Bill McKibben, a writer for The New Yorker, has emerged as the leader of the popular movement to get us to give up fossil fuels. He is the founder of 350.org, which is intent on returning the amount of carbon dioxide in the atmosphere to 350 parts per million (it just passed 400).

McKibben has written more than a dozen books, including The End of Nature and most recently Oil and Money. His organization 350.org has sponsored 20,000 demonstrations around the world in every country except North Korea. He spearheaded the opposition to the Keystone Pipeline and spent three days in jail in Washington after leading a demonstration. He was recently rewarded when President Obama cancelled the project. For his efforts he has been awarded the Right Livelihood Prize, sometimes called the “alternative Nobel.”

Recently he has turned to a new tactic – suing ExxonMobil for allegedly covering up their knowledge of global warming in the 1970s. Keying on reporting at the Los Angeles Times and Inside Climate News McKibben and others have latched on to the story that someone at ExxonMobil observed that excessive burning of fossil fuels might eventually warm the climate but the oil company did nothing about it. Senator Sheldon Whitehouse of Rhode Island wants all climate deniers charged with racketeering. Of course all this assumes that the public would have reacted to the news any differently in 1975 than they have now. (Less than half the public believes global warming is a “very serious” problem.) But to McKibben, the press and liberal politicians it’s all part of one big conspiracy with a big rich oil company pulling the strings behind the scene. As McKibben told Rolling Stone:

Exxon is, beyond any shadow of a doubt, morally and practically culpable for failing to speak up when they should have done so and could have saved the world a wasted quarter century. They helped waste what may turn out to be the most critical quarter century in human history.

Now here’s an interesting story about Bill McKibben. I did a brief interview with him four years ago when he was just beginning his crusade for 350.org. The occasion was the Vermont “Solarfest,” an event held on a farm in rural Vermont every July. About 150 young enthusiasts camped on a hillside for several days, some selling wares or gathering petitions and all advertising the wonders of solar energy. Scattered in among them, however, were people also crusading for the closing of the Vermont Yankee nuclear reactor. They constituted about half the crowd.

After McKibben gave his rousing speech to an enthusiastic audience, I was able to grab him for a moment in back of the little makeshift stage. I asked him about nuclear power. He admitted that nuclear was going to be necessary if we were ever to reduce the amount of carbon in the atmosphere. “Why don’t you come out favorably in public for nuclear power, then?” I asked. He surveyed the hillside, almost half the people crusading against Vermont Yankee. “If I came out in favor of nuclear,” he said, “it would split this movement in half.”

So there you have it. McKibben, like many other environmentalists, knows in his heart that there isn’t much chance of reducing carbon output without nuclear. But he does not want to be caught saying so in public.

Now let’s look at what’s happened since then. Two years later, the Entergy Corporation gave in to nuclear protesters and decided to close Vermont Yankee. The reactor provided two-thirds of the state’s electricity and made it the lowest carbon generating jurisdiction in the country. Now Vermont is burning natural gas and importing some of its electricity from New York’s Indian Point reactors which are located on the lower Hudson River just north of New York City.

But that isn’t the end. Entergy is now planning to close the Pilgrim reactor, which provides eastern Massachusetts with carbon-free energy. In California, San Diego Electric was dragooned into closing the twin San Onofre reactors, a decision that threw 8 million tons of replacement carbon into the atmosphere – the equivalent of 1.6 million cars – and increased the state’s emissions by 35 percent. Now Entergy has announced it will also close the Fitzpatrick reactor in upstate New York – a move that has upset New York Governor Andrew Cuomo even though he has spent most of his time in office trying to close down Indian Point.

The explanation of all this is that nuclear can’t compete with cheap natural gas, but that is not really true. What cripples nuclear is that it receives absolutely no credit for generating electricity without producing any carbon emissions. Despite all the yammering about cutting carbon, nuclear gets absolutely no advantage, financial or otherwise, for being a zero-carbon source. This has been reinforced by President Obama’s Clean Power Plan, which gives states no credit for having carbon-free nuclear on their grid but only allows credit for newly constructed nuclear – as if anyone is ever going to get a permit for a new reactor past the Nuclear Regulatory Commission.

Being an environmentalist who favors nuclear is in fact not without its risks. You may recall the Audubon Society being active in the anti-nuclear movement around the time of Three Mile Island. Their spokesman was a Princeton nuclear physicist named Jan Beyea, who at one point appeared on William F. Buckley’s “Firing Line.” In the 1990s, when the Clinton Administration was trying to shut down nuclear entirely Beyea made an offhand remark that the government should at least continue to fund nuclear research. That remark caused Audubon to lose one-third of its funding and cost Beyea his job. Audubon quit energy altogether and went back to trying to protect birds from windmills.

In Canada last week a British Columbia man was arrested for making death threats against Professor Jay Cullen of Victoria University. Cullen had written a paper disputing the assertion that all the ocean life in the Pacific has been contaminated by radioactive fallout from Fukushima. Dana Dumford was charged with two counts of criminal harassment after posting a YouTube video calling for Professor Cullen’s death.

So it isn’t as if being an environmentalist who supports nuclear is completely free of dangers. Still, if McKibben and others have been willing to brave jail in order to halt Keystone, they shouldn’t be afraid to come out of the closet on nuclear. And if indeed McKibben and other environmental leaders have been deliberately hiding their views on nuclear while so much new carbon is dumped into the atmosphere, shouldn’t some ambitious attorney general charge them with conspiracy for keeping their support a secret during this most important quarter century in human history?