Ocean Temperatures And Sea Level Increases 50 Percent Higher Than Previously Estimated
Pastor Dale Morgan
Ocean Temperatures And Sea Level Increases 50 Percent Higher Than
Previously Estimated*
by Staff Writers
Livermore CA (SPX) Jun 20, 2008
New research suggests that ocean temperature and associated sea level
increases between 1961 and 2003 were 50 percent larger than estimated in
the 2007 Intergovernmental Panel on Climate Change report.
The results are reported in the June 19 edition of the journal Nature.
An international team of researchers, including Lawrence Livermore
National Laboratory climate scientist Peter Gleckler, compared climate
models with improved observations that show sea levels rose by 1.5
millimeters per year in the period from 1961-2003. That equates to an
approximately 2˝-inch increase in ocean levels in a 42-year span.
The ocean warming and thermal expansion rates are more than 50 percent
larger than previous estimates for the upper 300 meters of oceans.
The research corrected for small but systematic biases recently
discovered in the global ocean observing system, and uses statistical
techniques that "infill" information in data-sparse regions. The results
increase scientists' confidence in ocean observations and further
demonstrate that climate models simulate ocean temperature variability
more realistically than previously thought.
"This is important for the climate modeling community because it
demonstrates that the climate models used for assessing sea-level rise
and ocean warming tie in closely with the observed results," Gleckler said.
Climate model data were analyzed from 13 different modeling groups. All
model data were obtained from the WCRP CMIP3 multi-model dataset
archived at the LLNL's Program for Climate Model Diagnosis and
Intercomparison (PCMDI).
Although observations and models confirm that recent warming is greatest
in the upper ocean, there are widespread observations of warming deeper
than 700 meters.
Results were compared with recent estimates of other contributions to
sea-level rise including glaciers, ice caps, Greenland and Antarctic ice
sheets, and thermal expansion changes in the deep ocean. When these
independent lines of evidence are examined collectively, the story is
more consistent than found in earlier studies.
The oceans store more than 90 percent of the heat in the Earth's climate
system and act as a temporary buffer against the effects of climate
change. The ocean warming and thermal expansion rates are 50 percent
larger than previous estimates for the upper 700 meters of oceans, and
greater than that for the upper 300 meters.
"This is just the tip of the iceberg, so to speak," Gleckler said. "Our
ability to quantify structural uncertainties in observationally based
estimates is critically important. This study represents important
progress."
The team involved researchers from the Centre for Australian Weather and
Climate Research (CSIRO), the Antarctic Climate and Ecosystems
Cooperative Research Centre and LLNL.
Founded in 1952, Lawrence Livermore National Laboratory is a national
security laboratory, with a mission to ensure national security and
apply science and technology to the important issues of our time.
Lawrence Livermore National Laboratory is managed by Lawrence Livermore
National Security, LLC for the U.S. Department of Energy's National
Nuclear Security Administration.