Wildfires have partially reversed crucial progress on clean air
What, if anything, can we do to fix it?
Something I like to emphasize here on Slow Boring is that people are often unaware of good news about environmental policy success stories.
The “worst case scenario” RCP 8.5 climate change situation, for example, has become much less likely over time, but you continue to see it cited as the source for the most dramatic possible articles about climate impacts. Similarly, people rarely talk about how much cleaner America’s rivers and lakes have become since the Clean Water Act or about the positive steps that continue to be taken here. Last July, Matt Walsh mockingly asked us to remember the dire warnings about acid rain and the ozone hole from when we were kids, seemingly unaware that what happened here is policymakers took those warnings seriously, implemented regulatory solutions, and mitigated the problem. Here’s a great study, for example, on the long-term benefits of the Acid Rain Program which not only reduced acid rain but had seemingly gigantic co-benefits by reducing the amount of low-level soot hovering around the sky.
Similarly, the Clean Air Act appears to have done a lot to raise earnings in previously high-pollution areas and contribute to the narrowing racial gap in life expectancy, but people don’t talk much about how much cleaner the air is as a result of these rules.
Of course air quality has been in the news lately because things got worse — with big clouds of smoke and dust kicked up by Canadian wildfires drifting over New York City and then down to D.C. California and other western cities, meanwhile, have had several seasons of really bad wildfire smoke in recent years. The air quality on these bad smoke days is much worse than the conditions on an average day back in the Bad Old Days, even as today’s average day is a lot better than things used to be.
I was hoping the news on how this nets out would be relatively benign, but the best research available seems to deliver some pretty bad news: in western states, about half the gains from the Clean Air Act have been rolled back by increased wildfires since 2016, with small but meaningful impacts elsewhere.
Air pollution is really bad
There are a number of factors that determine how clean the air is, including levels of ozone and sulfur (which contributed to acid rain), but the biggest one in terms of impacts on human health turns out to be the amount of particulate matter, which is classified for regulatory purposes as either PM10 (smaller than 10 microns) or PM2.5 (smaller than 2.5 microns). One of the really interesting scientific discoveries of our time has been the revelation that inhaling lots of super-tiny PM2.5 pollutants has really serious effects on people.
There’s extensive evidence that the fine particulate matter that’s floating in the air on high pollution days impairs cognitive abilities. On high-pollution days, investors make worse trading decisions, baseball umpires blow more calls, chess players make more blunders, and British MPs speak at a lower grade level. This is also true of work that’s normally thought of as less-skilled — we see lower efficiency at pear-packing factories on high-pollution days. Prolonged exposure to pollution increases the risks of Alzheimer’s and dementia.
PM2.5 also kills lots of people.
The reason for the incredibly good retroactive cost-benefit analysis of the Acid Rain Program is largely that its increased regulation of coal power plants cut down on PM2.5 emissions, averting many premature deaths — a benefit that is only tangentially related to the initial concern. Appreciation of the deadly nature of particulate pollution is critical to becoming nuclear-pilled because you’ll see that an extremely low-CO2 source of energy is being held to an arbitrarily high safety standard that makes it uneconomical. Overreaction to Three Mile Island caused countless deaths via air pollution, and that’s true even if you think taking another path would have generated multiple Chernobyl-scale mishaps.
Still, despite this very significant implementation gap, the air has gotten a lot cleaner over time. Here’s EPA data showing a very large decline in average particulate emissions over a not-that-long timespan.
And for some other pollutants like carbon monoxide that have been monitored longer, we see even larger declines from the bad old days of persistent smog.
Of course the world abroad is different. When I went to China in 2009, they had really bad air in Beijing — stinging throat and itchy eyes like on a wildfire day in the contemporary United States. Yiwu was blanketed in a persistent haze like I remember from visiting LA as a little kid. Then we went to Dalian in the northeast and the clean air there was a huge selling point for the city endlessly touted by local officials. These days, China has cleaned up a bit and the worst air in the world is generally in India. An average day in Delhi is 100 micrograms per square meter of PM2.5 — which was worse than D.C. on June 7 though not as bad as we got on June 8.
That kind of persistent bad air seems to be a bug in the economic development process. When a country goes from “very poor” to “poor,” lots of people get dirty low-end motorbikes, drive old cars, diesel backup generators, and other high-pollution consumer goods. Eventually you come out the other side — Chinese air quality is improving now — but it can be a bit of a rocky road. That said, the key thing about bad air associated with economic development is that on net it’s clearly better not to be poor. The wildfire-induced air quality regression in the contemporary United States isn’t like that. The trees burning is not accomplishing anything useful, it’s just making the air worse.
Increased wildfires are a big problem
How much worse? Well, a big team — Marshall Burke, Marissa L. Childs, Brandon De la Cuesta, Minghao Qiu, Jessica Li, Carlos F. Gould, Sam Heft-Neal, and Michael Wara — had a big working paper out about this earlier this year. They concluded that the increase in wildfire frequency since 2016 was a major speed bump that partially reversed decades of improving air quality. I think it’s important to be clear that they are still saying American air is cleaner than it was when I was born. The news isn’t that bad. But it is bad.
Steady improvements in ambient air quality in the US over the past several decades have led to large public health benefits, and the policies that helped drive these improvements are considered landmarks in successful environmental policymaking. However, recent trends in PM2.5 concentrations, a key pollutant, have stagnated or begun to reverse throughout much of the US. We quantify the contribution of wildfire smoke to these trends and find that since 2016, wildfire smoke has significantly slowed or reversed previous improvements in average annual PM2.5 concentrations in two-thirds of US states, eroding 23% of previous gains on average in those states (equivalent to 3.6 years of air quality progress) and over 50% in multiple western states. Smoke influence on trends in extreme PM2.5 concentrations is detectable by 2010 and is concentrated in a dozen western states. Wildfire-driven increases in ambient PM2.5 concentrations are unregulated under current air pollution law, and, absent additional intervention, wildfire's contribution to regional and national air quality trends is likely to grow as the climate continues to warm.
And of course while I do think PM2.5 is the most important part of air quality, the wildfires haven’t done as much to set back progress on ozone and other relevant indicators. D.C., for example, used to have 20+ “code red” days on a typical summer (Los Angeles was worse), which stopped thanks to coal plant closures and cleaner cars. To an extent, this all leaves me ambivalent about the state of media coverage.
It’s good that people are more aware today of air quality issues and are better situated to take action in terms of HEPA filters and KN95 masks. It’s also good that we have a growing awareness of the social benefits of things like air quality performance standards for buildings. I wish more people would acknowledge that a good reason to reduce historical preservation rules is to make it easier for more people to have access to well-insulated homes with up-to-date HVAC systems.
But at the same time, I don’t want people to have the impression that they are currently living through an intolerable hellscape. What we’re living through is an era of higher variance in air quality that’s nonetheless better on average than what many of us grew up with in big metro areas.
That said, I also don’t want to be a literal “this is fine” dog while North America goes up in flames. Wildfires are very bad and we should ask what we can do to staunch the bleeding and hopefully improve things. One obvious thing that comes up here is climate change, since hotter temperatures (all else being equal) lead to drier forests and faster-spreading fires. I spent a little time trying to kick the tires on exactly how solid the specific attribution science is here, and as is often the case, the reality is more complicated than the most simplistic headlines. What the IPCC says with medium confidence is that “weather conditions that promote wildfires (fire weather) have become more probable in southern Europe, Northern Eurasia, the USA, and Australia over the past century,” but it’s not super clear to me how large the impact of that is on the actual incidence of fires compared to other factors. In terms of this specific set of fires, it seems like scientists expect climate change to lead to more rain in Quebec, which should make fires there less rather than more likely.
Rob Meyer quotes Kent Moore, an atmospheric physicist at the University of Toronto who says “this is probably an unlucky year for Canada, as far as wildfires go” rather than necessarily a durable trend. By contrast, the increase in western wildfires is what’s expected from the climate models. Introspecting on this a little, I decided that my actual opinion about climate change — that it’s bad, that we should do things to reduce CO2 emissions, and that I think the climate left’s focus on blocking fossil fuel infrastructure is bad economics and bad politics — doesn’t really hinge on this question. Let’s reduce regulatory barriers to clean energy deployment, and let’s try to price carbon emissions as part of needed long-term deficit reduction. But let’s also try to think about fires qua fires.
Only you (or better luck) can prevent forest fires
One of the things that makes climate attribution difficult is that while the weather sets the stage for fires, in practice it is often human activity that is the proximate cause of a blaze. So while climate mitigation is important due to the sheer breadth of impacts, in terms of wildfires specifically, the low-hanging fruit probably relates more to people blowing off the fire rules than anything else.
Clare Frank, a former head of fire protection in California, wrote a great op-ed about this in the NYT that I’m surprised didn’t get more attention:
If we look at California’s 10 most destructive fires, eight were caused unintentionally — more than half of them in the past 10 years. Of the 10 deadliest, six were unintentional, and they killed 169 people. A month before Caldor started, the unintentionally ignited Dixie fire raged for 104 days. By the end of October 2021, the two fires had incinerated over 1.1 million acres, an equivalent to a two-lane highway stretching over 400,000 miles — a drive around the earth’s circumference more than 16 times.
Too often, we treat fire foolishness with sympathy instead of accountability. “It was an accident.” “Mistakes happen.” “Who could have known?” My favorite is blame shifting — “It was an act of God.” I’ve heard utility companies use this as their go-to refrain when predictable regional winds down power lines into dry grass at the base of poles no one bothered to clear around.
I understand where the impulse to go soft on this kind of thing comes from. The people who recklessly ignore burn bans and safety rules are generally nice, normal-ish people just doing hobbies and not like “bad guys.” But the harms of wildfires are very large and we should try to be stricter about them. For utilities, too, being tougher will push up energy costs, but so would dramatically accelerating decarbonization. The link to fires around mismanaged power lines is much more direct.
The other elephant in the room is improving our management of the fires themselves.
Twentieth-century efforts at total suppression of forest fires have left a bad legacy in terms of the accumulated buildup of fuel for fires. You can see why people thought it was a good idea, but it fundamentally wasn’t sustainable and we’re now digging ourselves out of a hole of bad forestry practice over and above whatever’s happening with the weather. But here I want to note that a lot of the American discourse, including Frank’s, is based on the social, economic, and geographic conditions of California. Ted Nordhaus and Alex Trembath wrote a piece I find persuasive back in September 2020 calling for an expensive and labor-intensive approach to clearing out the fuel.
Right now, though, we’re talking about Canada. The province of Quebec has three times California’s land area and fewer people than LA County. Manitoba is about 20% bigger than California and has half the population of Orange County. This is just to say that whatever Canada does is inevitably going to have to be something a lot cheaper and less labor-intensive than what would be appropriate for California. My understanding is that across significant swathes of the country they basically just “let it burn,” and it’s hard to see very much improvement on that.
Which is just to say that while the situation in the American West seems both significantly impacted by climate change and also remedial through better forest management, in Canada, it’s not super-clear to me there’s all that much that can be done to prevent large fires from generating smoke. We sort of have to hope that Moore is right and this is just bad luck, and in a secular sense the relevant parts of Canada will be wetter as well as warmer and this just won’t happen repeatedly. I like to have better solutions than that to offer, but while there’s a lot that can be done to improve air quality in general, this particular issue seems a bit like a unfixable fluke.