Another small thing you can do – here, now, today – to help the environment is sign up to help with the Climate Prediction experiment at http://www.climateprediction.net/
This is another one of those distributed processing concepts where spare computational power on your computer is used to solve massive problems by breaking the problem up into many small parts and just throwing computer power at it to solve it. It works like a screensaver and only kicks in when your computer is otherwise idle, so it will not eat into your computer’s capacity. And obviously you do not need to leave your computer on overnight to work on the problem – unless of course you are using 100% green electricity of course…