The former head of the US Geological Survey (USGS), now editor-in-chief of Science magazine, has endorsed building a pipeline to transport crude oil from Canada's oil sands to the United States.
Marcia McNutt argued in the magazine that if the Keystone XL pipeline were not built, the oil would be carried by rail and road tankers, which would be more environmentally damaging.
McNutt, who headed the USGS from 2009 until last year and also served as the US Interior Department's senior science adviser, wrote in an editorial, "I believe it is time to move forward on the Keystone XL pipeline" in exchange for getting Canadian officials to reduce their oil industry's carbon emissions.
One of the primary objections environmentalists have raised against the project is that it would accelerate global warming because of the high amount of energy needed to extract oil from the deposits in Alberta.
McNutt is the latest former Obama administration official to come out in favour of the pipeline in recent weeks. Former interior secretary Ken Salazar said on February 5 that he thought the administration should approve the project, which would transport oil to refineries on the US Gulf coast.
The idea of Canada compensating for the pipeline's climate impact has been publicly contemplated for months, but neither Canadian nor American officials have ever specified what policies would satisfy the Obama administration.
US President Barack Obama has repeatedly raised the prospect of collaborating with Canada on carbon reductions when discussing the pipeline.
In an interview with The New York Times in July, the president said Canada could "potentially be doing more to mitigate carbon release", but added: "We haven't seen specific ideas or plans."
On Wednesday, after meeting Canadian Prime Minister Stephen Harper as part of a North American leaders' summit in Mexico, Obama said they "discussed a shared interest of working together around greenhouse gas emissions".
He added that the issue of climate change "has to affect all of our decisions at this stage" regarding Keystone XL. "So I welcome the work that we can do together with Canada."
In an interview this month, Canada's ambassador to the US, Gary Doer, said his country was "open to moving ahead" on climate change, including when it comes to the oil and gas industry. He said Canada would not adopt more stringent rules on oil and gas than those in the US.
Doer said Canada was already pushing to phase out coal-fired power plants and that Alberta had a limited carbon tax. Emissions from oil sands projects have pushed Canada's greenhouse gas emissions above the target it agreed to under the Kyoto Protocol in 1997.
When asked whether the United States had broached the idea of Canada offering a new climate initiative as part of the discussion over the Keystone pipeline, a State Department official who asked not to be identified to discuss the decision making said; "There is no quid pro quo."
In the Science editorial, McNutt argues that while she has sought to reduce her personal use of fossil fuels, she has become convinced that Alberta's heavy oil deposits would be extracted and exported because "truck and rail transports are viable alternatives to a pipeline between Canada and the US".