Hot off the (press release) presses:
In a groundbreaking move, Warner Bros. Pictures and Participant Productions have made Syriana, a multi-layered political thriller about the global oil industry, the first major motion picture to be "climate neutral" by offsetting 100% of carbon dioxide emissions generated by the production during filming — an estimated 2,040 tons — with investments in renewable energy. Investments will be made in wind and methane power and, specifically, in projects that may not otherwise happen without this support.
NativeEnergy worked with Syriana’s producers to calculate the amount of carbon dioxide emissions from all of Syriana’s production activities, including filming, air travel, rental car and truck emissions, hotel energy use, diesel generators used on location, office and warehouse energy use, and emissions from shipping. NativeEnergy then offset those emissions by purchasing renewable energy credits, or "green tags," from renewable energy projects.
(I added the links. Haven’t found the press release online yet — will link when I do.)
Update [2006-1-18 15:15:9 by David Roberts]: Hm … DavoJ says in comments that The Day After Tomorrow was in fact the first climate-neutral blockbuster, and IMDb at least seems to back him up. Anybody got more info on this?