Astronomy’s carbon footprint is the strangest problem you’ve never thought about (Image: G. Hüdepohl/ESO)

Astronomy produces a lot of carbon emissions, but it could be one of the greenest sciences if observatories harness their solar and wind resources

IF YOU were to draw up a list of the most pressing issues in science, it’s unlikely that astronomy’s carbon footprint would be on it. If it were, it would probably end up somewhere between effective male birth control and how to fold headphones to stop their wires getting tangled in your pocket.

Ueli Weilenmann, deputy director of La Silla Paranal Observatory in Chile, would disagree with that assessment. Recently, while grappling with the costs of running the place, he was shocked to discover the scale of the observatory’s carbon emissions (see diagram). A bit of further digging revealed that the problem is not limited to Paranal: many other observatories exude more greenhouse gas than their size betrays.

This shouldn’t be the case. By dint of their location, most observatories enjoy access to clean energy sources, but for various reasons they have been unable to exploit them. Now observatories all over the world are looking beyond obvious solutions, enlisting ingenious workarounds in their quest to go green. The possibilities for doing so run from the inspired to the mundane to the highly speculative. The potential carbon cutbacks won’t save the world, but the people running these experiments are determined to prove that big science can be clean too.

The bigger telescopes get, the further they can peer into our universe, and the better the resulting images. But the …