It's about time that the US got involved in the UN's efforts to halt global warming, says the group:
Participants of the two-week long 14th Conference of the Parties to the United Nations Framework Convention on Climate Change, or COP 14, will work toward drafting a successor agreement to the Kyoto Protocol, the system of mandatory carbon caps that are set to expire in 2012. The United States is the only industrialized country that has not signed the protocol.
McKibben helped launched 350.org in March to highlight what he often calls "the most important number on the planet," that is, the maximum safe ratio, in parts per million, of carbon dioxide atoms in the atmosphere. Leading scientists say that CO2 concentrations higher than 350 ppm put us at risk for catastrophic climate change. Current atmospheric concentrations are at 387 ppm and rising.
The group released a brilliant animation in June to highlight the issue (the spot was produced by Free Range Studios, which also produced The Story of Stuff, which is well worth watching if you have 20 minutes.)
The group also put together a video about thier invitation, which you can watch here: