Not​ all deaths are created equal. In February 2020, the world began to panic about the novel coronavirus, which killed 2714 people that month. This made the news. In the same month, around 800,000 people died from the effects of air pollution. That didn’t. Novelty counts for a lot. At the start of the pandemic, it was considered unseemly to make comparisons like these. But comparing the value of human lives is one thing the machine of modern civilisation does relentlessly, almost invariably to prioritise and absolve the rich – when, for example, the global supply of Covid vaccines is apportioned primarily to the highest-income countries, or when the cost of natural disasters in Bangladesh is measured against the impact of sea-level rise on Miami Beach real estate, or when Joe Biden’s onetime economic adviser Lawrence Summers proposed that Africa, as a whole, was ‘vastly underpolluted’, and suggested that ‘the economic logic behind dumping a whole load of toxic waste in the lowest wage country is impeccable.’

In its first year, the pandemic did damage according to the opposite logic, with the world’s wealthiest countries the worst hit. When people in those countries tried to diminish the threat of the virus by comparing it to the flu, the disease made a joke of them. But air pollution kills more than ten times as many as the flu every single year, and we hear even less about it. In 2017, a Lancet study put the figure at almost seven million a year, about two-thirds from outside air pollution and one-third from indoor, household pollution. More recent estimates run higher, with as many as 8.7 million deaths every year attributable just to the outdoor particulate matter produced from burning fossil fuels. Add on indoor pollution, and you get an annual toll of more than ten million. That’s more than four times the official worldwide death toll from Covid last year. It’s about twenty times as many as the current annual deaths from war, murder and terrorism combined. Put another way, air pollution kills twenty thousand on an average day, more than have died in the aftermath of all the meltdowns in the history of nuclear power: Chernobyl, Three Mile Island, Fukushima and all the others put together. If the pandemic so terrified us that billions of us retreated into panicked cocoons for months, what can explain or justify our blindness and indifference towards the ten million lives ended each year by the repeated inhalation of smog?

Ten million deaths a year is a hundred million a decade. The numbers are so large that even the superlatives of disaster fail. They’re so large that they strain credulity, perhaps partly because none of us can picture someone dying in the street from air pollution and partly because it seems pathetically old-fashioned for a doctor to advise a sojourn in healthier air. But the chances are that you can’t picture a death from obesity or cigarette smoking either, and yet you probably don’t doubt estimates of their toll on human wellbeing, or think it wrong to call Louisiana’s River Parishes ‘Cancer Alley’ – the presence of 150 petrochemical plants has made it an incontrovertibly unhealthy place to live, with some communities registering cancer rates fifty times the national average. Such areas are sometimes known as ‘sacrifice zones’.

A single speck of black carbon, inhaled, won’t stop the heart or poison the lungs, but over time, across populations, the effect is devastating. When we talk about death we always want to see a murderer. When there isn’t one, it’s a lot harder to call it a murder, rather than a tragedy or an act of God. (‘You see one person run over in the street and you’ll never forget it,’ an environmentalist observes in Choked: The Age of Air Pollution and the Fight for a Cleaner Future.* Thousands dying from the effects of dirty air ‘will never even faze you’.) But the central premise of any mortality model is that everyone dies: the question is when, and whether a certain behaviour or environmental factor hastened that end. And while none of these estimates is meant to suggest a single cause of mortality, such as a gunshot wound or a dose of poison in your morning tea, the calculus for air pollution is the same as for obesity or smoking: take the problem away, and the number of premature deaths will fall by many millions. According to new research, half of these deaths, concentrated in the developing world, are the result of consumption and fossil-fuel burning in the world’s richest countries.

The environmental historian Stephen Pyne calls our era the ‘pyrocene’, a global regime of burning: coal and oil, agricultural land and forest, bush and wetland, most of it planned. The Anthropocene, Pyne says, implies dominion over nature. He prefers to emphasise the fact that, wherever you look, the earth is in flames. The residue is carbon monoxide, nitrogen dioxide, ozone, black carbon, sulphur dioxide, and the particularly toxic grouping of small particulate matter known as PM2.5. Everything we burn, we breathe.

Hundreds of millions of people live and breathe in cities permanently clouded by airborne toxic events. In November, the authorities in Delhi closed schools and colleges indefinitely, suspended construction work, and shuttered half of the local coal plants after an episode of ‘toxic smog’ and an order from the Indian Supreme Court to institute emergency measures to combat it. The smog wasn’t new; the response was. Throughout the city, particulate matter hangs around in offices, lobbies and private homes, even those with air purifiers. It often gets so thick that it interferes with air travel. More remarkably, it has interrupted train travel, the smog making it impossible for drivers to see the tracks. Taxi drivers have filtration systems to process the particulates that sneak in. Pedestrians can’t escape it, which is one reason that, on especially smoggy days, living in Delhi is the equivalent of smoking several packets of cigarettes. The city has the highest rates of respiratory illness in the world, and 60 per cent of inhabitants diagnosed with COPD – chronic obstructive pulmonary disease – aren’t even smokers.

Across India as a whole, where more than a million people die from air pollution each year, exposure to small particulate matter has been estimated at five times the World Health Organisation’s longtime ‘safe’ level – defined as ten micrograms per cubic metre of air. This year the WHO set a new standard, at half the old level. Under the old threshold, 90 per cent of the world’s population were breathing dangerously polluted air; under the new threshold the figure is closer to 99 per cent. Of the world’s fourteen most polluted metropolises, only one (Hotan in China) is outside India. Of the 336 cities that come next on the list, 184 are in China. But this isn’t to say that air pollution is a problem in just two countries. Globally, it causes one death in five.

Here is just a partial list of the things, short of death rates, we know are affected by air pollution. GDP, with a 10 per cent increase in pollution reducing output by almost a full percentage point, according to an OECD report last year. Cognitive performance, with a study showing that cutting Chinese pollution to the standards required in the US would improve the average student’s ranking in verbal tests by 26 per cent and in maths by 13 per cent. In Los Angeles, after $700 air purifiers were installed in schools, student performance improved almost as much as it would if class sizes were reduced by a third. Heart disease is more common in polluted air, as are many types of cancer, and acute and chronic respiratory diseases like asthma, and strokes. The incidence of Alzheimer’s can triple: in Choked, Beth Gardiner cites a study which found early markers of Alzheimer’s in 40 per cent of autopsies conducted on those in high-pollution areas and in none of those outside them. Rates of other sorts of dementia increase too, as does Parkinson’s. Air pollution has also been linked to mental illness of all kinds – with a recent paper in the British Journal of Psychiatry showing that even small increases in local pollution raise the need for treatment by a third and for hospitalisation by a fifth – and to worse memory, attention and vocabulary, as well as ADHD and autism spectrum disorders. Pollution has been shown to damage the development of neurons in the brain, and proximity to a coal plant can deform a baby’s DNA in the womb. It even accelerates the degeneration of the eyesight.

A high pollution level in the year a baby is born has been shown to result in reduced earnings and labour force participation at the age of thirty. The relationship of pollution to premature births and low birth weight is so strong that the introduction of the automatic toll system E-ZPass in American cities reduced both problems in areas close to toll plazas (by 10.8 per cent and 11.8 per cent respectively), by cutting down on the exhaust expelled when cars have to queue. Extremely premature births, another study found, were 80 per cent more likely when mothers lived in areas of heavy traffic. Women breathing exhaust fumes during pregnancy gave birth to children with higher rates of paediatric leukaemia, kidney cancer, eye tumours and malignancies in the ovaries and testes. Infant death rates increased in line with pollution levels, as did heart malformations. And those breathing dirtier air in childhood exhibited significantly higher rates of self-harm in adulthood, with an increase of just five micrograms of small particulates a day associated, in 1.4 million people in Denmark, with a 42 per cent rise in violence towards oneself. Depression in teenagers quadruples; suicide becomes more common too.

Stock market returns are lower on days with higher air pollution, a study found this year. Surgical outcomes are worse. Crime goes up with increased particulate concentrations, especially violent crime: a 10 per cent reduction in pollution, researchers at Colorado State University found, could reduce the cost of crime in the US by $1.4 billion a year. When there’s more smog in the air, chess players make more mistakes, and bigger ones. Politicians speak more simplistically, and baseball umpires make more bad calls.

In 2019, a comprehensive global review by the Forum of International Respiratory Societies found that air pollution damages every organ, indeed virtually every cell, in the body. Nanoparticles of pollution have been found inside the brainstems of even the very young. But you don’t have to wait until birth to see the effects of breathing particulate matter. The impact begins in the womb, damaging the development of lungs and shortening future lives. In 2019, a small-scale study at Hasselt University found particles of black carbon in every single placenta examined, including those from mothers who lived in areas where the air was thought to be clean, with thousands of particles found in every cubic millimetre. For those who worry about microplastics in the flesh of fish, this is a yet more invasive category of intrusion. Of course, there are also microplastics in the air. They’ve been found in placentas too.

That​ everything is worse in the presence of pollution means that everything should be better in its absence. And, as best we can tell, it is. According to the National Resources Defence Council, the US Clean Air Act of 1970 is still saving 370,000 American lives every year – more than would have been saved last year had the pandemic never arrived. According to the NRDC, a single piece of legislation delivers annual economic benefits of more than $3 trillion, 32 times the cost of enacting it – benefits distributed disproportionately to the poor and marginalised. The American experience provides the basis for self-justifying indifference to pollution: according to what’s often called the ‘environmental Kuznets curve’, development makes countries dirtier before they get cleaner. This is wishful thinking, implying that pollution is an inevitable consequence of development, which can’t conceivably be achieved cleanly; and that it is in a way consensual, as if taking a job expresses a willingness to choke all the way to work. It also suggests that the effect is temporary, since societies at a certain level of wealth will refuse to put up with heavy pollution. But if more than 90 per cent of the planet’s population have lived for years in places with dangerously polluted air, 90 per cent also live where renewable energy is cheaper than dirty. This one fact renders the ‘economic bargain’ of air pollution, if it could ever be said to be credible, no better than an alibi.

In London, the gains over a single lifetime have been striking. ‘On Friday, 5 December 1952 my dad left work in South London, stepped out into the darkness and realised this was not going to be an ordinary journey home,’ Gary Fuller writes in The Invisible Killer: The Rising Global Threat of Air Pollution – and How We Can Fight Back (2018). ‘The fog was exceptionally thick. It was as if the world around him had vanished.’ He had to feel his way along the kerb all the way home.’ Throughout the city, visibility was reduced to just a yard, Tim Smedley writes in Clearing the Air: The Beginning and the End of Air Pollution. ‘People couldn’t even see their own feet. Blinded commuters stepped off bridges into the icy Thames and from railway platforms into the path of oncoming trains.’ The smoke stuck to windscreens ‘like paint, forcing drivers to abandon their vehicles’. In 1952, the fog was estimated to have killed four thousand people in London, though later estimates tripled the figure; the rate of death was higher than in the cholera epidemic of 1866. The hospitals were overwhelmed. Four years later the Clean Air Act was introduced, and in relatively short order the pea-soupers that had given the city a permanent-seeming identity – reflected in the works of Dickens, Monet and Conan Doyle – came to an end.

In China, particulate pollution has been cut by a third since 2013, when the state declared ‘war’ on it. In the 1990s, when Mexico City was more polluted than Delhi, 80 per cent of 10 and 11-year-olds asked the colour of the sky responded ‘grey’, Smedley writes; only 10 per cent said ‘blue’. Today the city only just ranks in the list of the world’s thousand most polluted cities, with air as clean as the Northern French town of Roubaix, terminus of the famous cycle race.

That those gains are so large doesn’t mean there aren’t much bigger ones to reap. In China, more than a million people still die each year from air pollution. In Africa, another million. In London, Gardiner estimates, 9500, about 20 per cent of the city’s total deaths, despite the apparent success of the Ultra Low Emission Zone. The Twitter account @CleanAirLondon has begun to tally deaths attributable to pollution by area in real time. About two-thirds of the population of the UK, Smedley calculates, are living with pollution above the legal limit set by the EU, and millions of British children are going to school in dangerously dirty air.

The World Bank estimates that as much as 6 per cent of global GDP is lost to pollution and puts the annual loss at $8.1 trillion. Last year, Drew Shindell of Duke University, an expert on pollution impact, appeared before the US House Committee on Oversight and Reform. By further cleaning up America’s air over the next fifty years, Shindell’s research shows, the country could prevent 4.5 million premature deaths, 1.4 million hospitalisations, 1.7 million cases of dementia and 300 million lost work days. The result, he calculated, would be $700 billion a year in net benefits, ‘far more than the cost of the energy transition’. In other words, a total decarbonisation of the US economy would pay for itself through public health gains alone. The American Environmental Protection Agency has an official measure for the value of a single human life: $7 million in 2006 dollars. If you take that number seriously, the annual value of saving the 350,000 lives a year lost to pollution would be $2.45 trillion.

Globally, air pollution cuts life expectancy by almost two years. The average inhabitant of Delhi would live 9.7 years longer were it not for air pollution. The figure is 8.5 years across the Indo-Gangetic plains, where 500 million people live. Cutting air pollution to the WHO standard would add 5.9 years of life expectancy to 1.38 billion Indians, 5.4 years to 164.7 million Bangladeshis and 3.9 years to 220 million Pakistanis. Annually, 349,000 stillbirths and miscarriages in South Asia can be attributed to air pollution, and 116,000 infants die from its effects in their first month.

These numbers demand that we reorder our picture of the world we live in, recalculating the brutality of the present. It becomes plain that clean air and clean water and human health should be restored to the centre of the environmental crusade – rather than at the margins, where they’ve been relegated as the movement has coalesced around the necessary project of addressing climate change through decarbonisation. (As a side benefit, clean air and clean water tend to be much more popular with voters than climate-focused environmental policies.) The long timescale of global warming has often made it hard to mobilise a majority against damage that may occur decades, or even generations, in the future. That timescale no longer looks quite so distended, after the last few years of serial disaster – fire, storm and flood – but air pollution provides an even more urgent motive for change: millions are dying, right now, because of it, and because particulate pollution dissipates much more quickly than carbon dioxide in the atmosphere, abating that pollution would save lives swiftly. Carbon hangs in the air for centuries if we don’t remove it; local pollution abates almost as soon as the match is extinguished.

There’s a further incentive for individual governments to prioritise the addressing of pollution. The benefits of decarbonisation – chiefly that it limits temperature rise – are distributed globally, which in practice means that local actors wait and see how quickly others are moving before moving themselves. Air pollution changes the calculus: for one thing, it’s actually under the control of local and national governments. It’s also a significant burden on public health, which if alleviated offers immediate benefits every government should want to seize.

A final implication of numbers as large as ten million deaths a year is that, certainly in terms of human mortality and probably in terms of human suffering, over the next few decades the toll of air pollution from the burning of fossil fuels will be greater than all the other impacts of climate change combined, at least as we currently quantify them. Global warming will of course deliver punishing and transformative impacts well below the threshold of mortality: flooding, drought, crop failure; poverty and forced migration and possibly state collapse; hurricanes and wildfire of unprecedented intensity. But as brutal as these may be, they don’t add up to anywhere near ten million deaths a year – or even one million – unless you add to most models the effects of improbable feedback loops (large-scale release of methane from melting permafrost in the northern latitudes, for instance) or widespread civilisational collapse.

Warming may well destabilise societies: it’s certainly not out of the question. But the damage done by air pollution isn’t hypothetical, and it’s happening at a much bigger scale. According to the WHO, extreme heat killed at least 166,000 people around the world between 1998 and 2017 – 8700 a year. Air pollution killed about a thousand times more. Other estimates are higher, but even the highest – the Lancet’s half a million heat-related deaths per year – is just a twentieth of the toll of air pollution. Earlier this year, Madagascar was said to be on the brink of the world’s first ‘climate famine’, with 30,000 on the verge of starvation. In the same country, Unicef estimates, more than 40,000 already die each year from the effects of air pollution. The Climate Impact Lab recently published a comprehensive accounting of the ‘global mortality consequences for climate change’. The lab, a consortium of environmental scientists and economists from a wide range of US institutions, is known for being at the alarm-raising vanguard of the serious research on the effects of warming. Their highest estimate for the end of this century – assuming an implausibly high emissions scenario called RCP8.5 – was for an annual death toll from climate change of 73 deaths per 100,000 people. Today, air pollution is killing up to 126 per 100,000. In a more plausible scenario, the report projects fewer than 20 deaths per 100,000.

Perhaps,​ like me, you have spent the last five years in a state of panic about climate change. Perhaps it has inflamed your politics, and your sense of self. It should. The world is already warmer than it has ever been in the history of human civilisation. We have already exceeded the narrow temperature window which gave rise to everything we know as agriculture and society and politics and culture. The last time there was as much carbon in the atmosphere as there is today, temperatures weren’t 1.2°C warmer than the pre-industrial base level, as they are now, but about 3°C, with forests growing in the Antarctic and sea levels twenty metres higher.

The climate is changing ten times faster than ever before in a planetary history that includes mass extinctions which wiped out more than 90 per cent of life on Earth. Half of that damage has been done in the last 25 years, since the publication of Al Gore’s first book on global warming and the formation of the UN’s Intergovernmental Panel on Climate Change – in other words, with the full knowledge of the scientific community and the effective consent of global political leaders. A quarter of the change has taken place since Barack Obama was elected president, having hubristically proclaimed that ‘this was the moment when the rise of the oceans began to slow and our planet began to heal.’ Just a few years later, he bragged to an audience in Texas that ‘suddenly, America is the biggest oil producer. That was me, people.’

In 2018 an IPCC report declared that giving the planet a good chance of staying below 2°C of warming and avoiding the catastrophic effects that would bring – island nations have called it genocide; African climate ambassadors ‘certain death’ for the continent – would require a 45 per cent reduction in emissions this decade. The report suggested that such a rapid timeline would require a global World War Two-scale mobilisation beginning the following year, 2019. Instead, emissions went up, and will be up again, it appears, in 2021, after a brief dip during the pandemic.

An IPCC report released in August also noted that air pollution has limited the level of warming, to the extent that if it were removed global temperatures would be half a degree higher than they are now. The reason: aerosols reflect sunlight back into space and therefore hold temperature rise below the level our carbon concentrations alone would dictate. Some estimates of the cooling effect run even higher: the climate scientist James Hansen believes the rate of global warming could double as aerosols decline. Cutting air pollution probably won’t produce a sudden temperature spike, because the transition would be gradual, but we would probably already be close to the 2°C threshold if we weren’t also producing enough particulate matter to kill ten million people a year.

If we fail to keep the rise below 2°C, we may see what used to be once in a century floods happening every single year; major cities in South Asia and the Middle East experiencing ‘lethal’ heat for two hundred or more days a year; the total loss of the planet’s coral reefs, which provide food, income and coastal protection to a half a billion people; and possibly irreversible acceleration of sea-level rise as a result of the melting of the Arctic ice sheets. And the climate may be more sensitive to our carbon perturbations than median estimates predict: a doubling of carbon concentrations from the pre-industrial average produces anything from two degrees of warming to six, depending on the model. At three degrees, a quarter of potential global GDP could be wiped out; in many equatorial regions there would be no hope of economic growth at all. At four degrees, crop yields could drop dramatically, and parts of the world might be hit by up to six climate-driven natural disasters at once.

All these impacts, even if unleashed, probably won’t surpass present-day air pollution in terms of human mortality for a very long time. Reducing fossil fuel pollution won’t solve the problem. Last year, wildfires accounted for more than half of the air pollution in the western United States – meaning that more particulate matter from burning forests infiltrated the lungs of Americans living in those states than from all other human and industrial activity combined. By the middle of the century, the extent of those fires is expected to double, at the very least, with each tree burned releasing carbon just as coal does, along with particulate matter. The worst air quality in the world is now routinely registered in California, and although these record-setting events typically last only a few days, it is already the case that the smoke from last year’s fires can be held responsible for five thousand additional pre-term births in the state. Globally, the world’s wildfire smoke delivers only a fraction of air pollution, but the fraction is growing. The 2021 fires are still smouldering, and wildfire emissions from this year have reached 4.7 billion tons of carbon, not far off the 5.1 billion produced last year by the US, which is the world’s second biggest emitter.

Fire is eternal in the American west, of course, but when climate sceptics point to evidence of ancient megafires, they neglect to mention that at the time there weren’t forty million people living in California. In the entire 20th century, there were only five fires that burned more than 100,000 acres. In 2020, there were eleven such fires – one blaze, the August Complex fire in Mendocino, which burned more than a million acres, seemed to demand a new term, ‘gigafire’, to describe it. Each of these fires has produced an unprecedented amount of smoke, so much of it that the fires create their own weather systems – pyrocumulus clouds, fire tornadoes and lightning storms, the lightning sometimes travelling miles from the central point of ignition, and sparking more fire where it lands, producing yet more smoke.

In some ways fear of smoke is more logical than fear of fire. In many parts of California, you can be confident your house won’t burn down. The chances are that you can evade the flames of even rampant wildfire. But smoke can’t be quarantined. This summer in the resort community of Lake Tahoe – where the Air Quality Index, which describes 51 on its scale as ‘hazardous’, hit 700 – those trapped inside during oppressive weeks of smoke finally fled their vacation homes. Poisoned air reached as far as the East Coast of the US, where more deaths are caused every year by western wildfires than in the west itself, and across the Atlantic to Europe, where around the Mediterranean unprecedented fires were already burning, forcing evacuations from resort hotels.

The story is global, the world wrapped in smoke. In British Columbia, more carbon is now unleashed each year from forest fires than from all other sources. In Australia, where bushfires are an enduring feature of both landscape and legend, 46 million acres burned in the 2019-20 season – ten times the record-setting California season that would follow, and enough to kill, it was estimated, more than a billion animals. The smoke in Sydney Harbour was so thick ferries couldn’t navigate it, and the particulates so dense that fire alarms were triggered in office buildings, the sensors concluding that there had to be flames nearby. In Siberia, where ‘zombie fires’ now burn regularly through the Arctic winter, carbon released from forests in flames regularly sends heavy smoke across the North Pole to the other side of the planet.

And then there’s South America, where 30 per cent of the Pantanal, the world’s largest tropical wetland, was lost to fire in a single year – 2020. In the Amazon, so much land is burned to clear trees for farming that the fires release three times as much carbon as all other forms of emission in Brazil – enough to make the rainforest itself, if it were a country, the world’s fifth largest emitter, and to turn the celebrated ‘carbon sink’, which might aid in our fight against warming, into a net source of global carbon. In theory, the burning could be halted, and it may at least be slowed if Lula succeeds Bolsonaro and returns to Brazil’s presidency next year. But the longer-term decline of the rainforest may lie outside the reach of national policy, as current global emissions trajectories suggest an irreversible tipping point for the region by the 2040s: less forest and more grass, less new growth and more new dying, more heat and therefore more fire. The Amazon has long been called ‘the lungs of the planet’. It may soon become a bellows. Everything we burn, we breathe.

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