How will we face the danger of rising seas?

Tim Folger an American science and nature writer, contributing editor at the Discover Magazine and a science writer for other magazines, wrote an article about sea-levels rice in September 2013 issue of National Geographic.  In this article “Rising Seas”  he argues that

“A profoundly altered planet is what our fossil-fuel-driven civilization is creating, a planet where Sandy-scale flooding will become more common and more destructive for the world’s coastal cities. By releasing carbon dioxide and other heat-trapping gases into the atmosphere, we have warmed the Earth by more than a full degree Fahrenheit over the past century and raised sea level by about eight inches. Even if we stopped burning all fossil fuels tomorrow, the existing greenhouse gases would continue to warm the Earth for centuries. We have irreversibly committed future generations to a hotter world and rising seas.

In May the concentration of carbon dioxide in the atmosphere reached 400 parts per million, the highest since three million years ago. Sea levels then may have been as much as 65 feet above today’s; the Northern Hemisphere was largely ice free year-round. It would take centuries for the oceans to reach such catastrophic heights again, and much depends on whether we manage to limit future greenhouse gas emissions. In the short term scientists are still uncertain about how fast and how high seas will rise. Estimates have repeatedly been too conservative.”

“Six years ago the Intergovernmental Panel on Climate Change (IPCC) issued a report predicting a maximum of 23 inches of sea-level rise by the end of this century. ………….. As the IPCC prepares to issue a new report this fall, in which the sea-level forecast is expected to be slightly higher, gaps in ice-sheet science remain. But climate scientists now estimate that Greenland and Antarctica combined have lost on average about 50 cubic miles of ice each year since 1992—roughly 200 billion metric tons of ice annually. Many think sea level will be at least three feet  (about 90cm) higher than today by 2100. Even that figure might be too low.”

Folger discusses with engineers, scientists, architects and citizens from New York, Miami, New Orleans and Rotterdam, Netherlands about the factors contributing to sea-level rise and the current projections. One of the scientists being interviewed for the article was Gavin Foster, a geochemist at the National Oceanography Centre,  University of Southampton and Principal Investigator of the Descent into the Icehouse Project. Gavin says that

“With business as usual, the concentration of carbon dioxide in the atmosphere will reach around a thousand parts per million by the end of the century. …..Such concentrations haven’t been seen on Earth since the early Eocene epoch, 50 million years ago, when the planet was completely ice free. According to the U.S. Geological Survey, sea level on an iceless Earth would be as much as 216 feet higher than it is today. It might take thousands of years and more than a thousand parts per million to create such a world—but if we burn all the fossil fuels, we will get there.

No matter how much we reduce our greenhouse gas emissions, we’re already locked in to at least several feet of sea-level rise, and perhaps several dozens of feet, as the planet slowly adjusts to the amount of carbon that’s in the atmosphere already. A recent Dutch study predicted that the Netherlands could engineer solutions at a manageable cost to a rise of as much as five meters, or 16 feet. Poorer countries will struggle to adapt to much less. At different times in different places, engineering solutions will no longer suffice. Then the retreat from the coast will begin. In some places there will be no higher ground to retreat to.”

Read the article here

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