Image from dsearls
It's worse than we thought. In a new study published in the latest issue of Nature, a group of international researchers has determined that sea level rise and ocean temperature trends for 1961 - 2003 are 50 percent larger than previously estimated by the IPCC -- though also 40 percent smaller for 1993 - 2003. Sea levels rose by about 1.5 mm per year during the 42 year span, adding up to a 6.3 cm (or 2.5 in) overall gain.
So the ocean isn't cooling?
These findings rebuke the claims made by some global warming skeptics who have pointed to transitory evidence suggesting oceans might actually be cooling. As Andy Revkin astutely put it in his blog: "The formula holds: more CO2 = warming world = less ice + higher seas + lots of changing climate patterns."
Image from dsearls
"Positive bias as a result of instrumental errors"
The scientists blamed the discrepancies on a "positive bias as a result of instrumental errors" in a measuring device, the bathythermograph, used by submarines and other vessels. In the past, researchers have used it to find particular thermoclines, the depth at which cold and warm water ocean layers meet; the problem was that they had been comparing the readings taken year after year. As Revkin explains, the bathythermograph is only able to take single snapshots of water temperature and thus wasn't the appropriate device to use for these measurements.
After reviewing the millions of readings taken over the last 4 decades and correcting for the systematic biases, the scientists found previous estimates had significantly lowballed the extent of ocean thermal expansion and sea level rises. The study also helped reinforce scientists' confidence in the ability of climate models to deliver results that matched past observations, Peter Gleckler, a climate scientist with the Lawrence Livermore National Laboratory explained.
Biopact has more background on the study and some nice figures that show the steady rise in sea levels over the past 4 decades.
More about Sea Level Rises
::See For Yourself: Interactive Sea Level Rise Explorer
::Sea Level Rise this Century Higher than Previously Thought
::Rising Seas, Falling Villas
::Indian Ocean Shows Signs of Global Warming
::Antarctic Icebergs Creating New Ecosystems