The Dave Matthews Band has announced that it will not only offset the carbon dioxide (CO2) emissions from its current tour but from all of its tours since 1991. The group is working with NativeEnergy and Clean Air-Cool Planet, providing funds ‘to help build new wind projects by purchasing shares of the renewable energy credits (RECs) the projects are expected to generate over their operating lives.’ Meanwhile, fan web site AntsMarching.org is stepping up as well by issuing a challenge to its visitors, encouraging each of them to offset all emissions since their first DMB show (why not head over there and do the same?).