The kind of research results that make you wonder what humans can really — and effectively — do to guard against rising sea levels. New research shows global sea level has been rising two and a half times faster the past 20 years than it had in the last eight decades of the 20th century. Rutgers researcher Robert Kopp and colleagues from Harvard did the study. Professor Kopp told NJTV News Correspondent Michael Hill that more rapidly rising temperatures over the last three decades have contributed to the quicker rates of sea level rise.
“What we’ve seen over the last 20 years is that the massive ice sheets at our poles in Antarctica and Greenland have started to contribute to sea level rise. And one of the key findings from our research is that over 1900 to 1990, the rate of sea level rise is such that there may not have been much of a contribution over that period from the ice sheets. In addition, the planet’s been warming up faster over the last 30 years and that’s been increasing the rate at which the ocean’s been expanding as it takes up heat,” Kopp said.
According to Kopp, this rate of sea level rise hasn’t been seen before in human history. He said geological records show periods of significantly greater sea level rise, but not for thousands of years and back then, there was still a large ice sheet in North America.
Coastal states are vulnerable to this type of change, including New Jersey. Kopp said a good chunk of the state’s GDP happens along the coast and there are many properties there. “The projected sea level rise for the 21st century could more than double the average annual losses in New Jersey just by the middle of the century from coastal storms,” he said.
Kopp said society has to think about how to envision the future of the shore. “If we look forward to the end of this century, likely projections for sea level rise along the shore are on the order of about four feet, but it could be even more than that. It could be as much as six or seven feet. Likely projections for the middle of the century are in the range of about one and a half to two feet. We have to ask ourselves what does a shore look like with that amount of rise? I think for the next couple decades we’re facing levels of sea level rise we can adapt to through things like shore replenishment, but we really have to think about what we’re going to look like as a state and as a coastal state if we’re looking at four feet or six feet of sea level rise by the end of the century,” he said.
The study focused on interpreting tide gauge records. “If you look at tide gauge records, if you look at them using modern statistics and physical models and take into account all the key processes that contribute to sea level change, sea level actually was rising slower from 1900 to 1990 than we previously thought. But over the last 20 years, other estimates are right on target. So that means that the rate of increase has been greater than previously thought,” Kopp said. “The fact that we’ve had this acceleration over the last 20 years and that it’s larger than previous papers have suggested, it’s certainly driven some interest. But fundamentally, it’s about interpreting the past, providing the context for some of these projections of sea level rise.”