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View Full Version : Experts offer scaled-back sea level rise forecast


Renegade
09-05-2008, 07:02 AM
Thu Sep 4, 2008 5:10pm EDT


By Will Dunham

WASHINGTON (Reuters) - Worldwide sea levels may rise by about 2.6 to 6.6 feet by 2100 thanks to global warming, but dire predictions of larger increases seem unrealistic, U.S. scientists said on Thursday.

They examined scenarios for loss of ice from Greenland, Antarctica and the world's smaller glaciers and ice caps into the world's oceans, as well as ocean expansion simply due to rising water temperatures.

Their calculations yielded estimates for global sea level increases by the end of the century that are lower than many existing projections, but alarming nonetheless.

"If you look at the actual mechanics of how glaciers work, there doesn't seem to be a realistic way that we know about to get more than about 2 meters of sea level rise in the next century," Tad Pfeffer of the University of Colorado's Institute of Arctic and Alpine Research, whose study was published in the journal Science, said in a telephone interview.

"The real unknown right now is what we call the dynamic effect of ice not melting but just being pushed straight into the ocean," Pfeffer added, referring to pieces of ice breaking off from huge masses of ice such as glaciers and ice sheets and floating in the sea.

Scientists have been working to predict the global effects in coming decades of rising temperatures attributed to human activities that have fueled a "greenhouse effect" on Earth.

Rising sea levels are one of the threats. Scientists have debated how much the seas will rise this century, and some have predicted increases far higher than what this study predicts.

Previous projections of 20 feet or more of sea level rise by the end of the century do not seem to be supported by solid evidence, Pfeffer said.

Pfeffer and scientists at the University of Montana and the University of California at San Diego came up with an estimate of a sea level rise of about 2.6 feet. But their calculations using a "realistic worst-case scenario" produced a predicted rise of 6.6 feet, Pfeffer said.

Even an increase in that range would likely cause major problems in low-lying coastal areas that are home to untold millions of people, he said.

For example, regions of Bangladesh, China and elsewhere could be devastated, while coastal cities such as New Orleans, Amsterdam or Venice could be swamped.

"These places throughout the world where Third World populations live within a meter of sea level and grow a lot of their food within a meter of sea level, they're the ones who are really going to be hurt," Pfeffer said.

(Editing by Julie Steenhuysen and Todd Eastham)
http://www.reuters.com/article/scienceNews/idUSN0442173820080904?sp=true

rb.
09-05-2008, 07:09 AM
Don't look for Al Gore to adjust his propaganda "facts" anytime soon. Sure is a good thing we didn't do anything drastic based on this stuff, eh? :re:

Kassy
09-06-2008, 03:04 AM
Don't look for Al Gore to adjust his propaganda "facts" anytime soon. Sure is a good thing we didn't do anything drastic based on this stuff, eh? :re:

You underestimate how bad even a 1 meter rise would be for many areas.

This PDF gives estimates for population effected by different rises of sea level. One meter would effect nearly 108 million people.
See table 1:
http://www2.ku.edu/~geography/Docs/RowleyEtAl_Risk.pdf

Oric
09-06-2008, 05:38 PM
1 meter is high enough to cause panic

rb.
09-06-2008, 08:22 PM
And would these not be areas that already have to deal with flooding on a regular basis, due to typhoons, etc.? When humans don't like what's going on where they live, they move. If they're smart. Doesn't matter if they have to walk out of wars, water, new desert, or wind-swept debris, they leave. Or perish. I don't mean to sound callous, but it's survival of the fittest, just like any other animal.

BirdGuano
09-06-2008, 08:26 PM
And would these not be areas that already have to deal with flooding on a regular basis, due to typhoons, etc.? When humans don't like what's going on where they live, they move. If they're smart. Doesn't matter if they have to walk out of wars, water, new desert, or wind-swept debris, they leave. Or perish. I don't mean to sound callous, but it's survival of the fittest, just like any other animal.

Unless you are Al Gore and then you tax those people with carbon credit schemes.

Fiddlerdave
09-12-2008, 05:30 PM
And would these not be areas that already have to deal with flooding on a regular basis, due to typhoons, etc.? When humans don't like what's going on where they live, they move. If they're smart. Doesn't matter if they have to walk out of wars, water, new desert, or wind-swept debris, they leave. Or perish. I don't mean to sound callous, but it's survival of the fittest, just like any other animal.The infastructure costs for ports and other low lying with levees, etc., even to areas in countries like the USA, will be trillions. How full is our piggy-bank to pay for it?

Flint
09-14-2008, 10:45 PM
The infastructure costs for ports and other low lying with levees, etc., even to areas in countries like the USA, will be trillions. How full is our piggy-bank to pay for it?This question misses the mark a little bit. We're talking about a time 90 years from now. By that time, it's already anticipated that nearly all of our infrastructure must be repaired or replaced - all our dams, all our roads, most of our buildings, etc.

Combine this with the nearly artificial nature of these calculations. IF our models are correct (the baseline for our models isn't very long, and the the longest elements of that baseline aren't very comprehensive), the predictive errors are necessarily very large. It's not so hard to specify the maximum rise in ocean levels, but predicting how much ice will melt over the next 90 years requires so hugely many assumptions as to be nearly meaningless.

What feedback effects are in operation? What changes in albedo will be positive or negative influences? What decisions will nations make? Will running out of oil (flat guaranteed within 90 years) change our carbon footprint? Will weather changes alter our population, or our geographic distributions? Will a bird flu epidemic decimate the human population? Will space technologies change energy usage patterns? The list of relevant imponderables is certainly beyond the scope of any rational predictive model.

But most relevant changes will be slow. If the oceans were 1-2 meters higher tomorrow, the shock would be catastrophic. A rise in sea level of 1-2 cm a year would put us in a manageable "putting out fires" mode.