WASHINGTON U.S. Senator John Kerry's commitment to tackling global warming will face several tests if he takes over as secretary of state but stopping an issue that has become a top environmental focus - the Keystone XL pipeline - will likely not be among them.
President Barack Obama nominated Kerry on Friday for Hillary Clinton's job and the senator is expected to win swift Senate confirmation.
Kerry has been a dedicated, long-time campaigner for action on climate change. In 1992 he attended the first Rio Summit on climate, which formed the framework of U.N. climate talks. In 2010, he and Senator Joe Lieberman authored a sweeping climate bill that ultimately failed.
Kerry's wife, Theresa Heinz, champions environmental causes as chair of The Heinz Family Philanthropies, and Kerry has lectured on national security risks posed by climate upheaval - from the impacts of rising seas on military bases to severe heat on soldiers.
The approval of the TransCanada Corp's Keystone pipeline could be one of the first items the State Department will officially tackle if Kerry becomes secretary of state but he is unlikely to influence the decision.
Analysts say President Barack Obama already appears to have made up his mind on Keystone.
"We think that Obama has set the course on Keystone and it is still poised for approval sometime next year," said Divya Reddy, an analyst at the Eurasia Group, a political risk consultancy.
Unlike some senators, Kerry has not been outspoken against the pipeline, which will carry at least 700,000 barrels per day as it links Alberta's oil sands to refineries and ports in Texas. Environmentalists have battled the line because oil sands petroleum is more carbon intensive than average crudes refined in the United States.
The State Department is poised any day to release an environmental assessment of the project.
"Kerry could have more of an impact advancing the climate agenda in international talks, but it's hard to see how he can elevate the issue in a way that makes rejection of Keystone more likely," Reddy said.
Eileen Claussen, former assistant secretary of state for global environment issues and a former adviser to President Bill Clinton, said Kerry is well versed on climate issues and would soon confront tough questions.
Breaking gridlock with China on greenhouse gas emissions and working with the European Union to resolve disagreement over handling gases generated by airlines are just two, said Claussen, now president of the nonprofit Center for Climate and Energy Solutions.
In the case of China, Kerry's experience as chairman of the Senate Foreign Relations Committee could help him step beyond the U.N. climate talks framework and work bilaterally with the nation, which is the world's largest sources of greenhouse gases, she said.
The effort to reduce airline industry emissions, a U.N. initiative, also would come under Kerry's purview since the talks are partly led in Washington by the State Department.
Washington has long objected to EU plans to force all airlines to pay for the carbon emissions for flights into and out of Europe.
The EU announced earlier this month that it would suspend the law to allow the U.N.'s International Civil Aviation Organization to devise a global framework to curb emissions.
Kerry could help drive an agreement in those long-stalled talks, said Samuel Grausz, director of policy and research at advisory firm Climate Advisers.
But Kerry is unlikely to work miracles, Grauz said.
Claussen holds out hope Kerry will break ground with China, where demand for carbon-heavy coal is rising.
"If he strikes out and really deals with the Chinese, that's probably the most important climate issue there is."
(Editing by Marilyn W. Thompson and Bill Trott)