Climate change — the Arctic Report

The National Oceanic and Atmospheric Adminstration (NOAA) just published their annual Arctic Report Card for 2016.  If this was for a kid in school, his grades would need some serious attention.  NOAA’s one-line summary of the 60-page report is:

Persistent warming trend and loss of sea ice are triggering extensive Arctic changes.

There is no good news.  It’s all bad.

You could say the Arctic gets an F on their Report Card. But it’s not an F for the Arctic.  The F grade is for us; we are the ones that are failing.

Take a look at the subject areas where the Arctic is having the most trouble:

  • Arctic air temperatures continue to increase at double the rate of global increases. The average October-November 2016 air temperature in the lower atmosphere in the central Arctic was 6C above the 1981-2010 climate average. Daily weather records were exceeded all over the Arctic especially near the Kara sea, Svalbord, and northern Canada, which were up to 14C higher than normal;
  • From mid-October to late-November, the sea ice extent was the lowest observed since the beginning of the satellite record in 1979;
  • Sea surface temperatures in August 2016 were up to +5C warmer than the 1982-2010 August mean in regions of the Barents and Chukchi seas, and off the east and west coasts of Greenland;
  • In 2016, new record lows for terrestrial snow cover extent were measured for the North American Arctic, with the May snow cover falling below 4 millon km2 for the first time in the satellite era;
  • Current data indicate that certain areas of the Arctic shelves experience prolonged ocean acidification events in shallow bottom waters. New analyses suggest that these corrosive conditions have been expanding deeper into the Arctic Basin over the last several decades.

The Greenland ice sheet deserves special attention.

This ice sheet is the second largest on the planet–only the Antactic ice sheet is larger. The Greenland ice sheet holds around 2500 trillion tons of frozen water.  And yes its melting.

 

This is not good

Because it’s not floating ice–which doesn’t change sea levels as it melts, when the Greenland ice melts it directly affects sea levels.

So how fast is it melting?  The Arctic Report Card has a graph which is not difficult to figure out.

So yes this is more bad news on the report card.  A Gt is a gigatonne–a billion tonnes. So the Greenland ice sheet has lost more than 3000 billion tonnes of ice during the last 15 years. So that’s roughly 200 billion tonnes of ice melting into the sea each year.  More recent measurements show that melting has now risen to around 260 Gt a year.  Makes sense: the Earth is getting warmer, and for reasons not entirely understood, the Arctic is warming faster than regions farther south.

So should we be worried?  Definitely; but not directly by what’s going on in Greenland.

The ice sheet is so massive– it weighs in at around 2.5 million gigatons–that it’s going to take several thousand years of global warming before it’s completely melted.

But each year, more and more ice keeps melting, and each year, sea levels across the globe rise just a tiny bit more.

One aspect worth noting is that a recent report from NASA’s Jet Propulsion Lab found that the melting of the Greenland and Antarctic ice sheets is having a measurable effect on the Earth’s axis of rotation. The declining mass of the huge ice sheets is actually having an impact on the way the Earth moves around the sun.  An expert at the Center for Space Research at the University of Texas is quoted as saying that there is nothing to worry about. “It’s just another interesting effect of climate change.”

Right. There’s nothing to worry about.

The methane factor

Northern permafrost zone soils contain huge amounts of organic carbon, about twice as much as is currently contained in the atmosphere. Warming conditions promote microbial conversion of permafrost carbon into carbon dioxide and methane that are released into the atmosphere in an accelerating feedback mechanism driven by climate change.

In other words, as global warming raises temperatures, more carbon dioxide and methane are released from the thawing permafrost soils; and as more of these gases are dispersed into the atmosphere, the more intense the warming in turn becomes.

The climate change focus up until now has been mainly on carbon dioxide–a gas that stays in the atmosphere for a longer time and which has a strong impact on global warming. But the spotlight now is shifting to methane.

This a powerful greenhouse gas with an impact more than 20 times stronger than CO2.  It doesn’t stay in the atmosphere as long as CO2, but methane emissions have been rising almost exponentially, and the impact of this gas on global warming is now becoming just as important as CO2.

The 2016 Arctic Report Card is about persistence–an admirable trait in a student, but in the context of the Arctic environment, what is persisting is a warming trend that has potentially catastrophic consequences.

 

 

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