That sea level is rising faster than expected could mean that the Intergovernmental Panel on Climate Change's (IPCC) sea-level rise projections for the future may be biased low as well, their results suggest.
Sea-level rise potentially affects millions of people all around the world in coastal areas as well as megacities like Tokyo.
"Global temperature continues to rise at the rate that was projected in the last two IPCC Reports. This shows again that global warming has not slowed down or is lagging behind the projections," Rahmstorf says. Five global land and ocean temperature series were averaged and compared to IPCC projections by the scientists from Potsdam, the Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS) in France and the US based Tempo Analytics. To allow for a more accurate comparison with projections, the scientists accounted for short-term temperature variations due to El Niño events, solar variability and volcanic eruptions. The results confirm that global warming, which was predicted by scientists in the 1960s and 1970s as a consequence of increasing greenhouse concentrations, continues unabated at a rate of 0.16 °C per decade and follows IPCC projections closely.
Data of sea-level rise provided a different picture though. The oceans are rising 60 per cent faster than the IPCC's latest best estimates, according to the new research. The researchers compared those estimates to satellite data of observed sea-level rise. "Satellites have a much better coverage of the globe than tide gauges and are able to measure much more accurately by using radar waves and their reflection from the sea surface," Anny Cazenave from LEGOS explains. While the IPCC projected sea-level rise to be at a rate of 2 mm per year, satellite data recorded a rate of 3.2 mm per year. The increased rate of sea-level rise is unlikely to be caused by a temporary episode of ice discharge from the ice sheets in Greenland or Antarctica or other internal variabilities in the climate system, according to the study, because it correlates very well with the increase in global temperature.
"In contrast to the physics of global warming itself, sea-level rise is much more complex," Rahmstorf says. "To improve future projections it is very important to keep track of how well past projections match observational data." Rahmstorf stresses that "the new findings highlight that the IPCC is far from being alarmist and in fact in some cases rather underestimates possible risks."
Potsdam Institute for Climate Impact Research (PIK): http://www.pik-potsdam.de
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
There are several captive breeding programs for pandas around the world; but one facility in China hopes to release the endangered animals back into the wild
Researchers argue for a nationwide shift to more premium fuel at the pump
Bird watchers' elusive warbler has shifted its summer habitat to pine plantations
One-child policies and plagues that cut the population won't be enough to fix our ecological problems, models suggest. Only changes in consumption will do that
They were down to only 15 about 50 years ago
Buildup of salts on irrigated land has already degraded an area the size of France and is causing $27.3 billion annually in lost crops
A spectacular electrical storm struck southern Australia last night, causing power outages and setting a house ablaze
Winners of Wildlife Photographer of the Year photography contest as the competition celebrates 50 years
BP has already questioned the results of the new study
The U.S. moves to list them as “threatened”