The oceans are rising faster than at any point in the last 28 centuries, and human emissions of greenhouse gases are primarily responsible, scientists reported Monday.
They added that the flooding that is starting to make life miserable in many coastal towns — like Miami Beach; Norfolk, Va.; and Charleston, S.C. — was largely a consequence of those emissions, and that it is likely to grow worse in coming years.
The scientists confirmed previous estimates, but with a larger data set, that if global emissions continue at a high rate over the next few decades, the ocean could rise as much as three or four feet by 2100, as ocean water expands and the great ice sheets in Greenland and Antarctica begin to collapse.
Experts say the situation will grow far worse in the 22nd century and beyond, likely requiring the abandonment of many of the world’s coastal cities.
“I think we can definitely be confident that sea-level rise is going to continue to accelerate if there’s further warming, which inevitably there will be,” said Stefan Rahmstorf, a professor of ocean physics at the Potsdam Institute for Climate Impact Research in Germany and co-author of a paper released Monday by the Proceedings of the National Academy of Sciences.
Sign Up for the Science Times Newsletter
Every week, we'll bring you stories that capture the wonders of the human body, nature and the cosmos. Coming soon.
“Ice simply melts faster when the temperatures get higher,” Dr. Rahmstorf added. “That’s just basic physics.”
In a report issued at the same time as the scientific paper, a climate research and communications organization in Princeton, N.J., Climate Central, used the new findings to calculate that roughly three-quarters of the tidal floods now occurring in towns along the American East Coast would not be happening in the absence of sea-level rise caused by human emissions.
The lead author of that report, Benjamin H. Strauss, said the same was likely to be true on a global scale, in any coastal community that has seen an increase of saltwater flooding in recent decades.
Local factors do come into play, though: Communities on land that is sinking, as in the Chesapeake Bay region of the United States, are being hit especially hard by the rising sea level.
Short Answers to Hard Questions About Climate Change
The issue can be overwhelming. The science is complicated. We get it. This is your cheat sheet.
Tidal floods are occurring more frequently, and are becoming a strain in many towns by killing lawns and trees, polluting supplies of fresh water, blocking streets in the middle of sunny afternoons and sometimes stranding entire island communities for hours by covering the roads to the mainland.
“I think we need a new way to think about most coastal flooding,” Dr. Strauss said in an interview. “It’s not the tide. It’s not the wind. It’s us. That’s true for most of the coastal floods we now experience.”
The new research was led by Robert E. Kopp, an earth scientist at Rutgers University who has won respect from his colleagues by bringing elaborate statistical techniques to bear on longstanding problems, like understanding the history of global sea level.
Scientists already knew that the sea level rose drastically at the end of the last ice age, by almost 400 feet, causing shorelines to retreat by up to 100 miles in places. They also knew that the sea level had basically stabilized, like the rest of the climate, over the past several thousand years, the period when human civilization arose and spread across the earth.
No comments:
Post a Comment