Ice sheets are melting, glaciers are shrinking and the planets oceans are changing in unprecedented ways, according to a shocking new report released by the United Nations on Wednesday, the latest confirmation that climate change is already wreaking havoc around the globe.

The findings, published by the Intergovernmental Panel on Climate Change , or IPCC, the leading U.N. body studying human-caused global warming, issue stark warnings for hundreds of millions of people living in low-lying or coastal areas and come amid a renewed call from scientists who say the planet is quickly running out of time to stave off the worst impacts of climate change. The report was written by more than 100 scientists from 30-plus countries, and is the third such paper published by the IPCC over the past year (an August report focused on protecting land , and one last October found time was rapidly running out to avoid catastrophic warming).

Each year that we delay action, ocean waters warm and become more acidic. This fuels hurricanes, kills coral reefs, and threatens the safety and livelihoods of the 40% of the worlds population who lives within 60 miles of the coast, Miriam Goldstein, a director of ocean policy at the Center for American Progress, said in a statement this week. To protect the oceans natural ability to store carbon, to feed billions of people across the world, and to save ocean ecosystems, we must substantially reduce greenhouse gas emissions as quickly as possible.

The report, which focuses on the ocean and the cryosphere, or the frozen parts of the planet, comes amid worldwide calls for dramatic climate action. More than 4 million people around the globe staged mass climate strikes in thousands of cities last Friday, spurred by the 16-year-old Swedish activist Greta Thunberg, and many more are expected to step out again on Sept. 27.