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.
The Worldwatch Institute, the private Washington-based research organisation concerned with global problems, published its latest pamphlet last week. Chris Sherwell reports
