President Obama said in his inaugural speech that he will make climate change a priority in his second term.
The president said failing to address the global warming threat would betray the world's children, and all future generations.
Mr. Obama acknowledged that some people do not believe human activity such as burning fossil fuels is causing the Earth to heat up. But he said no one can avoid the consequences of a warmer planet, including drought, fires and stronger storms.
The president said the United States must lead the transition toward sustainable energy sources such as wind and solar power.
Many Republicans and others who oppose Mr. Obama's policies say the U.S. economy cannot afford to move away from traditional fossil fuels. They cite theories that global warming is a part of the natural cycle of climate change.
However, environmental groups cheered the president's commitment to action on climate change.
The Sierra Club said the president's remarks were heartening. It says global warming is a pressing challenge for the entire world.
The Natural Resources Defense Council says Mr. Obama's sentiments should be read a call for action on environmental issues.