Rising Seas Could Cost the World $14 Trillion a Year by 2100

This photo taken on June 16, 2018 shows a low-lying home near sea level in the Indian Beach neighborhood of Sarasota, Florida. KERRY SHERIDAN/AFP/Getty Images

Rising sea levels could cost the global economy around $14 trillion annually by 2100 if the 2°C warming limit agreed at the Paris climate talks is breached, according to a study published in the journal Environmental Research Letters.

The Paris Agreement proposed to keep the increase in global average temperature to well below 2°C higher than pre-industrial levels in order to mitigate the worst effects of climate change. It also required nations to pursue efforts to limit the increase to 1.5°C, if possible.

"More than 600 million people live in low-elevation coastal areas, less than 10 meters [32.8 ft] above sea level," Svetlana Jevrejeva, lead author of the study from the U.K. National Oceanographic Centre (NOC), said in a statement.

"In a warming climate, global sea level will rise due to melting of land-based glaciers and ice sheets, and from the thermal expansion of ocean waters. So, sea level rise is one of the most damaging aspects of our warming climate."

For their study, the researchers examined different sea level rise projections and warming scenarios where the increase in temperatures was restricted to 1.5°C (2.7°F), 2°C (3.6°F) or not restricted at all.

In these scenarios, 1.5°C of warming led to a sea level rise of 0.52 meters (1.7 ft) by 2100, 2°C resulted in a rise of 0.86 meters (2.8 ft), and unrestricted warming led to a 1.8m (5.9 ft) increase in sea levels.

The scientists then used data from the World Bank, which groups nations into different income levels, to assess the impact of sea level rise on a global scale, as well as for individual countries.

They found that in the worst-case scenario, global annual flood costs could increase to $14 trillion per year by 2100 if sea levels rise 0.86 meters. And this figure could jump to $27 trillion annually—which would be equivalent to 2.8 percent of global GDP by the end of the century—for a rise of 1.8 meters.

Furthermore, the scientists found that higher income countries would suffer the least economic damage, thanks to their more developed flood defenses, while upper-middle income countries like China will incur the biggest costs. The researchers also suggest that sea level rises are likely to be more extreme in tropical areas.

"These extreme sea levels will have a negative effect on the economies of developing coastal nations, and the habitability of low-lying coastlines," Jevrejeva said. "Small, low-lying island nations such as the Maldives will be very easily affected, and the pressures on their natural resources and environmental will become even greater."

"These results place further emphasis on putting even greater efforts into mitigating rising global temperatures," she concluded.