Re: Green Hydrogen Production: A Work in Progress

Climate Model Predicts Greater Melting, Submerged Cities



Image: COURTESY OF AAAS

Over the past 30 years, temperatures in the Arctic have been creeping
up, rising half a degree Celsius with attendant increases in glacial
melting and decreases in sea ice. Experts predict that at current
levels of greenhouse gases--carbon dioxide alone is at 375 parts per
million--the earth may warm by as much as five degrees Celsius,
matching conditions roughly 130,000 years ago. Now a refined climate
model is predicting, among other things, sea level rises of as much as
20 feet, according to research results published today in the journal
Science.
Modeler Bette Otto-Bliesner of the National Center for Atmospheric
Research in Boulder and paleoclimatologist Jonathan Overpeck of the
University of Arizona matched results from the Community Climate System
Model and climate records preserved in ice cores, exposed coral reefs,
fossilized pollen and the chemical makeup of shells to determine the
accuracy of the computer simulation. Roughly 130,000 the Arctic enjoyed
higher levels of solar radiation, leading to increased warming in the
summer and the retreat of glaciers worldwide. The model correctly
predicted the extent of the resulting Arctic ice melt, enough to raise
sea levels by roughly nine feet.






"Getting the past climate change correct in these models gives us more
confidence in their ability to predict future climate change,"
Otto-Bliesner says. "These ice sheets have melted before and sea levels
rose. The warmth needed isn't that much above present conditions."
But sea levels rose as much as 20 feet 130,000 years ago and Overpeck
speculates that may have been the result of additional melting in
Antarctica. After all, the ice there is not all landlocked; some rests
in the ocean and a little warming in sea temperatures could melt it or
pry it loose. And this time around, the warming is global, rather than
concentrated in the Arctic. "In the Antarctic, all you have to do is
break up the ice *** and float it away and that would raise sea
level," he says. "It's just like throwing a bunch of ice cubes into a
full glass of water and watching the water spill over the top."



Image: COURTESY OF JEREMY WEISS AND JONATHAN OVERPECK, THE UNIVERSITY
OF ARIZONA

Such a sea level rise would permanently inundate low-lying lands like
New Orleans, southern Florida, Bangladesh and the Netherlands. Already
sea level rise has increased to an inch per decade, thanks to melting
ice and warm water expansion, according to Overpeck. And evidence that
the Arctic is exponentially warming continues to accumulate. Indeed, in
another paper in the same issue of Science, Goran Ekstrom of Harvard
University reported a marked increase in so-called glacial earthquakes
(seismic events recorded throughout the world when Greenland's glaciers
slip past rock) since 2002. In fact, last year alone saw twice as many
quakes as in previous years, with most of that increase coming during
the summer months.
"We need to start serious measures to reduce greenhouse gases within
the next decade," Overpeck says. "If we don't do something soon, we're
committed to [13 to 20 feet] of sea level rise in the future." --David
Biello




http://www.scientificamerican.com/article.cfm?chanID=sa012&articleID=0007FA05-10BC-1423-90BC83414B7F0000

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