Study on rising sea levels likely confirms existence of global warming

December 01, 2012

Study on rising sea levels likely confirms existence of global warming

Oceans continue to rise, according to new study.

A newly released study finds that ice sheets in Greenland and Antarctica are disappearing three times faster than they were two decades ago, the latest evidence supporting the existence of global warming.

The study was published in the journal Science and is considered an extremely accurate portrayal of ice melts in these polar regions. According to the paper’s authors, the rapid polar ice melting has caused an increase in sea level that may become problematic to low coastal regions.

Perhaps the most alarming data found by the researchers was in Greenland where the ice was melting an estimated five times the rate it was in the mid-1990s. Melt from Greenland accounted for a whopping two-thirds of the polar ice melt. Due to a slower melt rate, just one-third of the world’s melted ice came from Antarctica, despite being larger in size than Greenland.

The published data was collected by 47 experts over the span of two decades. The journal article compiled results taken from 50 separate ice melt studies around the world and is the first of its kind. Erik Ivins of NASA’s Jet Propulsion Laboratory, and Andrew Shepherd, a professor at the University of Leeds, led the massive project and coordinated the dozens of scientists involved.

Shepherd estimates that the data compiled in the new study is two to three times more reliable than previous studies on melting ice and rising sea-level. The current go-to report on this subject, which is used by the Intergovernmental Panel on Climate Change, or IPCC, was created in 2007.

The study used by the IPCC covers the increasing ice melt in Greenland and Antarctica and even reports a sheet loss within the range of the new study. However, the IPCC report did not consider a crucial question answered by Shepherd and Ivans’ team: could Antarctica be growing instead of shrinking?

Shephard thinks that without answer this question and others like it, scientists would not be able to announce, with confidence, how the ice sheets have changed for certain.

“This will give the wider climate science community greater confidence in ice losses and lead to improved mode predictions of future sea-level rise,” he said.

The team of scientists credited advancements in satellite technology, saying coordinated efforts among the international scientific community will eventually allow for more accurate predictions of how the climate will be affected by global warming.

“The success of this venture is due to the cooperation of the international scientific community, and due to the provision of precise satellite sensors by our space agencies,” said Shepherd. “Without these efforts, we would not be in a position to tell people with confidence how the Earth’s ice sheets have changed, and to end the uncertainty that has existed for many years.”

Julie Brigham Grette, a professor at the University of Massachusetts Amherst, believes the recent Hurricane Sandy demonstrates just how important a solid understanding of the rising sea-level is. “People don’t understand why we’re talking about a few millimeters,” she said. “A half-foot of rise on the Eastern Seaboard makes it easier for a storm coming up the East Coast to cause flooding.”

It may seem as though ice melt, and thus sea-level rise is to blame for intense hurricanes, like Sandy, however, according to Grette, the real problem is global warming. According to Grette, increased temperatures from trapped greenhouse gases are causing oceans to warm and expand. She expects sea level to move up the coast by at least 40 inches in the next 90 years.

The study is likely to reinforce concerns that low-lying cities are not taking adequate precautions to avoid rising sea levels. A number of international organizations have begun discussing possible impacts of rising sea levels, including the possibility to widespread population displacement. Still, the scientific community welcomed the study’s results, saying it will lay the groundwork for better predictive models that could aid policy makers in their decision-making.

“This project is a spectacular achievement. The data will support essential testing of predictive models, and will lead to a better understanding of how sea-level change may depend on the human decisions that influence global temperatures,” said Professor Richard Alley, a climate scientist at Penn State University who was not involved in the study.


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