Sea level rise or seabed subsidence?

[marchesarosa]

How much of the hyped sea-level rise is actually susidence and normal coastal erosion?

I have been looking at sea-level recently and have found that most of the great river deltas of the world are suffering subsidence because of the reduction in silt that used to be delivered to the deltas. The usual cause? Upstream hydrological engineering projects i.e dams and ground water extraction.

These affect the Mississippi, the Nile, the Ganges, Brahmaputra and Meghna in Bangladesh and the Po in Italy (Venice), the Yangzte in China. I’ll get back as I discover more.

These effects are hyped by AGWers as the predicted sea level rise that is the signal of man’s influence on the climate. But there is more to the story than that.

Indeed it is EXPERIENCED as sea level rise locally but it’s actually more the lowering of the land than the rising of the ocean.




P.S. the Yangtze Kiang was also called "China's Sorrow", long before human agency was mooted in environmental changes.

[marchesarosa]

Jan 11 2010


Sea-level theory cuts no ice
By Jonathan Leake, Australian

CLIMATE science faces a major new controversy after Britain’s Met Office denounced research from the Copenhagen summit that suggested global warming could raise sea levels by more than 1.8m by 2100.

The studies, led by Stefan Rahmstorf, professor of ocean physics at the Potsdam Institute for Climate Impact Research in Germany, have caused growing concern among other experts. They say his methods are flawed and that the real increase in sea levels by 2100 is likely to be far lower than he predicts.

Jason Lowe, a leading Met Office climate researcher, said: “We think such a big rise by 2100 is actually incredibly unlikely. The mathematical approach used to calculate the rise is completely unsatisfactory.”

The new controversy dates back to January 2007 when Science magazine published a research paper by Professor Rahmstorf linking the 17cm rise in sea levels from 1881 to 2001 with a 0.6C rise in global temperature over the same period.

Professor Rahmstorf then parted company from colleagues by extrapolating the findings to 2100. Based on the 17cm increase that occurred from 1881 to 2001, Professor Rahmstorf calculated that a predicted 5C increase in global temperature would raise sea levels by up to 188cm.

Critic Simon Holgate, a sea-level expert at the Proudman Oceanographic Laboratory, Merseyside, has written to Science magazine, attacking Professor Rahmstorf’s work as “simplistic”.

“Rahmstorf’s real skill seems to be in publishing extreme papers just before big conferences like Copenhagen, when they are guaranteed attention,” Dr Holgate said.

Most of the 1881-2001 sea-level rise came from melting glaciers that will be gone by 2050, leaving the Antarctic and Greenland ice sheets as contributors. But contributions of these sheets to date has been negligible and researchers say there is no evidence to show that will change in the way Professor Rahmstorf suggests.

Professor Rahmstorf said he accepted many of the criticisms. “I hope my critics are right because a rise of the kind my work predicts would be catastrophic,” he said.




Can a split be appearing in the massive global climatechange consensus, I wonder, between the extremists and the moderates of AGW?