A 2°C limit on average global warming would lead ocean levels to rise by 25 metres over the next 2,000 years and stay there for at least 10,000, twice as long as human history, concludes a study in the journal Nature Climate Change.
If today’s greenhouse gas emission patterns are not severely curtailed, sea level rise will total 50 metres, the report states.
“We can’t keep building seawalls that are 25 metres high,” said study lead Prof. Peter Clark of Oregon State University. “Entire populations of cities will eventually have to move.”
He adds that “much of the carbon we are putting in the air from burning fossil fuels will stay there for thousands of years.” So “people need to understand that the effects of climate change won’t go away, at least not for thousands of generations.”
Since most research focuses on climate change impacts through 2100, they miss the long-term, civilization-shifting impacts of ice loss and sea level rise, The Guardian notes.
“The long-term view sends the chilling message of what the real risks and consequences are of the fossil fuel era,” said co-author Prof. Thomas Stocker of the University of Bern, one of the world’s leading climate scientists. “It will commit us to massive adaptation efforts so that, for many, dislocation and migration becomes the only option.”
About 80% of the sea level rise would result from the loss of the Antarctic ice sheet, and another Nature Climate Change study “reveals that some large Antarctic ice sheets are dangerously close to losing the sea ice shelves that hold back their flow into the ocean,” The Guardian reports.
“The actions of the next 30 years are absolutely crucial for putting us on a path that avoids the [worst] outcomes and ensuring, at least in the next 200 years, the impacts are limited and give us time to adapt,” Stocker told Carrington.
“If you are very optimistic and think we will be in the position by 2050 or 2070 to have a global-scale carbon removal scheme—which sounds very science fiction—you could pump down CO2 levels. But there is no indication that this is technically possible.”
“We are making choices that will affect our grandchildren’s grandchildren and beyond,” added Harvard University Prof. Daniel Schrag. “We need to think carefully about the long time scales of what we are unleashing.”