Date published: 2006/03/04
The BBC says:
Ground-based astronomy could be impossible in 40 years because of pollution from aircraft exhaust trails and climate change, an expert says.
Aircraft condensation trails - known as contrails - can dissipate, becoming indistinguishable from other clouds.
If trends in cheap air travel continue, says Professor Gerry Gilmore, the era of ground astronomy may come to an end much earlier than most had predicted.
Aircraft along with climate change will contribute to increased cloud cover.
The timescale is based on extrapolating air traffic growth figures. The BBC has learned that the calculations were made as part of preparations for an upcoming observatory project called the Extremely Large Telescope (ELT).
The ELT is intended to probe planets around nearby stars and look for extremely faint objects in the Universe.
"It is already clear that the lifetime of large ground-based telescopes is finite and is set by global warming," Professor Gilmore, from Cambridge's Institute of Astronomy, told reporters recently in London.
"There are two factors. Climate change is increasing the amount of cloud cover globally. The second factor is cheap air travel.
"You get these contrails from the jets. The rate at which they're expanding in terms of their fractional cover of the stratosphere is so large that if predictions are right, in 40 years it won't be worth having telescopes on Earth anymore - it's that soon.
"You either give up your cheap trips to Majorca, or you give up astronomy. You can't do both."
Let's see. It's ok for astronomers to travel to the other side of the world (Hawaii, Chile, Canary Islands) to make their observations but it's not ok for the ordinary British citizen (who pays taxes which keep these astronomers in business) to take a holiday in Spain. Not to mention all the conferences astronomers (like all academics) attend, mostly by air. Sure the person flying to Spain does not pay enough of a carbon tax (the current tax is not related to carbon emissions) and that should be rectified (assuming that train commuters, people who heat and light their homes, and all the other users of energy, also pay a carbon tax). But astronomers personally pay nothing for their trips abroad (in their capacity as astronomers), never mind a carbon tax. So they are externalising the environmental damage they are causing even more than most people.
Astronomers are treading a thin line here. If you asked the general public whether they should get to fly to Spain or whether astronomers should get to do their work, the astronomy community might not like the answer. And if you believe their analysis then they are pretty much saying that in future ground-based telescopes should not be built (even if carbon emissions were plausibly reduced over the next few decades it would take decades beyond that for the effects to work through the system).
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