Tag: sea level rise

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Climate scientists say they have solved riddle of rising sea

The answer lies in water that is extracted from underground aquifers Massive extraction of groundwater can resolve a puzzle over a rise in sea levels in past decades, scientists in Japan said on Sunday.Global sea levels rose by an average of 1.8 millimetres (0.07 inches) per year from 1961-2003, according to data from tide gauges.But the big question is how much of this can be pinned to global warming.In its landmark 2007 report, the UN's Nobel-winning Intergovernmental Panel on Climate Change (IPCC) ascribed 1.1mm (0.04 inches) per year to thermal expansion of the oceans -- water expands when it is heated -- and to meltwater from glaciers, icecaps and the Greenland and Antarctica icecaps.That left 0.7mm (0.03 inches) per year unaccounted for, a mystery that left many scientists wondering if the data were correct or if there were some source that had eluded everyone.In a study published in the journal Nature Geoscience, a team led by Yadu Pokhrel of the University of Tokyo say the answer lies in water that is extracted from underground aquifers, rivers and lakes for human development but is never replenished.The water eventually makes it to the ocean through rivers and evaporation in the soil, they ...

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Increasing speed of Greenland glaciers gives new insight for rising sea level

30 percent speedup in 10 years Changes in the speed that ice travels in more than 200 outlet glaciers indicates that Greenland's contribution to rising sea level in the 21st century might be significantly less than the upper limits some scientists thought possible, a new study shows."So far, on average we're seeing about a 30 percent speedup in 10 years," said Twila Moon, a University of Washington doctoral student in Earth and space sciences and lead author of a paper documenting the observations published May 4 in Science.The faster the glaciers move, the more ice and meltwater they release into the ocean. In a previous study, scientists trying to understand the contribution of melting ice to rising sea level in a warming world considered a scenario in which the Greenland glaciers would double their velocity between 2000 and 2010 and then stabilize at the higher speed, and another scenario in which the speeds would increase tenfold and then stabilize.At the lower rate, Greenland ice would contribute about four inches to rising sea level by 2100 and at the higher rate the contribution would be nearly 19 inches by the end of this century. But the researchers who conducted that study ...

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Geophysicists employ novel method to identify sources of global sea level rise

New method to distinguish sea-level fingerprints in historical records of sea levels As the Earth's climate warms, a melting ice sheet produces a distinct and highly non-uniform pattern of sea-level change, with sea level falling close to the melting ice sheet and rising progressively farther away. The pattern for each ice sheet is unique and is known as its sea level fingerprint.Now, a group of geophysicists from the University of Toronto, Harvard and Rutgers Universities have found a way to identify the sea level fingerprint left by a particular ice sheet, and possibly enable a more precise estimate of its impact on global sea levels."Our findings provide a new method to distinguish sea-level fingerprints in historical records of sea levels, from other processes such as ocean waves, tides, changes in ocean circulation, and thermal expansion of the ocean," says Carling Hay, a Ph D candidate in the Department of Physics at the University of Toronto and lead author of a study published in Proceedings of the National Academy of Sciences (PNAS)."It may indeed allow us to estimate the contributions of individual ice sheets to rising global sea levels."Scientists around the world are trying to estimate both the current rate of ...

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Kiribati Global Warming Fears

Entire Nation May Move To Fiji Fearing that climate change could wipe out their entire Pacific archipelago, the leaders of Kiribati are considering an unusual backup plan: moving the populace to Fiji.Kiribati President Anote Tong told The Associated Press on Friday that his Cabinet this week endorsed a plan to buy nearly 6,000 acres on Fiji's main island, Viti Levu. He said the fertile land, being sold by a church group for about $9.6 million, could be insurance for Kiribati's entire population of 103,000, though he hopes it will never be necessary for everyone to leave."We would hope not to put everyone on one piece of land, but if it became absolutely necessary, yes, we could do it," Tong said. "It wouldn't be for me, personally, but would apply more to a younger generation. For them, moving won't be a matter of choice. It's basically going to be a matter of survival."Kiribati, which straddles the equator near the international date line, has found itself at the leading edge of the debate on climate change because many of its atolls rise just a few feet above sea level.Tong said some villages have already moved and there have been increasing instances of ...

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Warming Raising Sea Level

Says New Climate Change Report Ice-age geologic records suggest Earth's climate will warm faster than expected, pushing the global sea level perhaps more than 3 feet higher within this century, a panel of scientists warned Tuesday.Speaking at the American Geophysical Union annual meeting here, federal and academic scientists said they reviewed ice core measures spanning more than 500,000 years of Ice Ages and subsequent warming periods to warn that ice sheets in the past had quickly melted once temperatures reached tipping points."It's like the ice on your windshield suddenly starting to melt all at once," says Eelco Rohling of the United Kingdom's University of Southampton. "The ice takes a little kicking and then it melts."Sea-level rise has long been a point of contention among climate scientists, who overwhelmingly agree that humanity adding greenhouse gases such as carbon dioxide to the atmosphere has raised global average temperatures about 1.4 degrees Fahrenheit worldwide in the last century, according to a 2010 National Academy of Sciences report.Exactly how much hotter it will get by 2100 if humanity doubles the amount of atmospheric carbon dioxide - projected to happen by 2060 at present rates by the 2007 Intergovernmental Panel on Climate Change (IPCC) - ...

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Arctic Sea Ice Decline Greatest, Longest In 1,450 Years

more in the last half-century than it has any time over the last 1,450 years.! Research published in a top scientific journal says Arctic sea ice has declined more in the last half-century than it has any time over the last 1,450 years.The study, which gives the most detailed picture ever of the northern oceans over the previous millennium-and-a-half, also concludes the current decline has already lasted longer than any previous one in that period."When we look at our reconstruction, we can see that the decline that has occurred in the last 50 years or so seems to be unprecedented for the last 1,450 years," Christian Zdanowicz of the Geological Survey of Canada said Wednesday."It's difficult not to come up with the conclusion that greenhouse gases must have something to do with this," added Zdanowicz, one of the co-authors of the report in Nature."We cannot account for this decline by processes that are 'natural.'"Climate change is thought to be occurring faster in the Arctic than anywhere else on Earth and sea ice is considered one of the main indicators. The ice is crucial in northern ecosystems because it provides habitat for everything from plankton to polar bears.Its gradual disappearance is ...

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Rhine and Danube shipping troubled by lower water

Some vessels sailing under half full A further fall in water levels this week is hindering freight shipping on the Rhine and Danube rivers in Germany and many vessels are sailing only 50 to 20 percent full, traders said on Wednesday.Rhine water levels have fallen because of dry weather in Germany and Switzerland, continuing a period of shallowness which started in late October.Water levels are so low that the maximum length of vessel permitted to sail in some southern sections of the river has been reduced to 116.50 metres from 135 metres normally, a spokeswoman for the German inland navigation agency said."Vessels over this length have to apply for a permit and undertake a test sailing," she said.The river is too shallow to allow vessels to sail with full loads on the river from Duisburg in the north to Switzerland, traders said.Water is so low on the Rhine from Cologne to southern regions around Koblenz that vessel owners have a contractual right to refuse to sail if they think their vessels will be damaged.Low water means vessels are unable to load to full capacity and surcharges are added to freight rates, increasing costs for cargo owners.More vessels are also required ...

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Sea level rise less from Greenland and more from Antarctica

Than expected during last interglacial, according to new results During the last prolonged warm spell on Earth, the oceans were at least four meters - and possibly as much as 6.5 meters, or about 20 feet - higher than they are now.Where did all that extra water come from? Mainly from melting ice sheets on Greenland and Antarctica, and many scientists, including University of Wisconsin-Madison geoscience assistant professor Anders Carlson, have expected that Greenland was the main culprit.But Carlson's new results, published July 29 in Science, are challenging that assertion, revealing surprising patterns of melting during the last interglacial period that suggest that Greenland's ice may be more stable - and Antarctica's less stable - than many thought."The Greenland Ice Sheet is melting faster and faster," says Carlson, who is also a member of the Center for Climatic Research in the Nelson Institute for Environmental Studies. But despite clear observations of that fact, estimates of just how much the ice will melt and contribute to sea level rise by the end of this century are highly varied, ranging from a few centimeters to meters."There's a clear need to understand how it has behaved in the past, and how it has ...

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Sea levels will rise by up to a metre within a century due to global warming

Global average sea-level rise in 2100 will be in range of 0.5 to 1.0 m Sea levels are set to rise by up to a metre within a century due to global warming, a new Australian report said on Monday, as it warned this could make "once-a-century" coastal flooding much more common.The government's first Climate Commission report said the evidence that the Earth's surface was warming rapidly was beyond doubt.Drawn from the most up-to-date climate science from around the world, the report said greenhouse gas emissions created by human industry was the likely culprit behind rising temperatures, warming oceans, and rising sea levels.Its author Will Steffen said while the report had been reviewed by climate scientists from Australian science body the CSIRO, the Bureau of Meteorology and academics, some judgments, including on sea levels, were his own."I expect the magnitude of global average sea-level rise in 2100 compared to 1990 to be in the range of 0.5 to 1.0 metre," Steffen said in his preface to "The Critical Decade".He said while this assessment was higher than that of the Intergovernmental Panel for Climate Change in 2007, which was under 0.8m, it was not inconsistent with the UN body which had ...

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