LONDON (Reuters) - Changes to U.S. energy policies under new President Donald Trump are unlikely to have a big impact on global action to curb a rise in greenhouse gas emissions, oil major BP's (>> BP plc) chief economist said on Wednesday.

On Tuesday, Trump signed orders to smooth the path for the Keystone XL and Dakota Access oil pipelines in a move to expand energy infrastructure and roll back key Obama administration environmental decisions.

As part of his election campaign, Trump promised to bolster the U.S. oil, gas and coal industries, partly by undoing federal regulations curbing carbon dioxide emissions.

"The actual implications of change in U.S. policy are unlikely to be a big game changer," Spencer Dale, group chief economist at BP, told journalists in London.

"The U.S. has played an enormous leadership role together with China in galvanizing international support (for action on climate change) .... Much of that improvement in the outlook for carbon emissions isn't happening in America," he added.

"Improvements within America are due to energy efficiency ... which are still quite valued in an economy that encourages growth and competitiveness."

Earlier on Wednesday, the chief executive of German utility E.ON (>> E.ON SE) singled out the election of Trump as an obstacle to global efforts to tackle climate change.

China has been keen to be seen as leading the way on climate change as Trump has dismissed it as a "hoax" and vowed during his presidential campaign to pull the United States out of the 2015 Paris Agreement which aims to phase out net greenhouse gas emissions in the second half of this century.

"What could be a game changer is if the U.S. stops playing a significant (climate) leadership role, it then has significant implication for wider international commitment and that could have greater impact," Dale said.

In its annual Energy Outlook report on Wednesday, BP forecast renewable energy would be the fastest growing energy source to 2035, increasing at an average annual rate of 7.6 percent.

(Reporting by Ron Bousso and Nina Chestney; Editing by Mark Potter)

Stocks treated in this article : E.ON SE, BP plc