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.
After 30 years working in mountain regions, Jack Ives argues that the world's elevated habitats are essential
Long-range tracking technology will help researchers understand bee behavior.
Rising temperatures in the coming years may result in less tasty vegetables, meat and dairy products, report says
Americans concerns near record lows
In South Florida, the world's two most destructive termite species could be mating because of climate change. Researchers say if the hybrids colonize, they could pose an even greater economic threat.
War, pestilence, even climate change, are trifles by comparison. Destroy the soil and we all starve
Director of the charitable trust, Jeremy Farrar, says retaining fossil fuel shares gives more influence over such companies – but they would not rule out divesting in the future, should engagement prove ineffective
ROME (Thomson Reuters Foundation) - Scientists have bred 30 new varieties of "heat-beating" beans designed to provide protein for the world's poor in the face of global warming, researchers announced on Wednesday.
Climate change-related rising sea levels are expected to intensify erosion; "It's half of our economy"
Animal rights groups hope an appeals court will help free the orca Lolita from a Miami aquarium where it has lived since 1970