Prehistoric Greenland Ice Melt Led to 20-Foot Sea Rise
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The effects of global warming are frequently projected decades into the future, but two recent reports -- one from theU.S. Global Change Research Program
and the otherfrom the U.N.
-- put into sharp focus visible consequences of our warming planet. An increase in temperature, extreme weather, loss of ice and rising sea level are just a few of changes we can measure right now. Let's take a look at some of the most concerning trends.BLOG: War Of The Words: Climate Change Or Global Warming?
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Sea level around the world has increased by about 8 inches since 1880, reports the 2014 National Climate Assessment, which projects a 1 to 4 foot rise by the end of the century.PHOTOS: Craziest Environmental Ideas (That Could Work)
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The probability of a Sandy-like storm deluging New York, New Jersey and other parts of the East Coast has nearly doubled compared to 1950, according to the American Meteorological Society. Even weaker storms will be more damaging now than they were 10 years ago because of rising sea levels. Superstorm Sandy cost the nation $65 billion, according to the 2014 National Climate Assessment, and 2012's Hurricane Isaac cost $2.3 billion.
The global sea level rises along with the temperature for two major reasons. For one, heat causes water to expand, which causes the existing water to take up more space and encroach on the coast. At the same time, ice at the poles and in glaciers melts and increases the amount of water in the oceans.PHOTOS: Melting Glaciers
Across the United States, heavy downpours are on the rise, especially in the Northeast and Midwest. Increases in extreme precipitation are expected for all U.S. regions, reports the 2014 National Climate Assessment.NEWS: Shrinking Greenland Glacier Smashes Speed Record
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The most recent IPCC report states with "very high confidence" that current climate-related extremes like heat waves, droughts, floods, cyclones and wildfires are showing that countries around the world, at all development levels, are significantly unprepared. The American Meteorological Society estimates that approximately 35 percent of the extreme heat in the eastern United States between March and May 2012 resulted from human activities' effects on climate. The AMS warned that deadly heat waves will become four times more likely in the north-central and northeastern United States as the planet continues to warm.NASA: Global Warming Goes On
More than 400,000 years ago, the Greenland ice sheet collapsed, causing worldwide sea levels to rise between 13 and 20 feet, reports a new study.
Unlike current global warming due to the buildup of atmospheric CO2, the ice sheet melted during this long warm period between ice ages because of changes to the Earth's orbit around the sun.
“The climate 400,000 years ago was not that much different than what we see today, or at least what is predicted for the end of the century,” Anders Carlson, an associate professor at Oregon State University and co-author on the study, said in a press release. “The forcing was different, but what is important is that the region crossed the threshold allowing the southern portion of the ice sheet to all but disappear."
Other studies show the sea level rise during that time could have been greater than 40 feet, the researchers reported. The ice sheet melted beyond Greenland's southern edges, but the melting didn't reach the center, which hasn't been without ice for 1 million years, Carlson said.
The researchers studied glacial stream sediment cores taken off of the coast of Greenland.
“Each terrain has a distinct fingerprint,” Carlson said. “They also have different tectonic histories and so changes between the terrains allow us to predict how old the sediments are, as well as where they came from. The sediments are only deposited when there is significant ice to erode the terrain. The absence of terrestrial deposits in the sediment suggests the absence of ice.
“Not only can we estimate how much ice there was,” he said, “but the isotopic signature can tell us where ice was present, or from where it was missing. This may give us a better sense of what may happen in the future as temperatures continue rising."
The study was funded by the National Science Foundation and published this week in the journal Nature.