Full coverage: Paris Climate Agreement

The United States and China were two of the driving forces behind the approval of significant carbon reductions at last year's Paris Climate Talks. But while China is able to move ahead - President Barack Obama's domestic plan to keep global warming in check is facing legal challenges.

US President Barack Obama says his Clean Air Act comes at a critically important moment in time.

In the next 15 years-the Obama administration is proposing dramatically steering away from the use of coal. And, any new coal burning utility plants - like this one owned by the Southern Company in Kemper, Mississippi, will have to operate without spewing pollutants into the air.
This is a coal gasification plant -which turns high sulfur coal into a synthetic gas.

And -arguably among the most expensive -- Construction at this plant is three years behind schedule, with a price tag of 6.5-billion dollars -- three times the initial cost estimate.
It is also, critics contend - a microcosm of what is wrong with Obama's clean air plan - It is costly, and eliminates jobs recently outlined by Republican opposition Congressman Steve Scalise.

Legal challenges to the President's Environmental Protection Agency climate measure are mounting.
Adherence to the much ballyhooed Paris Agreement - and President Obama's pledge to reduce carbon pollution from power plants by a third, could be in jeopardy.

The legal filings, chiefly from Republican states, and utility giants, contend the president and the EPA overstepped their authority. Eventually the case is expected to make it to the US Supreme Court.