David Wallace-Wells used to shrug off climate change as just the price of economic growth, and then he didn’t any more.

A few years ago, I began collecting stories of climate change, many of them terrifying, gripping, uncanny narratives, with even the most small-scale sagas playing like fables: a group of Arctic scientists trapped when melting ice isolated their research centre on an island also populated by a group of polar bears; a Russian boy killed by anthrax released from a thawing reindeer carcass that had been trapped in permafrost for many decades. At first, it seemed the news was inventing a new genre of allegory. But of course climate change is not an allegory. Beginning in 2011, about a million Syrian refugees were unleashed on Europe by a civil war inflamed by climate change and drought; in a very real sense, much of the “populist moment” the west is passing through now is the result of panic produced by the shock of those migrants.

And that’s very alarming, because it’s not as if the trend is going to reverse itself. If we get racism and Trumps now what will it be like as the mass migrations get ever more mass?

The likely flooding of Bangladesh threatens to create 10 times as many, or more, received by a world that will be even further destabilised by climate chaos – and, one suspects, less receptive the browner those in need. And then there will be the refugees from sub-Saharan Africa, Latin America and the rest of south Asia – 140 million by 2050, the World Bank estimates, more than 10 times the Syrian crisis.

It wouldn’t go smoothly even if every single refugee were rich and lily-white.

Because these numbers are so small, we tend to trivialise the differences between them – one, two, four, five. But, as with world wars or recurrences of cancer, you don’t want to see even one. At 2C, the ice sheets will begin their collapse, bringing, over centuries, 50 metres of sea-level rise. An additional 400 million people will suffer from water scarcity, major cities in the equatorial band of the planet will become unlivable, and even in the northern latitudes heatwaves will kill thousands each summer. There would be 32 times as many extreme heatwaves in India, and each would last five times as long, exposing 93 times more people. This is our best-case scenario. At 3C, southern Europe would be in permanent drought, and the average drought in Central America would last 19 months longer. In northern Africa, the figure is 60 months longer: five years. At 4C, there would be 8m more cases of dengue fever each year in Latin America alone and close to annual global food crises. Damages from river flooding would grow thirtyfold in Bangladesh, twentyfold in India, and as much as sixtyfold in the UK. Globally, damages from climate-driven natural disasters could pass $600tn – more than twice the wealth that exists in the world today. Conflict and warfare could double.

But it’s all in the future…except when it’s not.

The California fires of 2017 burned the state’s wine crop, blowtorched million-dollar vacation properties, and threatened both the Getty Museum and Rupert Murdoch’s Bel-Air estate. There may not be two better symbols of the imperiousness of American money than those two structures. Nearby Disneyland was quickly canopied by an eerily apocalyptic orange sky. On local golf courses, the west coast’s wealthy swung their clubs just yards from blazing fires in photographs that could not have been more perfectly staged to skewer the country’s indifferent plutocracy. Last year, Americans watched the Kardashians evacuate via Instagram stories, then read about the private firefighting forces they employed, the rest of the state reliant on a public force full of conscripted convicts earning as little as a dollar a day.

And the fires are not only the effects of warming, they also add to it.

When trees die – by natural processes, by fire, at the hands of humans – they release into the atmosphere the carbon stored within them, sometimes for as long as centuries. In this way, they are like coal. This is why the effect of wildfires on emissions is among the most feared climate feedback loops – that the world’s forests, which have typically been carbon sinks, would become carbon sources, unleashing all that stored gas. The impact can be especially dramatic when the fires ravage forests arising out of peat. Peatland fires in Indonesia in 1997, for instance, released up to 2.6 gigatons (Gt) of carbon – 40% of the average annual global emissions level. And more burning only means more warming only means more burning. Wildfires make a mockery of the technocratic approach to emissions reduction.

In the Amazon, 100,000 fires were found to be burning in 2017. At present, its trees take in a quarter of all the carbon absorbed by the planet’s forests each year. But in 2018, Jair Bolsonaro was elected president of Brazil, promising to open the rainforest to development – which is to say, deforestation. How much damage can one person do to the planet? A group of Brazilian scientists has estimated that between 2021 and 2030, Bolsonaro’s deforestation would release the equivalent of 13.12 Gt of carbon. In 2017, the US, with all of its aeroplanes and automobiles and coal plants, emitted about 5 Gt.

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