There is a reason that the autobiographies of eminent men usually go unread. Ponderous, long, and endlessly self-justifying, they aim at settling scores, at revenging slights, and at securing the much-desired Place in History. Though Gus Speth is decidedly eminent—possessor as he himself admits of an unparalleled resume—he is the precise opposite of pompous. His memoir is almost too short, and much of it is devoted to making the case that accidents of time and place helped make his career.

The first of those was his birth in Orangeburg, South Carolina, in 1942—that is, into the Jim Crow Deep South. A fairly idyllic boyhood (which includes meeting the woman in pre-school with whom he will this year celebrate his 50th anniversary) was brought into different focus when he journeyed north to Yale in 1960, and there began to find a new perspective on the world he’d grown up in. His school years were devoted in large measure to studying the political culture of the South, and looking for some way to square it with his emerging sense of justice. He ended up trying unsuccessfully to organize his state’s Democrats for Gene McCarthy in 1968, in the process deciding that his “views had become too detached from my Carolina roots and drifted too far left to allow a political career” there.

The Palmetto State’s loss was the nation’s gain. A young law school graduate, he helped found the Natural Resources Defense Council, which went on to become the most important legal advocate for the environment in the years after the first Earth Day, when American environmentalism was on the ascent. They rarely lost in court, and his effective insider advocacy propelled him to the chairmanship of Jimmy Carter’s Council on Environmental Quality, as well as a key role in the Clinton administration and a job as the head of the United Nations Development Program. Along the way he also made time to found the World Resources Institute, and to serve as dean of Yale’s premier School of Forestry and the Environment. In other words, more than any other person, perhaps, he built the “pragmatic and incrementalist” environmentalism that we know today, with its strong focus on inside-the-Beltway lobbying and courtroom pleading.

That environmentalism gave America clean air and clean water, which are great victories sufficient for any movement. We can swim in most of our rivers and breathe in most of our cities. But that movement has so far proved utterly unable to slow the rise of the planet’s temperature—a crisis so severe and far-reaching that, unabated, it will wipe out all the gains of the past four decades.

To solve that crisis, writes Speth, we need to forget much of the way we’ve practiced environmentalism, and build anew the kind of movement that gave the cause its great spark at the first Earth Day. “America has run a 40-year experiment on whether mainstream environmentalism can succeed, and the results are now in.” Along with—more than—the inside lobbying, we need “a huge, complementary investment of time, energy, and money in other, deeper approaches to change.” His new environmentalism would realize that corporate power, runaway consumerism, and the insane divide between rich and poor are all driving global warming, and that dealing with the environment inevitably means addressing inequality, race, and the generalized corruption of our politics. “The final goal of the new environmental politics must be, ‘Build the movement.’”

That is a hard struggle, and one whose outcome is far from certain. Speth has watched in sadness as the politics of the Deep South have spread out to become the politics of a nation (“it now appears that the South has not only risen but has colonized great swaths of the American mind in the process”). But he’s also played a large role in the rise of the new movement challenging that entrenched power and mindset. Among other things, the man with the golden resume went to jail in 2011 to protest the Keystone Pipeline, spending a few nights in the D.C. clink to help launch what became an unlikely but nonetheless pitched battle with the fossil fuel industry. (“I’ve held many influential positions in this town, but none seem as important as the one I’m in right now,” he told reporters from behind bars.)

One wishes Speth the happiest of retirements—he and his wife Cameron live in rural Vermont, where they rediscovered the agrarian values and community sense of their southern upbringing, this time hitched to the progressive politics and tight community of the Green Mountain State. But one also counts on Speth to add some more lines to his CV before the fight is over. There is almost no one with more perspective on where we’ve come from, and where we need to go.