A new study led by Lawrence Livermore National Laboratory strengthens evidence that human-caused climate change is warming the oceans, more than 10 years after a pair of Scripps Institution of Oceanography, UC San Diego researchers made that initial finding.
Scripps climate scientists Tim Barnett and David Pierce also contributed to the new study, in which researchers used the latest generation of computer models to analyze an average 0.1-degree C (0.18-degree F) temperature rise in the top 700 meters (2,300 feet) of the oceans since 1960. That warming trend had been identified a year earlier by researcher Sydney Levitus and colleagues at NOAA’s National Oceanographic Data Center. Now, as in Barnett and Pierce’s original analysis, the models found that the warming trend could only be explained if the surge in global greenhouse gas concentrations mostly created by fossil fuel use were considered as a factor. The trend did not correlate to the effects of natural phenomena such as solar radiation and volcanic activity.
The difference is that while Barnett and Pierce relied on the output of two computer models for their original study released in 2001, the new study reports consensus among 13 computer models. Four of the estimates came from models supplying data to the next report of the Intergovernmental Panel on Climate Change (IPCC), which is scheduled to be released in stages starting in 2013. The authors of the last IPCC report, issued in 2007, shared the Nobel Peace Prize with Al Gore that year.
“It puts the human causality of ocean warming on an even stronger footing than it was before,” said Barnett.
Pierce said the conclusion of the new study does not differ from that made in 2001 but the confirmation was important for several reasons. Some of the historical temperature observations which he and Barnett relied upon in 2001 were later shown to be biased; corrected data has been used in the new analysis.
“So the subject needed to be revisited for that if nothing else,” Pierce said.
Peter Glecker, a climate scientist at Lawrence Livermore, led the study. Other co-authors are from the Antarctic and Climate Ecosystems Cooperative Research Centre in Hobart, Australia, CSIRO Marine and Atmospheric Research in Hobart, the Indian Institute of Technology in Delhi, India, NOAA, and the Meteorological Research Institute in Tsukuba, Japan.
– Robert Monroe