RollingThunder
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One of the latest studies shows sea levels rising even faster.
Rising Sea Level Tied to Faster Melt
The Wall Street Journal
June 2, 2013
(excerpts)
Accelerated melting of polar ice sheets and mountain glaciers was the driving factor behind a rise in the global sea level of 16.8 millimeters, or about two-thirds of an inch, between 2005 and 2011, according to a study published Sunday in Nature Geoscience. The findings are consistent with observed longer-term trends, but the study encompasses only a few years of observations, limiting its conclusions, scientists said. The study, funded by the National Science Foundation and the National Aeronautics and Space Administration, does resolve long-standing discrepancies that arose from different methods of measuring sea levels. Scientists want to establish how much of the sea-level change relates to increased melt water, and how much relates to the water expanding as it warms up. Previous calculations indicated that melting might contribute about half of the increase. The latest study concludes that for the period 2005-2011 the contribution was closer to 75%. "There was an increase in the melting rate in Greenland starting in 2005 and that is probably the underlying story why" a larger quantity of melt water has poured into the oceans in recent years, said Clark R. Wilson, geophysicist at the University of Texas at Austin and co-author of the study.
Data from the past two decades suggest a sea level increase of about 3.1 millimeters per year. Shorter-term snapshotssuch as the annual sea level rise of 2.4 millimeters reported in the latest studycan fall slightly below or above that average. Scientists estimate the overall change in sea level by using satellite-mounted radar that measures the height of the sea surface. Alternatively, they can add up two separately calculated componentsthe increased mass of water from melting and other sources, and the increased thermal expansion of the ocean. To measure the thermal expansion of the oceans, data are collected from the Argo Project, which consists of about 3,500 torpedo-like devices that zoom around in the ocean measuring temperature and salinity. Meanwhile, NASA's satellite-based GRACE mission measures the gravity fieldthe varying distribution of massacross the surface of the earth. Water and air move around from month to month, altering the distribution of mass. By measuring these changes, GRACE can get a fix on how much water mass is being added to the oceans each year.
Rising Sea Level Tied to Faster Melt
The Wall Street Journal
June 2, 2013
(excerpts)
Accelerated melting of polar ice sheets and mountain glaciers was the driving factor behind a rise in the global sea level of 16.8 millimeters, or about two-thirds of an inch, between 2005 and 2011, according to a study published Sunday in Nature Geoscience. The findings are consistent with observed longer-term trends, but the study encompasses only a few years of observations, limiting its conclusions, scientists said. The study, funded by the National Science Foundation and the National Aeronautics and Space Administration, does resolve long-standing discrepancies that arose from different methods of measuring sea levels. Scientists want to establish how much of the sea-level change relates to increased melt water, and how much relates to the water expanding as it warms up. Previous calculations indicated that melting might contribute about half of the increase. The latest study concludes that for the period 2005-2011 the contribution was closer to 75%. "There was an increase in the melting rate in Greenland starting in 2005 and that is probably the underlying story why" a larger quantity of melt water has poured into the oceans in recent years, said Clark R. Wilson, geophysicist at the University of Texas at Austin and co-author of the study.
Data from the past two decades suggest a sea level increase of about 3.1 millimeters per year. Shorter-term snapshotssuch as the annual sea level rise of 2.4 millimeters reported in the latest studycan fall slightly below or above that average. Scientists estimate the overall change in sea level by using satellite-mounted radar that measures the height of the sea surface. Alternatively, they can add up two separately calculated componentsthe increased mass of water from melting and other sources, and the increased thermal expansion of the ocean. To measure the thermal expansion of the oceans, data are collected from the Argo Project, which consists of about 3,500 torpedo-like devices that zoom around in the ocean measuring temperature and salinity. Meanwhile, NASA's satellite-based GRACE mission measures the gravity fieldthe varying distribution of massacross the surface of the earth. Water and air move around from month to month, altering the distribution of mass. By measuring these changes, GRACE can get a fix on how much water mass is being added to the oceans each year.