Another Stephan Rahmstorf sea level scare

From the Potsdam Institute for Climate Impact Research (PIK)  another Stephan Rahmstorf scare projection, so important they couldn’t even wait for it to be put on the NCC website before sending off this press release to Eurekalert (see weblink at end of story which is DOA as of 10PM PST 6/24).

Significant sea-level rise in a 2-degree warming world

Sea levels around the world can be expected to rise by several meters in coming centuries, if global warming carries on

The study is the first to give a comprehensive projection for this long perspective, based on observed sea-level rise over the past millennium, as well as on scenarios for future greenhouse-gas emissions.

“Sea-level rise is a hard to quantify, yet critical risk of climate change,” says Michiel Schaeffer of Climate Analytics and Wageningen University, lead author of the study. “Due to the long time it takes for the world’s ice and water masses to react to global warming, our emissions today determine sea levels for centuries to come.”

Limiting global warming could considerably reduce sea-level rise

While the findings suggest that even at relatively low levels of global warming the world will have to face significant sea-level rise, the study also demonstrates the benefits of reducing greenhouse-gas emissions. Limiting global warming to below 1.5 degrees Celsius and subsequent temperature reductions could halve sea-level rise by 2300, compared to a 2-degree scenario. If temperatures are allowed to rise by 3 degrees, the expected sea-level rise could range between 2 and 5 metres, with the best estimate being at 3.5 metres.

The potential impacts are significant. “As an example, for New York City it has been shown that one metre of sea level rise could raise the frequency of severe flooding from once per century to once every three years,” says Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research, co-author of the study. Also, low lying deltaic countries like Bangladesh and many small island states are likely to be severely affected.

Sea-level rise rate defines the time for adaptation

The scientists further assessed the rate of sea-level rise. The warmer the climate gets, the faster the sea level climbs. “Coastal communities have less time to adapt if sea-levels rise faster,” Rahmstorf says.

“In our projections, a constant level of 2-degree warming will sustain rates of sea-level rise twice as high as observed today, until well after 2300,” adds Schaeffer, “but much deeper emission reductions seem able to achieve a strong slow-down, or even a stabilization of sea level over that time frame.”

Building on data from the past

Previous multi-century projections of sea-level rise reviewed by the Intergovernmental Panel on Climate Change (IPCC) were limited to the rise caused by thermal expansion of the ocean water as it heats up, which the IPCC found could reach up to a metre by 2300. However, this estimate did not include the potentially larger effect of melting ice, and research exploring this effect has considerably advanced in the last few years. The new study is using a complementary approach, called semi-empirical, that is based on using the connection between observed temperature and sea level during past centuries in order to estimate sea-level rise for scenarios of future global warming.

“Of course it remains open how far the close link between temperature and global sea level found for the past will carry on into the future,” says Rahmstorf. “Despite the uncertainty we still have about future sea level, from a risk perspective our approach provides at least plausible, and relevant, estimates.”

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Article: Schaeffer, M., Hare, W., Rahmstorf, S., Vermeer, M. (2012): Long-term sea-level rise implied by 1.5° C and 2° C warming levels. Nature Climate Change [doi:10.1038/NCLIMATE158] (Advance Online Publication)

Weblink to the article when it is published on June 24th: http://dx.doi.org/10.1038/NCLIMATE158

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UPDATE: The link above is as published at Eurekalert. The bolding of “when” is mine. Harold W points out in comments:

Correct link to the article is http://dx.doi.org/10.1038/NCLIMATE1584 [Published link lacked the final digit], or alternatively http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1584.html

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D. J. Hawkins
June 26, 2012 5:49 pm

KenB says:
June 25, 2012 at 11:45 pm
cui bono says:
June 25, 2012 at 2:56 am

In 1980 Sweden’s Department of Forestry wrote a letter to the Swedish Navy, informing the Navy that its lumber was ready. One hundred fifty years earlier, in 1829 Swedish planners predicted that a shortage of oak timber suitable for building warships would arise by the year 1990. So they instructed the foresters to be proactive, and the foresters planted a new oak forest on a government-owned island, knowing that it takes ship-quality timber at least 150 years to mature. In their view, I’m sure, they felt that they had barely forestalled certain disaster…

There is a similar story I’ve heard regarding Oxford or Cambridge. The oak beams in one of the great halls were worm-ridden to the point of structural failure. The problem being that as far as they knew, no oaks of sufficient height and girth remained in England to replace them. Then the university’s forester informed them that the builders had been aware of the need 300 years hence and planted a grove of oaks in anticipation. Problem solved.

David G
June 26, 2012 7:37 pm

Anthony, I agree with those who say we need an expert treatment of sea level issues on WUWT; the media is full of BS that isn’t being challenged adequately.

Spector
June 27, 2012 1:12 am

Time Capsule:
Here is a link to a news report that came out a few months before the Copenhagen Conference failed to produce an international accord to control greenhouse gas emissions and before the Climategate Emails were released:
Two meter sea level rise unstoppable: experts
“By Gerard Wynn
OXFORD, England | Wed Sep 30, 2009 9:12am EDT
(Reuters) – A rise of at least two meters in the world’s sea levels is now almost unstoppable, experts told a climate conference at Oxford University on Tuesday.”
“The crux of the sea level issue is that it starts very slowly but once it gets going it is practically unstoppable,” said Stefan Rahmstorf, a scientist at Germany’s Potsdam Institute and a widely recognized sea level expert.
“There is no way I can see to stop this rise, even if we have gone to zero emissions.”

http://www.reuters.com/article/2009/09/30/us-climate-seas-idUSTRE58S4L420090930