Electronic publishing circumvents environmental issues caused by paper use and the shipment of heavy journals. But more thrift is needed to reduce the energy consumed by Internet servers, which already accounts for 2% of global energy production (see, for instance, go.nature.com/dmqn9a).

Large video and PDF files are downloaded and distributed by e-mail, often thousands of times. Minimizing the size of such files would reduce server energy usage and allow easier access by people in developing countries and rural areas that have slow Internet connections.

Server energy is also wasted in distributing figures at unnecessarily high resolution. Governments and public organizations are particularly guilty (see, for example, an 11-megabyte PDF from the European Research Council: go.nature.com/lwcuyx).

More scientific journals should ask authors to submit their manuscripts with low-resolution illustrations, which can then be upgraded for publication. Publishers of open-access journals might even consider offering a discount on publication charges for manuscript files that are smaller than, say, one megabyte.