My carbon footprint
Two or three months ago I posted to say that I had invested in a bike that can carry children, and that the result of that investment was that I would be able to use my car much less. That has indeed been the case, so I have cut down my carbon footprint. I have also switched my gas and electricity provider to a company that uses renewable energy -- for the electricity at least. It took me a short while to work out how switching could do any good, given that I'm still getting the electricity from the national grid, but of course the answer is that my paying this new company means that they have to supply a certain amount of electricity to the national grid (which they do using a combination of wind, solar and tidal power) that would otherwise have had to be supplied by a company that burns carbon.
But all this has to be set against the fact that I accepted an invitation to speak at the joint AMS-MAA meeting in Seattle in January, and the amount of carbon I'll be responsible for emitting will dwarf the amounts that I have not emitted as a result of the measures described above. This bugs me, so I've done something else to try to salve my conscience, which is to give a donation to a charity called Cool Earth.
Cool Earth's mission is to save rainforest from destruction. This has many good effects -- helping to preserve the lifestyles of indigenous people, maintaining biodiversity, etc. -- but the one that concerns me most is that it stops a carbon sink being destroyed, which has a double benefit since burning the forest itself emits a lot of carbon. Moreover, Cool Earth tries to use your money as efficiently as possible, creating "shields" of protected forest that make other bits of forest inaccessible and therefore also unlikely to be destroyed.
I've no idea how reliable the following estimates are, but they say that the £120 I have given them is equivalent to saving two acres of rainforest, and elsewhere they say that saving an acre of rainforest is stopping emissions that are equivalent to driving a car 32 times round the world, or 800,000 miles. (I went for two acres rather than one because of this uncertainty.)
I realize that this kind of action is controversial. Some people object to the idea that one can merrily emit carbon and then pay for a few trees to make up for it: better, they say, not to emit the carbon in the first place. But it's not obviously better. In fact, I'd say it is decidedly better to emit carbon and save trees if the total amount of carbon that will be emitted is significantly less. (Yes, I could have not gone to Seattle and still paid for two acres of rainforest, but I'm not claiming to have optimized my behaviour -- for that I'd need to do things like moving to a smaller house and using the difference in price to save hundreds of acres of rainforest.) Another issue is that this solution doesn't scale up, since if everybody did it then there wouldn't be enough rainforest that could be saved, or at least not as efficiently as it currently can. To which I reply that for the time being few enough people are doing it that this problem has not yet arisen. I may make it harder for people in the future to reduce their carbon footprints, but I'll still have done some good during the years before the difficulty becomes noticeable.
Yet another objection is that even if I'm doing the best I can carbon-wise for the money, it might still be better to spend the money on another charity, such as one of the charities recommended by GiveWell (which tries to work out how you can do most good per pound spent). To counter this objection I will try not to make the money spent on Cool Earth subtract from what I would have spent on GiveWell. Of course, that's not an entirely rational argument, since if I could do more good per pound with GiveWell, then surely I ought to do that. But climate change seems such a big threat that I want to do my bit to mitigate it. And part of the reason I'm writing this post is to publicize the activities of Cool Earth: maybe by doing so I can have a bigger effect.
Here's a recommendation to anyone who is organizing a conference: add to your budget enough money to save a few acres of rainforest to make up for all those plane journeys that your conference is causing to happen. I'm wondering whether in future I should accept invitations to travel only if my hosts are prepared to make my trip carbon neutral in this way.