US President Barack Obama has announced new measures to tackle climate change, promising to stamp out carbon pollution and reduce America's greenhouse gas emmissions.
Obama on Tuesday announced his most sweeping plan yet to tackle pollution and global warming, moving to deliver on a major priority he laid out in his first presidential campaign.
He ordered his administration to end the practice of coal-fired power plants dumping unlimited carbon dioxide emissions into the atmosphere, announcing the first-ever federal regulations on heat-trapping gases emitted by new and existing power plants.
The president also said an oil pipeline project from Canadian tar sands to Texas refineries should only be approved if it does not "significantly exacerbate" carbon pollution.
Canada does not think there would be a net increase in carbon emissions if TransCanada Corp builds its proposed Keystone XL pipeline from Alberta's oil sands to Texas, Natural Resources Minister Joe Oliver said on Tuesday.
"On a net basis, we don't see any increase in emissions as a result of the construction of the pipeline," Oliver told reporters in Toronto.
Environmental activists have demanded that his administration not approve the Keystone XL pipeline, while Canada's leaders have pushed for its approval.
Republican critics in Congress called his plan a job-killer that would threaten the economic recovery.
Obama dismissed the critics, saying, "That's what they said every time. And every time, they've been wrong.''
Tuesday's announcement was the first public confirmation that Obama plans to extend proposed carbon emissions controls on new power plants to existing ones.
Forty percent of US carbon dioxide emissions, and one-third of greenhouse gases overall, come from electric power plants, according to the federal Energy Information Administration.
Other parts of Obama's plan will boost renewable energy production on federal lands, increase efficiency standards and prepare communities to deal with higher temperatures.
Obama raised climate change as a key second-term issue in his inaugural address in January, and in his State of the Union policy speech in February, he issued an ultimatum, saying "If Congress won't act soon to protect future generations, I will."