The president says the level will stabilize by that year, but he sets no cap.
Designers look to giant kites, bubbles, and new propellers to save on fuel costs and reduce pollution.
By December 2009, binding greenhouse-gas emissions policies will be set for developing countries.
Both leading Democrat and Republican candidates vie to show they can tackle global warming.
At the meeting of the world's biggest polluters in Hawaii this week, host US has a chance to show it is serious about action on climate change.