The U.S. Environmental Protection Agency officially unveiled the Obama administration’s plan Monday to cut greenhouse gases 30 per cent by 2030, stressing what it says will be the economic benefits of its "clean-air revolution."

Under the plan, carbon emissions would be reduced 30 per cent by 2030, compared to 2005 levels, one of the most significant actions to address global warming in U.S. history.

"The bottom line is we have never ... had to choose between a healthy economy and a healthy environment," EPA administrator Gina McCarthy said in a Washington news conference.

McCarthy framed the changes as necessary for Americans' health and the future of the environment, but spent most of her address stressing the economic benefits.

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U.S. President Barack Obama speaks about his vision to reduce carbon pollution while preparing the country for the impacts of climate change in June. The U.S. Environmental Protection Agency touted the plan Monday as the right choice for the country's economy. (Larry Downing/Reuters)

“This is not just about disappearing polar bears and melting ice caps … this is about protecting our health and it is about protecting our homes," she said. "It’s about protecting local economies and it’s about protecting jobs.”

McCarthy said the U.S. would save money on health-care costs and insurance premiums as the reduced pollution clears the air and slows severe weather. She also said the changes will be a boon to investors, entrepreneurs and labourers as new low-carbon technologies are brought to market and built, and that any "small short-term change in electricity prices" would be in line with "a gallon of milk a month."

Canadian government urged to set similar targets for oil and gas

The U.S. announcement prompted a reaction in Canada, where NDP Leader Tom Mulcair asked Prime Minister Stephen Harper in question period when Canada would introduce promised regulations on the oil and gas industry.

Harper replied, but addressed only Canada's action on reducing emissions from coal-fired power plants.

"We actually announced the regulation of the sector two years ago," Harper said. "And not only have we been acting under the regulations this government has already brought forward, we will have a 150 per cent larger reduction than ... the United States."

However, the extent to which Canada uses coal is different than it is in the United States. In the U.S., coal accounts for 30 per cent of all carbon emissions, while in Canada the figure is 12 per cent. Canada's largest contributor to emissions is the oil and gas industry, at 25 per cent, according to figures from Environment Canada, although transportation comes a close second at 24 per cent.

Using the crucial phrase "in this sector," meaning coal, Environment Minister Aglukkaq said in question period, "We estimate we will achieve a 46 per cent reduction in greenhouse gases in this sector by 2030 compared to 30 per cent in the United States."

She did not answer a question from NDP environment critic Megan Leslie about when the government would table oil and gas regulations. But in a statement entitled "U.S. Green Plan," issued at the same time as question period, Aglukkaq says, "Our government would like to work in concert with the United States on reducing greenhouse gas emissions for the oil and gas sector." The statement did not provide a timeline.

U.S. halfway to goal, EPA says

Environmental Protection Agency data shows that U.S. power plants have reduced carbon dioxide emissions by nearly 13 per cent since 2005, or about halfway to their goal. But with coal-fired power plants already beleaguered by booming natural gas supplies and other environmental regulations, experts told The Associated Press that getting there won't be easy.

U.S. President Barack Obama has already tackled the emissions from the nation's cars and trucks, announcing rules to reduce carbon dioxide emissions by doubling fuel economy. That standard will reduce carbon dioxide by more than 1.8 billion tonnes. The power plant proposal will prevent about 390 million tonnes of carbon dioxide from reaching the atmosphere, based on the 30 per cent figure.

The push against Obama's new carbon emission standards has been strongest in some states that have large coal-mining industries or rely heavily on coal to fuel their electricity. State officials say the new federal regulations could jeopardize the jobs of thousands of workers and drive up the monthly electric bills of residents and businesses.

It remains to be seen whether new measures passed by the states will amount to mere political symbolism or actually temper what's expected to be an aggressive federal effort to reduce the country's reliance on coal.

McCarthy said she expects critics to make "tired" claims about costs and reliability. 

"The most costly thing of all that we can do is nothing," she said.

Senate Minority Leader Mitch McConnell, a Kentucky Republican, called the proposal "a dagger in the heart of the American middle class."

With files from The Associated Press