Tom Steyer, San Francisco hedge-fund billionaire and million-dollar donor to Democratic candidates -- including President Obama -- is something of a one-man Big Green with greater wealth and deeper contacts than many activist non-profit foundations.

He's waging a dogged end-of-the-world money war against fossil fuels and is currently cramming mega-bucks into a costly fight against the Keystone XL pipeline as a "game-over" environmental doomsday. Winning his fierce battle, however, won't do a thing about global warming, say climate researchers.

Ken Caldeira, climate researcher at the Carnegie Institution for Science in Stanford, Calif., told Nature Magazine in August: "I don't believe that whether the pipeline is built or not will have any detectable climate effect."

David Victor, a climate-policy expert at the University of California, San Diego, also told Nature, "As a serious strategy for dealing with climate, blocking Keystone is a waste of time. But as a strategy for arousing passion, it is dynamite."

Keystone XL arouses the rage of Steyer and less affluent Big Green activists because it would move unconventional thick bitumen, processed to flow easily, from Athabasca oil sands in Alberta, Canada, to U.S. refineries near the Gulf of Mexico.

The oil sands are dug out of the ground with big excavators, like a mine, and then processed on site for transfer to a refinery in a pipeline or by rail tank cars, like conventional oil.

The multi-step operation is seen as a carbon dioxide "monster" by former government scientist James Hansen. To the contrary, public polls show a majority of Americans favor construction.

But last Friday, the U.S. State Department's recommendation to proceed with the project was delayed until at least January by the agency's inspector general for an investigation.

Big Green activists claimed that ERM Group, which is writing the pipeline's supplemental environmental impact statement, has financial ties with TransCanada Corp., the pipeline's owner.

Tom Steyer founded Farallon Capital nearly three decades ago, and built much of its wealth on fossil-fuel investments. Steyer departed his firm last year to fight the "tar sands" -- as greenies snidely call them -- with a net worth estimated by Forbes at $1.4 billion.

Farallon has large holdings in Houston-based pipeline company Kinder Morgan, owner of the 60-year-old TransMountain Pipeline System, which transports processed oil sands with condensates from Edmonton, Alberta, to the seaport of Vancouver, British Columbia, for export to Asia.

Its $5.4 billion expansion program calls for an application late this year for government permits to carry more oil sands oil than Keystone.

Nobody is investigating Steyer for his financial ties to TransMountain and his pressuring Democratic contribution buddies -- including Obama in personal meetings -- to kill the competitor to Farallon's investment.

Sen. David Vitter, R-La., told Fox News, "who knows when he's going to divest of these investments. ... Maybe in a few months when his helping kill Keystone will boost them up to top value."

The leading pro-Keystone congressman, Rep. Lee Terry, R-Neb., introduced a bill to speed approval of the project that made it through the House on a 241-to-175 vote. Steyer's money in Democratic senators' pockets could influence votes. Obama has threatened a veto.

With a U.S. attack on Syria possibly in the offing, we may shortly see the OPEC countries retaliate with their oil weapon.

Terry spokesman Larry Farnsworth told me, "Americans are tired of being held hostage by this administration and OPEC. Energy independence is in reach, and now is the time to make it happen."

Washington Examiner columnist Ron Arnold is executive vice president of the Center for the Defense of Free Enterprise.