NEW YORK (AP) -- A controversial oil pipeline to the U.S. Gulf Coast "absolutely needs to go ahead," Canada's prime minister said Thursday, and he warned that the oil will be transported through America one way or another.
Stephen Harper addressed the Keystone XL project, a flashpoint in the debate over climate change, during a visit to New York City. The long-delayed project carrying oil from Canada's tar sands would need approval from the State Department, and Harper's remarks — with the U.S. ambassador to Canada, David Jacobson, in the audience — were meant to apply some pressure.
"The only real immediate environmental issue here is, do we want to increase the flow of oil from Canada by pipeline or via rail?" Harper said. He called railroad transit "far more environmentally challenging."
Dozens of protesters from groups including the Sierra Club chanted against the pipeline as Harper arrived at the Council on Foreign Relations.
The Obama administration is considering whether to approve the pipeline, which would carry 800,000 barrels of oil a day from Alberta across six U.S. states to the Texas Gulf Coast. A decision is expected this summer.
Republicans, and business and labor groups, have urged the Obama administration to approve the pipeline as a source of much-needed jobs and a step toward North American energy independence.
Environmental groups have been pressuring President Barack Obama to reject the pipeline, saying it would carry "dirty oil" that contributes to global warming. They also worry about a spill.
Obama's initial rejection of the pipeline last year went over badly in Canada, which relies on the U.S. for 97 percent of its energy exports.
The pipeline is critical to Canada, which needs infrastructure in place to export its growing oil sands production. The northern Alberta region has the world's third largest oil reserves, with 170 billion barrels of proven reserves.
John Manley, a former Canadian foreign minister who is now head of the Canadian Council of Chief Executives, said if Keystone XL is rejected the relationship between the Harper government and the Obama administration would be irreparably harmed.
"It would be really hard to recover from this," Manley said. "It would be quite a blow to the relationship."
A lack of pipelines and a bottleneck of oil in the U.S. Midwest have reduced the price of Canadian crude, costing oil producers and the federal and Alberta governments billions in revenue.
"I think all the facts are overwhelmingly on the side of approval of this," Harper said Thursday. He added that climate-affecting emissions from oil sands are "almost nothing globally."
Anticipating such comments, the National Resources Defense Council on Thursday announced a new Tar Sands Reality Check campaign that it launched with other environmental groups.
"Prime Minister Harper's appeal to the U.S. won't change the fact that the science has shown again and again that producing tar sands oil is much more greenhouse gas intensive than conventional oil," the NDRC's Canada director, Danielle Droitsch, wrote in a blog post Thursday.
Keith Stewart of Greenpeace Canada added in a blog post Thursday: "Rail can't replace pipelines — at least not anytime soon or without massive new rail infrastructure."
Harper seemed to dismiss the environmental protesters during comments about climate change.
"It is not a matter of just getting on a street corner and just yelling and that will somehow lead to a solution," he said.
TransCanada spokesman Shawn Howard in a statement Thursday that Harper's advocacy "helps cut through the noise and misinformation about the project. He clearly understands the importance of this project for Canada." TransCanada Corp. is now looking at a mid to late-2015 start-up for the pipeline project.
Harper's wide-ranging comments also touched on Syria and Israel.
"There's nothing more shortsighted in Western capitals in our time than the softening of support we've seen for Israel around the globe," he said, calling the country "the one stable, democratic ally in this part of the world."
On Syria, Harper urged "extraordinary caution" on the idea of arming the opposition.
"We should not fool ourselves about what's happening in Syria," he said, saying there is "brutality and extremism on both sides."
"To start talking about arming unnamed people whose objectives we don't understand, I think, is extremely risky," Harper said.
Associated Press writer Rob Gillies in Toronto contributed to this report.