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
and JavaScript.
Gauging how the planet will respond to rising emissions remains one of the biggest questions in climate science. Mason Inman looks at how close we are to answering it.