Rapid Arctic Changes

Dec. 21, 2018

The past five years have been the warmest on record in the Arctic and that the region is warming at twice the rate as the global average. Last February, the North Pole was above freezing. Normally that time of the year, the North Pole is -20 degrees F, but last year it was 35 degrees F. The Arctic is changing exactly the way scientists thought it would but faster than even the most aggressive predictions. In just three years, more than a dozen climate records that had each stood for many decades have crumbled, including those for disappearing summer sea ice, decreasing winter sea ice, warming air and thawing ground.

  • The Arctic climate is changing rapidly, breaking at least a dozen major records in the past three years.
  • Sea ice is disappearing, air temperatures are soaring, permafrost is thawing and glaciers are melting.
  • The swift warming is altering the jet stream and polar vortex, prolonging heat waves, droughts, deep freezes and heavy rains worldwide.

Effects

  • Rapid Arctic warming also tends to reroute the jet stream in ways that could allow punishing weather patterns to linger across North America, central Europe and Asia longer than usual, subjecting millions of people to unyielding heat waves, droughts or relentless storms.
  • Plankton are increasing throughout the southern Arctic Ocean, which may disrupt food chains that support commercial fisheries.
  • The massive ice melt is adding to an enormous blob of freshwater south of Greenland that may be slowing the Gulf Stream, which could significantly change weather patterns for continents on both sides of the Atlantic Ocean.
  • Permafrost—soil that usually remains frozen year-round—has been thawing. Buildings constructed atop permafrost are collapsing, trees are toppling and roads are buckling. Thawing soils also can release large quantities of heat-trapping gases such as methane into the atmosphere. When the organic matter that has been locked in permafrost for thousands of years thaws, bacteria break it down into carbon dioxide (if oxygen is present) or methane (if it is not). Arctic permafrost contains about twice as much carbon as the atmosphere holds now, so widespread thaw could greatly exacerbate global warming—which would lead to even faster thaw.
  • In addition to reducing albedo, the reflective quality of white ice, waning and thinning sea ice provides less of a barrier for the ocean’s heat to enter the air. The jet stream’s wild north-south swings also brought record pulses of warmth and moisture to far northern latitudes. Scientists and Arctic residents often fail to appreciate the strong effects that the extra moisture can create. For starters, water vapor is a greenhouse gas, so in a dry Arctic winter atmosphere, a little more moisture can trap substantially more heat. Moreover, when that moisture condenses into clouds, it releases latent heat, further warming the air. Finally, more clouds trap more warmth below them, one more factor contributing to the Arctic meltdown.
  • Strong warm-ups in the Arctic’s lower atmosphere can affect winds in the jet stream and even higher, in the stratosphere, home to the polar vortex wind pattern that circles the Arctic. Northward peaks and southward valleys in the bending jet stream generate the high- and low-pressure centers we see on weather maps as a capital H or L. The bends control our weather in the Northern Hemisphere. But if extremely large bends occur more often, we can expect to see an uptick in extreme conditions where billions of people live. That is because large bends in the jet stream tend to progress more slowly from west to east, causing the weather systems they create to hang around longer. Think prolonged heat waves, relentless rains and stalled tropical storms like Hurricane Harvey, which swamped Houston in August 2017—as well as more intense fire seasons like the one in California, also in 2017.

https://www.scientificamerican.com/article/the-arctic-is-breaking-climate-records-altering-weather-worldwide/