These Scientists Say Sea Levels Could Rise Much More Than We Thought

Current research may dramatically underestimate the severity of sea level rise thanks to climate change in the coming decades, a group of scientists warned this week.

The findings, published in the journal Atmospheric Chemistry and Physics, suggest that even ambitious efforts to stem greenhouse gas emissions and limit warming to 2°C (3.6°F) by 2100 may be inadequate. The paper’s researchers, a group that includes famed climate scientist Columbia University researcher James Hansen, argue that a little understood feedback mechanism could drive sea level rise of several meters by the end of the century and contribute to superstorms of unprecedented strength. The coastal rise alone would be enough to drown many of the world’s coastal cities, the researchers say.

Hansen, best known for sounding the alarm on global warming in the 1980s, said in a video accompanying the paper that he doubts that the world has crossed a “point of no return” but said it was a possibility. “We are in a position of potentially causing irreparable harm to our children, grandchildren and future generations,” Hansen says. “This is a complex story, but one with important practical implications.”

The finding, previously published in draft form last year, departs from most consensus research on the topic of sea level rise—a fact that Hansen and his counterparts state up front. The researchers suggest that most climate models don’t account for the feedback mechanisms that make the correlation between temperature rise and sea level rise non-linear. Changes to circulation of warm and cold water in the Atlantic due to ice melting in Greenland and Antartica could have unanticipated effects, according to the study.

The Intergovernmental Panel on Climate Change (IPCC), an international body that publishes the scientific consensus on global warming used by many policymakers, has suggested that sea levels have risen by a few millimeters each year since the early 1990s. published published in the journal PNAS has suggested that sea levels will rise between 0.75 m (2.5 ft) and 1.9 m (6.2 ft) by 2100 as warming increases.

Still, the researchers suggests that even those who may be more inclined to follow conservative estimates of sea level rise should heed the broader call to act on climate change. Hansen suggests a “gradually rising” tax on fossil fuels to encourage the transition as the beginning of a solution to the problem.

“Do you agree we agree that we have reached a dangerous situation?” he asks. But “That’s the bottomline.”