After a year in the works, the US government is expected to roll out new CO2 regulations for power plants on Monday. The US daily Wall Street Journal and the New York Times both broke the story ahead of the planned announcement, citing sources briefed on the new legislation.

Ahead of the unveiling, US President Barack Obama spoke of the necessity of addressing global warming.

"The shift to a cleaner energy economy won't happen overnight, and it will require tough choices along the way," Obama said in his weekly radio address on Saturday.

"But a low-carbon, clean energy economy can be an engine of growth for decades to come."

Few details were immediately available about the proposal, which was to be unveiled by the Environmental Protection Agency (EPA). According to initial reports, the EPA regulations would require companies to reduce their CO2 emissions by one-third by 2030 compared to their 2005 output.

The new laws would allow individual states to decide the best strategy for implementation. They would have the option of introducing renewable energy, energy-efficiency technologies and using cap and trade programs for companies struggling to comply with the new limits.

The US president has been met with stark opposition from Republican lawmakers over his attempts to tackle climate change during his two terms. However, the pushback against his latest plan could come from both sides of the aisle, as both Democrats and Republicans from coal-producing states face mid-term elections.

kms/jm (AP, AFP, dpa)