'Game-Changer': Confirming Fears, Satellites Show Fast-Rising Seas

"We are already seeing signs of ice sheet instability in Greenland and Antarctica, so if they experience rapid changes, then we would likely see more than 65 centimeters of sea level rise by 2100."
—Steve Nerem, lead author

Rather than using the typical tide-gauge data, a team of scientists from across the U.S. turned to satellite data from the past 25 years to study the annual rate of global sea level rise.

They found that oceans are encroaching on coastlines worldwide at a greater pace with every passing year, as detailed in a report (pdf) published Monday in the Proceedings of the National Academy of Sciences.

Due to greenhouse gas emissions, largely generated by modern agricultural and dirty energy practices, the planet's warming atmosphere and oceans are causing ice sheets in Greenland and Antarctica to melt quickly, which the researchers say is producing "climate-change driven accelerated sea level rise."

"It's a big deal," said the study's lead author, Steve Nerem of the University of Colorado Boulder, because these findings indicate that the data-based projections from past studies that relied on a constant rate of sea level rise are too conservative.

"This acceleration, driven mainly by accelerated melting in Greenland and Antarctica, has the potential to double the total sea level rise by 2100," Nerem explained, "as compared to projections that assume a constant rate, to more than 60 centimeters instead of about 30," or about two feet instead of about one.

In fact, "65 centimeters is probably on the low end for 2100, since it assumes the rate and acceleration we have seen over the last 25 years continues for the next 82 years," Nerem added. "We are already seeing signs of ice sheet instability in Greenland and Antarctica, so if they experience rapid changes, then we would likely see more than 65 centimeters of sea level rise by 2100."

The study provides a "data-driven assessment of sea level change" that backs up climate models that were used in the most recent International Panel on Climate Change report(pdf), which showed oceans rising 52 to 98 centimenters by the end of this century.

"The acceleration predicted by the models has now been detected directly from the observations," noted study co-author Gary Mitchum of Florida's College of Marine Science. "I think this is a game-changer as far as the climate change discussion goes."

The findings elicited calls for the United States to get onboard with the rest of the world and recommit to the Paris Climate Agreement, and for other nations to take more drastic and urgent steps to reduce emissions.

Others responded with jabs directed at those who actively deny the problem and refuse to address global warming: