Sen. John Kerry (D-Mass.) testified before the Senate Foreign Relations Committee for his confirmation hearing for Secretary of State. (The Washington Post)

Calling himself “a passionate advocate” for energy policy, Sen. John Kerry said Thursday that climate change was among the top international threats facing the United States, cheering environmentalists and disappointing oil industry officials, who have been watching how his confirmation as secretary of state could affect the fate of the Keystone XL pipeline.

In his opening statement before the Senate Foreign Relations Committee, Kerry said that American foreign policy “is defined by life-threatening issues like climate change,” along with political unrest in Africa and human trafficking across the globe. Kerry, the panel’s outgoing chairman, has made the issue of global warming central to his career in public service. The Massachusetts Democrat has traveled repeatedly to international climate negotiations and pushed in the Senate — unsuccessfully — for a limit on national greenhouse gas emissions.

Later this year, the State Department must decide whether to grant TransCanada a presidential permit to build the 1,700-mile Keystone XL pipeline extension, which would carry heavy crude oil from Canada’s oil sands to America’s Gulf Coast refineries. Climate activists warn that the project would be devastating to the planet, while proponents say it would boost the nation’s energy security and generate short-term construction jobs.

Referring to the pipeline during the hearing, Kerry said that “it would not be long before it crosses my desk. But he did not offer his opinion on the project. He responded more forcefully, however, when Sen. John Barrasso (R-Wyo.) argued that stricter environmental regulations would harm the economy but have little impact on global climate.

“In this tight budget environment, with so many competing American priorities, I would ask you to give considerable thought into limiting significantly resources that would not help us as an economy, not help us as a country, and not help us globally in perhaps the efforts you might be pursuing,” Barrasso said.

Kerry shot back: “The solution to climate change is energy policy. You want to do business and do it well in America, we got to get into the energy race.” He cited California and his own state of Massachusetts as places where clean energy and energy efficiency are “growing faster than any other sector... This is a job creator.”

Noting that U.S. communities broke heat and fire records last year and suffered record-high damages from superstorm Sandy,” Kerry said: “If we can’t see the downside of spending that money and risking lives for all the changes that are taking place, to agriculture, to our communities, the ocean and so forth, we’re ignoring what science is telling us. So I will be a passionate advocate on this, but not based on ideology but based on facts, based on science.”

Environmentalists have put Kerry on notice that they expect him to use his new post to curb the nation’s carbon output, in part by rejecting TransCanada’s permit.

Erich Pica, president of the advocacy group Friends of the Earth, wrote in an e-mail Thursday morning that he agreed with Kerry’s opening remarks.

“As Secretary of State, he must elevate climate change to the highest echelons of a humane U.S. foreign policy, which is where this tremendous threat to human security should be placed,” Pica wrote. “Climate change has already begun to erode decades of development gains and create tremendous food insecurity, most especially in poorer countries; indeed, it poses a very real danger to the lives and livelihoods of many millions around the world. We would hope this means that, as a first point of action, Kerry would reject the Keystone XL pipeline.”

In recent meetings with State Department staff, the senator has said that President Obama has mandated that he focus on forging a bilateral climate agreement with China and work toward a pact on global warming to be finalized in the next few years and take effect in 2020, according to individuals who asked not to be identified because Kerry has not yet been confirmed.

Obama made the moral argument for addressing global warming in his second inaugural address on Tuesday, saying, “We will respond to the threat of climate change, knowing that the failure to do so would betray our children and future generations.”

Stephen Brown, vice president for federal relations at the oil refiner Tesoro Corp., said that the president’s and Kerry’s comments will make it hard for the administration to approve the pipeline. “If the White House ultimately approves the KXL extension, which I doubt, [White House press secretary] Jay Carney’s shop is going to have its work cut out reconciling that move with the recent, lofty rhetoric of the president and Department of State nominee Kerry on climate change,” he said.

Some members of Congress are already working to take advantage of Obama’s new emphasis on global warming. On Thursday, Rep. Henry Waxman (D-Calif.) and Sen. Sheldon Whitehouse (D-R.I.) announced they would form a bicameral task force on climate change.

“Carbon pollution is wreaking havoc on our atmosphere and on our oceans, and it’s time to bring all hands on deck as we seek to meet that challenge,” Whitehouse said in a statement.