“Every inhabitant of this planet must contemplate the day when this planet may no longer be habitable.” Thus spoke President Kennedy in a 1961 address to the United Nations. The threat he warned of was not climate chaos — barely a blip on anybody’s radar at the time — but the hydrogen bomb. The nuclear threat had a volatile urgency and visual clarity that the sprawling, hydra-headed menace of today’s climate calamity cannot match. How can we rouse citizens and governments to act for concerted change? Will it take, as Naomi Klein insists, nothing less than a Marshall Plan for Earth?

“This Changes Everything: Capitalism vs. the Climate” is a book of such ambition and consequence that it is almost unreviewable. Klein’s fans will recognize her method from her prior books, “No Logo: Taking Aim at the Brand Bullies” (1999) and “The Shock Doctrine: The Rise of Disaster Capitalism” (2007), which, with her latest, form an antiglobalization trilogy. Her strategy is to take a scourge — brand-­driven hyperconsumption, corporate exploitation of disaster-struck communities, or “the fiction of perpetual growth on a finite planet” — trace its origins, then chart a course of liberation. In each book she arrives at some semihopeful place, where activists are reaffirming embattled civic values.

To call “This Changes Everything” environmental is to limit Klein’s considerable agenda. “There is still time to avoid catastrophic warming,” she contends, “but not within the rules of capitalism as they are currently constructed. Which is surely the best argument there has ever been for changing those rules.” On the green left, many share Klein’s sentiments. George Monbiot, a columnist for The Guardian, recently lamented that even though “the claims of market fundamentalism have been disproven as dramatically as those of state communism, somehow this zombie ideology staggers on.” Klein, Monbiot and Bill McKibben all insist that we cannot avert the ecological disaster that confronts us without loosening the grip of that superannuated zombie ideology.

That philosophy — ­neoliberalism — promotes a high-consumption, ­carbon-hungry system. Neoliberalism has encouraged mega-mergers, trade agreements hostile to environmental and labor regulations, and global hypermobility, enabling a corporation like Exxon to make, as McKibben has noted, “more money last year than any company in the history of money.” Their outsize power mangles the democratic process. Yet the carbon giants continue to reap $600 billion in annual subsidies from public coffers, not to speak of a greater subsidy: the right, in Klein’s words, to treat the atmosphere as a “waste dump.”