Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
The world’s oceans have long helped to stave off climate change by absorbing heat and carbon dioxide from the atmosphere. But that is changing, with devastating consequences for humanity in the coming decades, leading researchers warn in a high-level report commissioned by the United Nations.