Maybe He Was Right After All!

In 2008, while campaigning for president, Barack Hussein Obama said:

...this was the moment when the rise of the oceans began to slow...

Ann Althouse dubbed that the "Most megalomaniacal line in Barack Obama's speech."


Shockingly, that has come to pass; in 2010 the average sea levels, as measured by the Topex satellite, declined 6 mm, erasing almost two years of sea level rise:

The red line in this image shows the long-term increase in global sea level since satellite altimeters began measuring it in the early 1990s. Since then, sea level has risen by a little more than an inch each decade, or about 3 millimeters per year. While most years have recorded a rise in global sea level, the recent drop of nearly a quarter of an inch, or half a centimeter, is attributable to the switch from El Niño to La Niña conditions in the Pacific. The insets show sea level changes in the Pacific Ocean caused by the recent El Niño and La Niña (see http://sealevel.jpl.nasa.gov/science/elninopdo for more information on these images). Credit: S. Nerem, University of Colorado

Like mercury in a thermometer, ocean waters expand as they warm. This, along with melting glaciers and ice sheets in Greenland and Antarctica, drives sea levels higher over the long term. For the past 18 years, the U.S./French Jason-1, Jason-2 and Topex/Poseidon spacecraft have been monitoring the gradual rise of the world's ocean in response to global warming...

So what does this mean?  Have sea levels begun a long period of decline?  Not bloody likely.  Sea levels have been rising, on average since the end of the last ice age maximum almost 14,000 years ago. Nothing substantial has changed with anthropogenic global warming to change that.  CO2 continues to flow into the atmosphere in increasing amounts.

No, the temporary decline was caused by a relatively small decline in the heat content of the ocean, which was caused by a switch from ElNiño to La Niña conditions.  The heat capacity of water is about 3,500 times the heat capacity of air on a volume basis, so the heat shed by the ocean in 2010 represents a large loss in total heat world wide, which had to be transferred through the atmosphere into space, no doubt contributing to the near record high global temperatures in 2010.  Caused by the ocean losing heat...