A former head of the U.S. Geological Survey endorsed the idea of building the Keystone XL pipeline Thursday in an editorial contending that the pipeline would be less damaging to the environment than the “viable alternatives” of transporting oil by rail and truck .

Marcia McNutt, who headed the USGS from 2009 to 2013 and now serves as editor in chief of the journal Science, wrote in the editorial, “I believe it is time to move forward on the Keystone XL pipeline.” She said approval of the project could be made conditional on Canada’s agreeing to reduce its oil industry’s carbon emissions.

McNutt, who also served as the Interior Department’s senior science adviser, is the latest former Obama administration official to come out in favor of the pipeline in recent weeks. Former interior secretary Ken Salazar said Feb. 5 that he thought the administration should approve the project, which would transport oil from Canada’s oil sands region to refineries on the U.S. Gulf Coast.

The idea of having Canada compensate for the pipeline’s climate impact has been publicly contemplated for months, but neither Canadian nor American officials have suggested specific policies that might satisfy the Obama administration.

One of environmentalists’ primary objections to 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.

Map of the Keystone XL pipeline.

President Obama has repeatedly raised the prospect of collaborating with Canada on carbon reductions when discussing the pipeline.

In a July interview with the New York Times, Obama said Canada could “potentially be doing more to mitigate carbon release,” but he remarked in the same interview, “We haven’t seen specific ideas or plans.”

On Wednesday, after meeting with Canada’s prime minister, Stephen Harper, as part of a North American summit in Mexico, Obama told reporters that they had “discussed a shared interest of working together around greenhouse gas emissions.”

He said the issue of climate change “has to affect all of our decisions at this stage” concerning Keystone XL. “So I welcome the work that we can do together with Canada.”

In an interview this month, Canada’s ambassador to the United States, Gary Doer, said his country was “open to moving ahead” on climate change, including decisions affecting the oil and gas industry. But he said Canada would not adopt industry rules that are more stringent than those in the United States.

“We don’t want our rule on operations in British Columbia to be one way when you’re going to have others in Pennsylvania,” Doer said, noting that the oil ends up competing on the same market.

Doer said that Canada is pushing to phase out coal-fired power plants and that Alberta has a limited carbon tax. But emissions from processing the oil sands have pushed Canada’s greenhouse gas emissions well above the target it agreed to under the Kyoto Protocol in 1997.

A State Department official was asked whether the United States had broached the idea of a new Canadian climate initiative as part of the discussion of the Keystone pipeline. The official, who asked not to be identified while commenting on the decision-making process, said, “There is no quid pro quo.”

In the Science editorial, McNutt remarked that she has sought to reduce her personal use of fossil fuels. But she wrote that she has become convinced that Alberta’s heavy crude deposits will be extracted and exported in any case because “truck and rail transports are viable alternatives to a pipeline between Canada and the United States.”

She suggests that “President Obama, who has yet to decide on the pipeline, could put conditions on approval that require Canadian authorities to reduce the carbon intensity of extracting the tar from the oil sands and processing it into a liquid petroleum product.”

“As part of a compromise to allow the project to move forward, let’s now insist on an income stream from Keystone XL revenues to support investment in renewable energy sources to secure our energy future,” McNutt wrote.

The timing of the administration’s decision on the project remains uncertain, especially after a Nebraska judge on Wednesday struck down a state law allowing Gov. Dave Heineman (R) to approve the pipeline’s route through the state.