“Sea Levels Dropped in 2010.” That’s what the headline should have read. Instead, NASA tried to hide this startling information under the nondescript headline “NASA Satellites Detect Pothole On Road to Higher Seas.” (See http://www.jpl.nasa.gov/news/news.cfm?release=2011-262)
The story begins as yet another global warming horror story, explaining how “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.”
Red line shows increase in global sea level since the early 1990s. Sea level has risen by a little more than an inch each decade, or about 3 mm per year. The recent drop of nearly one quarter inch (½ cm), is attributable to the switch from El Niño to La Niña. (Credit: S. Nerem, University of Colorado)
While the rise of the global ocean has been remarkably steady for most of the last 18 years, the article continues, (undoubtedly due to global warming caused by we nasty humans, of course) “every once in a while, sea level rise hits a speed bump. This past year, it’s been more like a pothole: between last summer and this one, global sea level actually fell by about a quarter of an inch, or half a centimeter.”
They kind of snuck that in there, didn’t they? Sea levels actually fell!
So what does it mean? “You can blame it on the cycle of El Niño and La Niña in the Pacific,” explains climate scientist Josh Willis of NASA’s Jet Propulsion Laboratory, in Pasadena, California.
One of the strongest La Niñas in recent memory “changed rainfall patterns all across the globe, bringing massive floods to places like Australia and the Amazon basin, and drought to the southern United States.” This extra rain piled onto the continents in the early parts of 2011.
Uh huh. Rising sea levels are caused by humans. But falling sea levels are caused by natural forces.
Where did that extra water come from? “You guessed it–the ocean. Each year, huge amounts of water are evaporated from the ocean. While most of it falls right back into the ocean as rain, some of it falls over land.”
“This year, the continents got an extra dose of rain, so much so that global sea levels actually fell over most of the last year,” says Carmen Boening, a JPL oceanographer and climate scientist. But for those who might argue that these data show us entering a long-term period of decline in global sea level, Willis cautions that sea level drops such as this one cannot last, and over the long-run, the trend remains solidly up. Water flows downhill, and the extra rain will eventually find its way back to the sea. When it does, global sea level will rise again.”
Maybe. But what if that precipitation remains locked up on land as ice? Look at the record snowfall throughout the Western United States this past winter. That’s how ice ages begin. If that sort of snowfall persists, sea levels will continue falling and won’t rise again until the end of the next ice age.
“We’re heating up the planet, and in the end that means more sea level rise,” says Willis. “But El Niño and La Niña always take us on a rainfall rollercoaster, and in years like this they give us sea-level whiplash.”
As far as I’m concerned this article is totally biased toward global warming, not something one likes to see coming from NASA.