President Obama issued an executive order on Dec. 5, calling for an increase in solar, wind, and other renewable energy for federal agencies, to 20 percent by 2020 - three times more than the agencies currently use.
Obama argued for the necessity of tackling climate change. Al Gore said it was the "best presidential address on climate" ever.
As part of a planned comprehensive climate change strategy, President Obama will announce an effort in July to reduce carbon dioxide emissions.
Many environmentalists are encouraged by the fact that Obama is now starting to discuss climate change more.