Arctic: Arctic Melt Progresses

The Arctic ice cap continues to melt following the same pattern seen since 2007.  The Arctic is about one million square kilometers under the average ice cover.  An area the size of Texas and New Mexico combined is open water now, that used to be covered in ice.  This area added open water area is absorbing solar radiation and further warming the Arctic. This solar heating feedback has been in place since  2007.

Earlier this spring, much of the ice cover was at less than 100% coverage, indicating thin and easily melted ice. This created the expectation that a new record low in summer ice area would be set this coming September. The current conditions point towards coming close, and maybe just passing the record low of 2007.

As interesting as it is to watch for records to be broken, it is more important to be aware of the recurring pattern we have seen each year since 2007.  Each summer since then, the Kara, Leptev, East Siberian, Chuchki, and Beaufort seas have become virtually ice free. Not long ago, these seas were mostly ice bound year round. These shallow seas are now absorbing solar energy each summer that they did not before. This feedback loop is expected to continue, and in time, to lead to the complete melting of the Arctic in the summer. 

Notice the areas colored red, yellow, orange, and green. Those are areas where the ice is covering the water at less than 100%. Sea Ice Extent data includes those areas as within the extent area, giving a false impression of the amount of ice. Because these areas of less than 100% ice coverage are within the Arctic Basin, I expect some significant melting to occur this year or next. At the end of each of the recent summers, the Arctic Basin melted back from its area of 4 msk to about 2.5 msk, with the rest of the Arctic Ocean being mostly ice free, giving a total ice area of 3.0 msk. The Arctic Basin is the next area to begin showing year to year increased open ocean when the annual summer ice minimum is reached. 

The climatologists differ on their projections of when the summer ice minimum will be zero.  Some say 2020. Some say 2030. Some say 2040. A few years ago, many said 2100, but almost none say that now. From a climate change point of view, Whether it happens in 2020, 2030, or 2040, matters little. The main thing is that continued global warming is projected, and no process is known that may reverse the trend. The past increase in atmospheric CO2 to today's level of 393 ppm is seen as the only explanation for the recent warming.

Projected levels of CO2 to 415 ppm by 2020, 445 by 2030, and 475 by 2040, points to not only continued global warming, but to an increased  rate of warming.  CO2 is expected to rise at 3 ppm per year at least if nothing is done.

How warm will it get before it stabilizes? That is the big question. If it stabilizes at the type of climate that existed the last time the Earth had 400 ppm in its atmosphere, then that would be the climate of the Pliocene.  The Pliocene was 3.5 mya. The climate was much warmer. There was no ice on Greenland. Antarctica had less ice. The oceans were 30 meters (90 ft) deeper.

It could stabilize at a level not as warm as the Pliocene with more ice being retained.  However, CO2 levels will soon be going far above the levels seen in the Pliocene.

What do you think are the possible and likely results?