Humanity must rescue oceans to rescue itself, UN warns

Two days after a climate summit failed to deliver game-changing pledges to slash carbon emissions, the United Nations warned Wednesday that global warming is devastating oceans and Earth's frozen spaces in ways that directly threaten a large slice of humanity.

Crumbling ice sheets, rising seas, melting glaciers, ocean dead zones, toxic algae blooms -- a raft of impacts on sea and ice are decimating fish stocks, destroying renewable sources of fresh water, and incubating superstorms that will ravage some megacities every year, according to a landmark assessment approved by the 195-nation Intergovernmental Panel on Climate Change (IPCC).

Some of these impacts are irreversible.

The report, a digest of 7,000 peer-reviewed studies, is a sobering reminder that record greenhouse gas emissions, mostly from burning fossil fuels, are driving the planet towards a hothouse climate our species could find unable to tolerate.

But it also raises more clearly than ever before a red flag on the need to confront changes that can no longer be averted.

For some island nations and coastal cities, that will almost certainly mean finding new places to call home.

"Even if we manage to limit global warming, we will continue to see major changes in the oceans," said Valerie Masson-Delmotte, a researcher at the Laboratory for Climate and Environmental Sciences and an IPCC co-chair.

"But it will at least buy us some time, both for future impacts and to adapt."
"It doesn't take a big rise in sea level to lead to catastrophic problems," he added. "Sea level rise is not a slow onset problem -- it's a crisis of extreme weather events."