Scientists are becoming increasingly concerned about the environmental impact of their work. For example, in the latest of many recent reflections on the subject, bioinformatician Hervé Philippe urges us to uncouple scientific progress from economic growth (Trends Genet. 24, 265–267; 2008). He adds his voice to those advising us to reduce our carbon footprint by attending fewer scientific conferences (see also the Editorial 'Meeting expectations' Nature 455, 836; 2008).

Regular long-distance flying can easily triple an academic's carbon footprint. During the past year, I have 'spent' about nine tonnes of carbon, two-thirds of this on plane trips. Yet I am a good consumer otherwise (see, and I don't even own a car. Such figures are particularly hard for field ecologists to stomach, as we hope our long-term work will highlight the environmental consequences of climate change and may ultimately influence the public and policy-makers.

Take, for instance, the dynamic field of conservation biology. Most of its best researchers are based at universities in the Northern Hemisphere, but most of their field sites are located in developing countries in the south. These hotshots and their students use up tonnes of fuel each year in commuting trips. In fact, those who are particularly renowned and most involved in environmental politics become 'constant fliers' who are always jetting off to field sites and meetings.

I estimate that such behaviour can potentially increase an individual's carbon footprint to ten times their national average. Of course, plenty of businessmen have similar or larger carbon footprints, but few of them would claim that their journeys are good for the environment. One is left wondering whether the carbon footprints of ecologists outweigh the environmental benefits of their findings and of their lobbying.

One way around this problem is to promote conservation biology on site, with improved local academic training (see, for example,, local research leaders and fewer but longer stays by foreign visitors. With regard to environmental politics, one faces the classic dilemma between personal restraint (I stay at home and work in the garden) and energy-demanding public involvement (I fly daily to help ban overfishing).

The outcome is a personal decision that may be dictated more by ambition than by environmental awareness. Nevertheless, as a German environmental campaigner told me 15 years ago, “Industry would be all too pleased if we did not attend distant meetings because we refuse to board aeroplanes.”