Indian Ocean Sea Level Rise Threatens Coastal Areas
A new study in Nature Geoscience finds that Indian Ocean sea levels are rising unevenly and threatening residents in some densely populated coastal areas, particularly those along the Bay of Bengal, the Arabian Sea, Sri Lanka, Sumatra, and Java. This image shows the key player in the process, the Indo-Pacific warm pool, in bright orange. This enormous, bathtub-shaped area spans a region of the tropical oceans from the east coast of Africa to the International Date Line in the Pacific. The warm pool has heated by about 1 degree Fahrenheit, or 0.5 degrees Celsius, in the past 50 years, primarily because of human-generated emissions of greenhouses gases. (Image courtesy NASA Earth Observatory)
Indian Ocean sea levels are rising unevenly and threatening residents in some densely populated coastal areas and islands, a new study concludes. The study, led by scientists at the University of Colorado at Boulder (CU) and the National Center for Atmospheric Research (NCAR), finds that the sea level rise is at least partly a result of climate change.
Sea level rise is particularly high along the coastlines of the Bay of Bengal, the Arabian Sea, Sri Lanka, Sumatra and Java, the authors found. The rise-which may aggravate monsoon flooding in Bangladesh and India-could have future impacts on both regional and global climate.
The key player in the process is the Indo-Pacific warm pool, an enormous, bathtub-shaped area spanning a region of the tropical oceans from the east coast of Africa to the International Date Line in the Pacific. The warm pool has heated by about 1 degree Fahrenheit, or 0.5 degrees Celsius, in the past 50 years, primarily because of human-generated emissions in greenhouses gases. (more…)
Sea Level Rising Along U.S. Atlantic Coast According to Environmental Scientists
An international team of environmental scientists led by the University of Pennsylvania has shown that sea-level rise along the Atlantic Coast of the United States was 2 millimeters faster in the 20th century than at any time in the past 4,000 years.
Sea-level rise prior to the 20th century is attributed to coastal subsidence. Put simply, land is being lost to subsidence as the earth continues to rise in response to the removal of the huge weight of ice sheets during the last glacial period. Using sediment cores from the U.S. Atlantic coast, researchers found significant spatial variations in land movement, with the mid-Atlantic coastlines of New Jersey, Delaware and Maryland subsiding twice as much as areas to the north and south. Coastal subsidence enhances sea-level rise, which leads to shoreline erosion and loss of wetlands and threatens coastal populations.
Researchers corrected relative sea-level data from tide gauges using the coastal-subsidence values. Results clearly show that the 20th-century rate of sea-level rise is 2 millimeters higher than the background rate of the past 4,000 years. Furthermore, the magnitude of the sea-level rise increases in a southerly direction from Maine to South Carolina. This is the first demonstrated evidence of this phenomenon from observational data alone. Researchers believe this may be related to the melting of the Greenland Ice Sheet and ocean thermal expansion. (more…)
Sea-level Rise May Pose Greatest Threat to Northeast US, Canada
An aerial view of Long Island shows its low-lying shores, vulnerable to sea-level rise effects. (New York State Department of Environmental Conservation)
The melting of the Greenland Ice Sheet this century may drive more water than previously thought toward the already threatened coastlines of New York, Boston, Halifax and other cities in the northeastern United States and Canada, according to new research.
Results of the study are being published this week in Geophysical Research Letters. They suggest that moderate to high rates of ice melt from Greenland may shift ocean circulation by about 2100, causing sea levels off the northeast coast of North America to rise by about 30 to 51 centimeters (12 to 20 inches) more than other coastal areas.
The research builds on recent reports that have found that sea level rise could adversely affect North America, and its findings suggest that the situation is even more urgent than previously believed. (more…)
New Antarctic Seabed Sonar Images Reveal Clues to Sea-Level Rise
British Antarctic Survey ship RRS James Clark Ross is equipped with sonar technology to map the seabed. (British Antarctic Survey)
Motorway-sized troughs and channels carved into Antarctica’s continental shelves by glaciers thousands of years ago could help scientists to predict future sea-level rise according to a report in the journal Geology this month (May).
Using sonar technology from onboard ships, scientists from British Antarctic Survey (BAS) and the German Alfred Wegener Institute (AWI) captured the most extensive, continuous set of images of the seafloor around the Amundsen Sea embayment ever taken. This region is a major drain point of the West Antarctic Ice Sheet (WAIS) and considered by some scientists to be the most likely site for the initiation of major ice sheet collapse. (more…)
Satellite Measures the Earth’s Gravity Field to Map Ocean Topography
Earth Survey Satellite GOCE (© Astrium GmbH / Mathias Pikelj)
The Earth explorer satellite GOCE (Gravity Field and Steady-State Ocean Circulation Explorer), built by the European Space Agency ESA, was successfully launched today at 15:21 GMT from the Russian Cosmodrome Plesetsk. GOCE is the first satellite mission within the framework of the Living Planet Programme of ESA and will map Earth’s gravity field in unprecedented detail.
From the data obtained, the GFZ - German Research Centre for Geosciences will calculate its own, high resolution gravity field. “The accuracy of the depiction of the Earth’s gravity field, well known as the ‘Potsdam Gravity Potato’ will now be enhanced by orders of magnitude”, says Prof. Dr. Hüttl, Scientific Executive Director of the GFZ. The GFZ, which looks back on many years of experience in analysis of satellite-based gravity field, measurements participates in the evaluation of GOCE data as a co-operating partner within the framework of the so called High Level Processing Facility (HPF) under the Project Managment of the Technical University Munich and together with scientific institutions from Germany, France, Denmark, Italy, Austria, Switzerland and the Netherlands. (more…)
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