The effects of small-particulate pollution are going to get worse with climate change. Photo: Jed Share/Kaoru Share//Getty Images

The list of crimes Donald Trump has committed against the planet, in just two years, is already so impeachably long that his slippery-fish climate denial registers as hardly more than a footnote. “I have a natural instinct for science,” the president bragged to the Associated Press Tuesday, a week after the U.N.’s IPCC raised the alarm on global warming that is much faster, and more horrifying, than it had acknowledged before. “And I will say that you have scientists on both sides of the picture,” said Trump. On Sunday, Lesley Stahl pressed the president on his contention that there were scientists saying that extreme weather had been worse in the past: “Who says that? ‘They say’?” Trump responded, defensively, “People say. People say.”

It was an especially grotesque demonstration of bad faith, given that just weeks ago, his administration had announced that, as a matter of climate policy, it was now assuming a worst-case global warming scenario — four degrees Celsius this century, an assumption suggesting that any effort to regulate American emissions would be effectively pointless. In the blink of an eye, the Republican Party seemed to pass directly from insisting that global warming isn’t happening to taking for granted a climate hellscape so inevitable that there’s nothing we can, or should, do about it.

The climate is already warmer than it has ever been at any point in human history. Should we get all the way to four degrees of warming, it will be warmer than in many millions of years, since the Arctic was effectively tropical and oceans were hundreds of feet higher. But Trump’s know-nothing-ism here is trivial compared to the cruel indifference of his actual policies: pulling out of the climate accords, of course, so spitefully that he had the band at the press conference play “Summertime” before the announcement; rolling back limits on the emission of methane, a far stronger greenhouse gas than carbon dioxide. These are environmental policies scientists say could kill 80,000 per decade (actually more: they say their findings account for just a fraction of the impact), and which even Trump’s own EPA admits would kill at least hundreds every year.

But one under-noticed horror arrived last week, when the EPA announced it was formally disbanding its own panel devoted to studying the effects of what’s called small-particulate pollution. What is that? It’s most of what you think of as air pollution — the tiny, dirty stuff that smogs up the air. It’s produced whenever you burn fossil fuels — in power plants, in cars, in coal furnaces — but also by volcanoes, dust storms, and wildfires. You can also mitigate it, using a variety of clean-up and filtration technologies that are, in just about every part of the industrialized world, required to some degree. The disbanding of this panel is a sign that, well, compared to every other advanced nation in the world, the Trump administration just isn’t going to worry about small-particulate matter very much.

This is very bad. The term “small-particulate” suggests a trivial form of pollution, but while the particles are small, the effects are actually enormous. About 9 million people die each year, globally, from small-particulate pollution — that is one out of every six deaths everywhere on the planet. This year, scientists estimated that the death toll from particulate pollution in a world two degrees warmer would be 150 million higher than at 1.5 degrees. In the U.S., the numbers are smaller, but not that much smaller: a 2013 study found 200,000 preventable deaths each year, in the U.S., from air pollution. And “lesser” effects are pervasive, too, and horrifying: small-particulate pollution causes dramatic drops in cognition, significant increases in the prevalence of mental illness, and is “strongly correlated” with dementia.

There is, actually, a silver lining here — at least that strange, now-familiar kind of silver lining for climate change, whereby awful, harrowing news seems possibly to contain the potential to wake people up from their suicidal slumber. The case for optimism is this: that a much more galvanizing appeal to action on climate change might be made from public health arguments than has yet been managed on the basis of sea level rises, which could reach six or eight feet by the end of the century; agriculture, which could lose as much as half of its global productivity; or wildfires, which could grow sixteenfold. (Sixteenfold!)

That appeal would have many component parts — there is the public-health cost of direct heat, which could make many of the most populous cities in India literally uninhabitable by just 2050, and do the same to large portions of the Middle East and North Africa by 2100, and infectious disease, which could bring malaria and other tropical diseases well beyond their historical habitats in a “globalization” of dengue, yellow fever, and Zika, among others. (At four degrees of warming, which we are due to reach by 2100, there would be 8 million cases of dengue each year in Latin America alone.)

But the mobilization against small-particulate pollution seems especially possible, because it builds on familiar and popular earlier eras of environmental protection (which cleaned up the air so you could see Los Angeles again from Malibu); because its effects are so massive (that death toll in the millions); and because it hits us, among other ways, in our brain function, which is both a core vanity and an immediate source of anxiety for most people in the modern world. There is already, emerging on the environmental left, a strange kind of admiration for Chinese leader Xi Jinping, who has seized the role of climate leader in the age of Trump — and who has taken aggressive action in recent years mostly in the name of public health. In 2013, a third of all deaths in China were the result of air pollution; since then, there has been an unprecedented cleanup of Chinese air, and yet more than a million people are dying each year there from pollution.

How big are the developmental and cognitive effects? The term researchers use is “huge” — the equivalent of having lost a year of education. Reducing Chinese pollution to the EPA standard, they found, would improve the country’s test scores by 13 percent and its verbal scores by 8 percent —potential boosts in productivity that should alarm anyone concerned about the country’s rapid economic and geopolitical ascent. (Simple temperature rise has a robust and negative impact on test-taking, too: scores go down when it’s hotter out.) Air pollution has been linked to worse memory, attention and vocabulary, ADHD, and autism spectrum disorders. A higher pollution level in the year a baby is born has been shown to reduce earnings and labor force participation at age 30, and the relationship of pollution to premature births and low birth-weight of babies is so strong that the simple introduction of E-ZPass in American cities reduced them by 10.8 percent and 11.8 percent, respectively, just by cutting down on the exhaust expelled when cars slowed down to pay tolls. Pollution has been shown to damage the development of neurons in the brain, and proximity to a coal plant can even deform your DNA.

We are still learning, in 2018, just how much social damage was done by the many varieties of lead pollution we casually countenanced all through the postwar years — IQ declines, ADHD, criminal behavior. The literature on small-particulates is much younger, but the impacts appear to be significantly worse, and every new finding seems grimmer still. It is also a reminder, if we needed one, that climate change is not just a matter of sea levels and coastlines or even wildfires in the American West and hurricanes in the Caribbean — it is an everywhere problem, enveloping everyone on the Earth in a toxic swaddle of pollution produced by burning carbon. And we are not just condemning future generations to suffer, but — in the case of small-particulates — inflicting dementia on ourselves and hindering the brain development of our children.

But there is one upside, believe it or not, to small-particulate pollution. Those particulates are one form of what is called aerosol pollution — an umbrella term for more or less everything that is now suspended in the atmosphere as a result of human activity. Globally, that pollution may be killing millions each year, and significantly diminishing the mental capacity of those who don’t die. But, while it is up there in the sky, it is also reflecting a considerable amount of sunlight back into space, which means that the Earth is somewhat cooler with that pollution — and those millions of deaths — than it would be without it. How much cooler? Estimates range from between a half-degree and a full degree Celsius. Which means that if we solve our small-particulate problem, we might also bring the planet from 1.1 degrees of warming all the way to 2 degrees — the level that the U.N. declared, just last week, an avoid-at-all-costs climate catastrophe.