Tom Clancy is one of my favorite writers. His books are thrillers with very detailed technological and geopolitical themes.

We all know his novels: “Hunt for Red October,” “Red Storm Rising,” “Patriot Games,” “Cardinal of the Kremlin,” “Clear and Present Danger,” “The Sum of All Fears,” “Without Remorse,” “Debt of Honor,” “Executive Orders,” and “Rainbow Six.”

I just finished “Rainbow Six.” Like all Clancy novels, it is fiction with a compelling factual basis. Clancy is a master who weaves many storylines into one central plot. More importantly, however, what he fictionalizes is totally plausible. When you read his novels, you come away with the chilling notion: It could happen. Probably his most convincing novel for me before “Rainbow Six” was “The Sum of All Fears.” It is a techno-thriller about Third World terrorists who get their hands on nuclear material to plant a nuclear bomb outside the Super Bowl game in Denver. Guess what flashed across my mind when the lights went out in the Super Dome in New Orleans recently?

“Rainbow Six” has all the military and spy elements that make a Clancy novel hard to put down. There is the team of anti-terrorists who can shoot off the head of a pin or the head of a terrorist from 200 yards. There are old Russian KGB spies and aging terrorists reverting to their old ways with chilling consequences.

However, the main plot centers around an eco-terrorism conspiracy to kill most of people in the world to “save the planet.” It is pretty far-fetched and a bit hard to identify with the plots in other Clancy novels. It seems a little out of character for Clancy. Nevertheless, Clancy captured me once again with his craftsmanship, and I hurried through the pages to get to the end, which never fails to totally surprise. You’ll have to read how the good guys took care of the bad guy eco-terrorists. It’s so fitting.

Even when I finished the book, I still had a difficult time accepting even the remote believability of anyone killing most of the people on the planet to save it.

Shortly after that I went to the California Weed Science Society annual meeting where I was asked to speak on the history of Roundup Ready alfalfa and my “fondness” for environmental whackos, comparing them to those who protested smallpox and polio vaccines. In talking to people afterward who have encountered similar disturbed environmental whackos, it made Clancy’s eco-terrorism plot seem plausible.

A friend talked about how he has seen starving children in impoverished nations who could be helped by advancement in biotechnology, yet environmentalists object to the technology and ignore the needs of millions of hungry people. It convinced me there are radical environmentalists who are willing to put plants and animals ahead of people, as difficult as that is to swallow. Not all the so-called environmentalists are that demented.

Clancy’s eco-terrorism thriller is unsettling, but it puts into perspective the thinking of the truly radical in the environmental movement, and serves as fair warning to guard against the motives of hopefully only a few.