US Unveils Major Plan To Cut Carbon Emissions
The US government has proposed the first national limits on carbon dioxide, as part of President Barack Obama's efforts to tackle climate change.
The administration aims to bypass Congress with the plan for a 30% cut in power plants' carbon emissions by 2030, from 2005 levels.
But it is already meeting stiff resistance from Republicans and politically vulnerable Democrats in coal-producing states, while legal challenges from industry groups are also expected.
Mr Obama said at the weekend that the new limits would eliminate up to 100,000 asthma attacks and 2,100 heart attacks in the first year.
The 645-page rule, to be finalised next year, gives each US state a flexible 2016 deadline to submit plans for how they will meet the target.
The move comes after a UN panel of scientists warned in March that climate change is already affecting every continent and will grow substantially worse unless greenhouse emissions are curbed.
The Environmental Protection Agency's (EPA) aim is to tackle the single largest source of the pollution blamed for heating the planet - carbon dioxide emitted from power plants.
Such plants produce about 40% of electricity in the nation and one-third of the carbon pollution that makes the US the second largest emitter of greenhouse gases.
EPA Administrator Gina McCarthy said: "This plan will clean the air we breathe while helping slow climate change so we can leave a safe and healthy future for our kids."
But critics say the rules will kill jobs, drive up electricity prices and force power plants across the country to close their doors.
The timing of the announcement - just months ahead of the midterm elections - is also a source of concern for politicians on both sides of the aisle.
Senate Minority Leader Mitch McConnell called the proposal "a dagger in the heart of the American middle class".
But Al Gore, the former US vice-president and climate crusader, said it was "the most important step taken to combat the climate crisis in our country's history".
The US has more than 600 coal-fired plants and some states are more dependent than others on the fuel - West Virginia gets 96% of its power from coal.
Two West Virginia lawmakers - Democratic Representative Nick Rahall and Republican Representative David McKinley - said they plan legislation to block the measure.
Mr Rahall vowed to "prevent these disastrous new rules from wreaking havoc on our economy in West Virginia".
Also sparking debate is the use of a 1970 law that the Obama administration cites as giving the president executive powers to implement the rules without congressional approval.
Mr Obama was forced to rely on the Clean Air Act after his attempts to require binding cuts through a so-called cap-and-trade system failed in the Senate four years ago.
The new plan does not call for closure of coal plants, but requires states to adapt their electricity grids to alternative sources of power such as wind and solar.