the last 13 years.
Along with concerns about rising sea levels, the loss of the ice is itself a problem, since Arctic sea ice helps to maintain Earth’s temperature, its bright white surface reflecting solar energy that would otherwise be absorbed by the ocean. This is especially a problem in summer. In the winter, when the Arctic Circle doesn’t see sunrise for months, the results of missing sea ice is most impactful in the atmosphere, according to Jennifer Francis, a climate scientist at Rutgers University.
“In places where sea ice has been lost, those areas of open water will put more heat into the atmosphere because the air is much colder than unfrozen sea water,” Francis said. “As winter sea ice disappears, areas of unusually warm air temperatures in the Arctic will expand. These are also areas of increased evaporation, and the resulting water vapor will contribute to increased cloudiness, which in winter, further warms the surface.”
Whether a low summer maximum will be recorded depends more on summer weather conditions than it does on the winter level. But whatever happens in summer, it’s fair to say (at the very least) that things aren’t looking good.
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Image credit: NASA Goddard
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