The real potential of global sea level rise might be much worse than even the worst case scenario according to a group of NASA scientists at a press conference on Wednesday, Aug 27. The scientists on the panel said that most of the scenarios analyzed by climate models don’t take into account the potentially devastating effects of glaciers and ice sheets breaking up and rapidly melting in the ocean. The effects of sea level rise are already being seen, and now NASA predicts we’re in for at least three feet of sea level rise in the coming decades with no hope of reversing the effects.
Much of sea level rise can be attributed to two factors. CBS News reported that at least one-third of the rising sea level is simply due to the planet getting hotter, which causes water to expand. “When heat goes under the ocean, it expands just like mercury in a thermometer,” said Steve Nerem, lead scientist for NASA’s Sea Level Change Team at the University of Colorado in Boulder. The other major factor, which accounts for the two-thirds of sea level rise, is the melting of ice sheets in Greenland and Antarctica.
The ice sheets have been a major headache for scientists trying to get an idea on how quickly the seas are rising, largely because we have never seen the collapse of ice sheets on the scale that we are seeing now. “Ice sheets are contributing to sea level rise sooner, and more than anticipated,” said Eric Rignot a glaciologist at NASA’s Jet Propulsion Laboratory in Pasadena, California and the University of California, Irvine.
The current worst case scenario predicted by the International Panel on Climate Change, an organization created by the United Nations to model and analyze the effects of climate change, is a rise of 21 feet over the next century. But Rignot thinks that even this prediction fails to capture the potential threat of sea level rise because the IPCC model only takes into account temperature changes that happen on the surface of glaciers, while looking over the rapid melt that happens when a glacier calves and breaks up in the ocean.
Gizmodo reported that NASA has determined that Earth’s global sea level has risen by about 2.75 inches over the last 23 years, and will probably rise another .12 inches per year with regional variances. To a degree, NASA believes we’re committed to a large degree of sea level change. “Given what we know now about how the ocean expands as it warms and how ice sheets and glaciers are adding water to the seas, it’s pretty certain we are locked into at least three feet of sea level rise, and probably more” said Nerem.
However, this is far from the worst possibility, as scientists are still working that out. Meanwhile, according to Motherboard article, NASA is completely watch and take notes on how the oceans consume Earth’s coastlines, with a full suite of satellites and observational plane flights lined up for the event. NASA’s press conference and panel on the rising sea level can be viewed in its entirety here.