By Megan Sever
Rising seas that swamp cities and coastal infrastructure could cost the world more than 4 percent of the global economy each year by 2100 — far more than previously estimated — unless urgent action is taken both to reduce greenhouse gas emissions and to prepare for such impacts from climate change, a new study finds.
That worst-case scenario, which assumes that large amounts of polar ice will melt, could come to trillions of dollars. That’s “not peanuts,” says Thomas Schinko, a climate economist and deputy director of the Risk and Resilience program at the International Institute for Applied Systems Analysis in Vienna. “This would lead to a completely different world.”
Given the risks, it’s hard to imagine that people won’t make any effort to adapt to a world with more flooding and coastal erosion, Schinko says. So that worst-case scenario is “not a very realistic scenario.” But regardless if the 4 percent global loss actually materializes, he says, the shocking number should show policy makers what could happen if they don’t act soon.
If countries lower greenhouse gas emissions enough to prevent the global temperature from rising more than 2 degrees Celsius above preindustrial levels, but do nothing else to prepare for rising seas, costs are projected to be more than 3 percent of global gross domestic product each year by 2100, the report says. But if countries lower emissions and prepare for sea level rise, costs can be limited to about 0.4 percent of global GDP or less, Schinko and his colleagues found.