Eight years ago, Richard Branson, the tie-loathing adventurer (as his Twitter feed has it) and figurehead of Virgin Atlantic airlines, Virgin Galactic space travel and so on, pledged to invest around $3bn (£1.85bn) in green technologies by 2016. A $25m investment went into the Virgin Earth Challenge, a prize for inventing something to suck up all the planet-wrecking carbon emitted by gas-guzzling industries like his own. Some goes into developing low-carbon fuels. Some pays for the snazzy Carbon War Room, a sort of green-tech Dragons' Den. "Gaia capitalism", Branson has called his vision. "We have to make it a win-win for all concerned."

That 2016 deadline is fast approaching. How much, Naomi Klein asked Branson, will he have put into his pledge by then? "I suspect it will be less than $1bn right now," he confessed. He has been busy elsewhere in the meantime, launching Virgin America airlines, V Australia airlines, Virgin Atlantic Little Red airlines, and investing heavily in Virgin Galactic, perhaps because – as he has started saying – he has a plan to move to Mars. Klein doesn't necessarily follow the people who see Branson's green shenanigans as "a cynical ploy" to build his brand and confuse his critics. But you can grant him his good intentions and still think all this greenwash doesn't make a lot of sense.

There can be no doubt that climate change is happening; it has already started wreaking damage, and is set to do much more. Temperatures have risen by nearly 1C since the industrial revolution, and in 2012 the World Bank predicted a rise of 4C by 2100, bringing "extreme heat waves, declining global food stocks, loss of ecosystems and biodiversity and life‑threatening sea-level rise". And yet coordinated international response is completely missing. The 2009 Copenhagen climate summit settled for a half-hearted 2C target, then failed to secure commitment even on that. Obama seems stuck, as the US fracks and drills its heart out and Canada tears up Alberta in the race for tar. Climate, politics and business are caught in a vicious triangle, and at the moment it's the climate that is getting squeezed.

The only way to resolve this is with tough, fair, world-level regulation. But instead we have a vacuum, into which pours all manner of noxious nonsense. Climate-change deniers, luxuriantly astroturfed. Charities cosying up to fossil-fuel interests, including one, Klein has discovered, that has put oil and gas wells on its own bird reserve. Clever chaps who should know better – Stephen Hawking, the lads from Freakonomics – with their fantasies of terraforms and geo-engineering. Eddying little markets in non-solutions: carbon offsets, emissions trading, organic nappies. What's wrong with us that we've let this happen?

Klein argues that humans don't cause climate collapse, and nor does carbon. The problem is a particular arrangement of these elements – in other words, capitalism, the whole point of which is to find resources and exploit them. It's a habit of mind, if you like, a form of behaviour. As such, it can be changed. Except that most of the time we cannot see this, because we are "locked in, politically, physically and culturally" to the world that capital has made. "We lack the collective spaces in which to confront the raw terror of ecocide," is how Klein encapsulates the problem. Lucky for everybody then that opening up such spaces is exactly what Klein does best.

I'll never forget the interview with her in the Guardian after the publication of her first book, No Logo (1999). So quietly and sensibly you scarcely noticed, she completely shifted the terms of the anti-corporate argument, and the one about what politics in the 21st century is for. On her own development, from shopping addict to activist-intellectual: "The only way I got consumerism and vanity into a sane place in my life … was by becoming interested in other things." On why she won't judge you if your shoes were made in a sweatshop. "This is not a consumer issue, it's a political issue … Products are just stuff." Shopping or not shopping is neither here nor there: politics is about law and democratic structures. If politicians aren't doing what people think they should be doing, it's up to those people to find a way of getting them to change.

And yet, as The Shock Doctrine (2007) made plain, Klein also knows that what she's up against is extreme. Capital has learned lots recently about using disaster as a cash cow, from Katrina to Baghdad. "And there are plenty of signs that climate change will be no exception" is how she starts this book. Her task is to take a potential catastrophe of unimaginable reach and to be calm and welcoming, drawing new people in. She does vast amounts of travel and research and thinking, then crafts all of it to the scale of her own voice: the voice of a pleasant, funny, unthreatening-looking woman with layerings and lowlights, a husband and a baby, living in Toronto in what US Vogue, in its current issue, calls "a middle-class brick home". (You can access the Vogue piece from Klein's website, and it's worth reading. As are what Klein calls her "two issues" with it: that they mentioned her recent treatment for thyroid cancer, "not a subject I would have chosen to be public about", and that a promise was broken not to identify the brand of shirt she's wearing in the pictures – "Lots of people make nice white shirts.")

Capital, Klein argues, has been separating humans from the world around them since the discovery of steam. But it is what she calls "our great collective misfortune" that just as leaders started waking up to the emissions problem in the early 1990s, they were also establishing the World Trade Organisation, and with it, a "new era" of hyperactive deregulation, tax-cutting and privatisation of public space. When historians look back, as Klein says, they'll see the two processes in parallel, each pretending not to know about the other: the climate movement, "struggling, sputtering, failing utterly" and corporate globalisation, "zooming from victory to victory". The climate movement needs to think harder about capital, if it is to have a chance of getting real.

But it's difficult to spot climate change as it happens, because it moves so spasmodically and is by its nature "place-based". What do I know about the mines of Nauru or gas flares on the Niger Delta? What can I do about flooding in the Maldives or New Orleans? "Sacrifice zones" is what Klein chillingly calls the places most depredated: "Poor places. Out-of-the-way places. Places where residents lack political power, usually having to do with some combination of race, language and class." But even in the rich world, most people don't notice the dwindling of nature in their parks and gardens; or if they do, they are so sickened, they have to stop noticing right away. Which is why Klein sees the living wage as a climate issue. The main reason so many people are so careless is because they are worn out.

Her own eureka moment came, in 2009, she writes, over lunch with the Bolivian diplomat Angélica Navarro Llanos. "Using chopsticks as props," Navarro Llanos explained how tough international climate action might mobilise what she called "a Marshall Plan for the Earth". For the first time, Klein saw that climate change is not an abstract, sciencey matter, and that it's far too important to be left to the knit-your-owns. Her proposals for what she calls "a politics based on reconnection" involve real, ordinary, active humans, working in properly modern, complex societies. Green industries, such as renewable energy and public transport, are all much more labour-intensive than their fossil-fuel equivalents. "Climate action is in fact a massive job creator as well as a community builder and source of hope."

Klein hopes this book will be read by people who don't read climate-change books (such as me). So it's probably my duty to warn you that it is quite wordy, and sees things from a North American angle, and is a bit more vague about renewable energy than I'd like. But so what – it's an unavoidably difficult and complex subject. The argument is signposted throughout with striking buzzwords: Extractivism, Big Green, No Messiahs, Blockadia. Not to mention the brilliant title – an executive summary in itself.

There's one especially good bit, that completely stopped me dead. If you follow the climate science, you'll have heard the talk about how change doesn't happen incrementally but touches sudden "non-linear tipping elements", which may at any moment run completely out of control. Well, Klein also discusses a paper called "Is Earth Fucked?" by the geophysicist Brad Werner, which models the likely progress of "earth-human systems" towards various unpleasant outcomes, unless one remaining node of unpredictability is activated: "people or groups of people" who resist. Klein has timed her book to come out the week before the 2014 UN climate summit opens in New York City, and is on the board of 350.org, the group planning the People's Climate March that will greet it. We can only wish her and her fellow campaigners all the very best.

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