John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
Since 1979, the region has lost a winter ice cover equal to twice the size of Texas.
With the way the Arctic is warming up, there soon might not be an ice pellet left to wing at a climate-change denier’s noggin. The region’s sea ice has likely reached its maximum extent for the year and—at 5.6 million square miles—it’s the paltriest winter extent in almost four decades of satellite records.
The ice, which was more shrunken than the previous record-setting extent last winter, had endured a powerful atmospheric blow dryer. Air temperatures in places (particularly around the ice’s edges) were more than 10 degrees above average. Mark Serreze, director of the National Snow and Ice Data Center, says in a press release he’s “never seen such a warm, crazy winter in the Arctic,” adding the “heat was relentless.”
Here’s more from NASA, which created the above animation of ice growth from last summer to March 24:
The wind patterns in the Arctic during January and February were also unfavorable to ice growth because they brought warm air from the south and prevented expansion of the ice cover. But ultimately, what will likely play a bigger role in the future trend of Arctic maximum extents is warming ocean waters, [NASA scientist Walt] Meier said.
“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,” Meier said. “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.” Since 1979, that trend has led to a loss of 620,000 square miles of winter sea ice cover, an area more than twice the size of Texas.
A healthy sea-ice cover is important for several reasons: It blocks sunlight from heating up the ocean, for instance, and prevents the seas from evaporating and creating clouds, which can amplify surface-level warming in the winter. Its role in global climate patterns will no doubt become more of a hot topic as the sea-ice declines. Thirteen of the smallest-known wintertime extents, says NASA, have fallen in the last 13 years.