World's Sea Levels Rising At Accelerating Rate
James Randerson and Ian Sample
The researchers say the study puts to bed claims that climate scientists have exaggerated the consequences of global warming. And because the study shows that sea level is responding even faster than expected, the work suggests governments have even less time to act in order to combat climate change.
The report was published in the journal Science ahead of the UN Intergovernmental Panel on Climate Change's (IPCC) report, published today, which brings together the last three years of research on global warming. The heavily trailed tome will say that it is "highly unlikely (less than 5%)" that observed warming and ice loss are due to natural factors.
"The main message is addressed to people who have claimed in the past that the IPCC exaggerates climate change," said David Parker at the Hadley Centre for Climate Change Research in Exeter who was part of the sea level research team.
"What we're saying is that the real climate system is changing as fast or even faster than expected by past IPCCs."
The research shows that between 1993 and 2006, sea levels rose by 3.3mm a year on average, while the 2001 IPCC report had predicted an annual rise of less than 2mm.
This is right at the upper limit of the uncertainty in the IPCC's predictions due to very little data on how ice on land will respond to warming and how fast it will melt. If the climate follows this upper sea level prediction we will experience an 88cm rise in sea levels by the end of the century - much higher than the 14 - 43cm rise predicted under the IPCC's most likely climate scenario.
A rise of close to 1m would threaten huge areas of low lying coastal land, as well as major cities such as London, New York and Tokyo.
The team also looked at how good the IPCC's predictions of CO2 levels and temperature were. While the prediction for CO2 levels was nearly bang on, the temperature increase was slightly higher than the most likely scenario.
Since 1990, global climate has warmed by 0.33 C on average. In the last century, the planet experienced a warming of around 0.7 C. The researchers caution though that 16 years of data is a short time in climate terms so they cannot rule out natural variability.
http://environment.guardian.co.uk/climatechange/story/0,,2004718,00.html