http://www.kaufda.de/umwelt/carbon-neutral/

“My blog is carbon neutral” is an initiative, originally started in Germany by the “Make it Green” programme, that has the goal to reduce carbon dioxide emissions. We plant a tree for your blog and thereby neutralise your blog’s carbon footprint for the next 50 years! Everyone can make a small contribution to the environment. Every tree counts!

How much carbon dioxide does your blog create? – http://www.kaufda.de/umwelt/carbon-neutral/1-tree-1-blog-how-it-works/

How you can join – http://www.kaufda.de/umwelt/carbon-neutral/how-you-can-join/