Doerr regularly trots out chum Al Gore to run through his Inconvenient Truth slide show in front of influential audiences of businesspeople and politicians. He makes regular appearances on public television’s Charlie Rose Show and has also drawn criticism for overhyping global warming—even from greentech fans.

On one episode of Charlie Rose last year, Doerr sounded grave: “The latest fear from scientists at Caltech is not that Greenland will melt but that it’s going to slip off the rocks.… If we lose Greenland, all the scientists agree that oceans will rise by 20, 30 feet. That puts downtown Manhattan underwater. That means where we are in Silicon Valley will be underwater. We will lose most of Mumbai in India.”

Quite alarming—until you discuss the topic with Caltech’s Eric Rignot, senior research scientist at the institute’s Jet Propulsion Laboratory. In an email, he offers his reaction to Doerr’s scenario: “This is certainly excessive, only the extremist part of the story. In all likelihood, Greenland will contribute one foot of sea level rise by 2100. If the climate warms very fast and all glaciers go mad, it could go up 10 feet. And then if you melt every bit of ice down to the ground, it would reach 20 feet. But even that did not happen in the last interglacial. This is a most extremist scenario.”

Doerr credits his teenage daughter with deepening his commitment to greentech. During an after-dinner conversation with friends last year, the subject of global warming arose. She piped up, “Dad, I’m scared and angry. Your generation created this problem. What are you going to do to fix it?”

What he is doing is steering at least $200 million to greentech startups, 15 of them so far. They include Altra, a builder of ethanol refineries; Amyris Biotechnologies, which is using a technique for making antimalaria drugs to convert materials including switchgrass and cornstalks into biofuel; Miasolé, a company that makes sheets of film that can be used in roofing material as affordable solar devices; Lilliputian Systems, which is engineering small fuel cells for handheld computers and cell phones; GreatPoint Energy, which is attempting to make coal gasification more efficient; and Bloom Energy, a company developing solid oxide regenerative fuel cells.

Doerr, who sits in Kleiner Perkins’ Menlo Park conference room discussing greentech, is wearing a gray button-down shirt and khakis. He’s always in motion, jiggling his legs, pinching his nose, running his fingertips along his jaw. Asked how he justifies his push for increased government subsidies, he inexplicably lifts his left arm toward the ceiling to reveal a red Indian-bead bracelet. He lets his hand fall, drops his elbows to the table, puts both hands on his face, and finally blurts, “I’m a raging capitalist!”

Happy with his setup line, he continues, “Markets are incredibly important, but they’re not perfect.” To get greentech kick-started, he argues, subsidies and mandates should be acceptable, as long as “you don’t overuse them and proceed in a bipartisan manner.”

Doerr jumped into politics in 1996, incensed by a California ballot proposition that would have left tech startups more vulnerable to class action suits. He helped organize Valley business leaders and defeat it, then channeled that momentum into creating Technet, a pro-technology lobbying group.

More victories followed. Education was an early priority, and Technet helped pass a ballot initiative in 2000 to aid charter schools; John and Ann Doerr personally contributed $8.7 million to the campaign. In 2004, California voters agreed to spend $3 billion to fund stem cell research in the state, a poke in the eye for President Bush and a boon to the Valley’s biotechnology industry. The biggest contribution came from the Doerrs: $6 million.