US President Barack Obama has unveiled a new plan to cut greenhouse gas emissions from coal-fired power plants at home, international media outlets reported.

Whereas an earlier version of the plan required a 30% cut in carbon dioxide emissions by 2030, compared to 2005 levels, the new version increases that target to 32%.

No challenge poses a greater threat to humanity's future than climate change, Obama warned on Monday, unveiling the biggest measure to combat global warming ever attempted by the US.

"We're the first generation to feel the impact of climate change and the last generation that can do something about it,” Obama said in a video address.

"We only get one home. We only get one planet."

United States power plants account for just 5% of global carbon dioxide emissions but Obama administration officials have said that if the country leads on this issue, other nations would follow. Carbon dioxide emissions from power plants fell 15% between 2005 and 2013, meaning the US is halfway to the target.

The new plan, which will significantly increase electricity generation from wind and solar plants and force a switch away from coal, is expected to trigger a wave of opposition from both utilities and state-level authorities.

According to Senate Majority Leader Mitch McConnell the new plan would shut down coal-fired power plants and drive up electricity costs.

"I will do everything I can to stop it,” McConnell said.

But businesses such as Nestle, Unilever, L’Oreal, eBay and Levi Strauss, as well as investors sent a letter to 29 state governors to support the new rules which they said would create jobs and benefit the overall economy.