Atmospheric acid test: Can the successes of reducing acid rain apply to the current climate crisis?

Democrats and Republicans once worked together to solve an environmental crisis. That sentence, admittedly, reads a bit like the start of a fairy tale. Long gone are the days when Republicans seemed to produce quasi-environmentalist presidents like Theodore Roosevelt and Richard Nixon. At the time of this writing, every single frontrunner for the Republican Party's 2024 presidential nomination denies that humanity's burning of fossil fuels is emitting greenhouse gases like carbon dioxide, which significantly contributes to global heating.

Even as our species struggles with climate change-linked catastrophes like unprecedented heat, rising sea levels and extreme weather events such as wildfires, the climate change denier playbook is to throw any arguments they can think of at the evidence and thereby create confusion and doubt. The consequence is evident everywhere: Instead of being a rallying point that brings everyone together out of mutual self-interest (since all people are at risk from climate disaster), addressing climate change is instead politically controversial. From the special interest groups that profit from climate change to the ordinary partisans motivated by political tribalism, a coalition has emerged to make it maddeningly difficult to effectively address global warming.

Yet there is hope, at least if history serves as any guide. During the last third of the 20th century, the United States was confronted with another serious environmental problem, one that destroyed thousands of trees in American forests, slaughtered countless insects and aquatic animals and eroded buildings by peeling paint and corroding steel. It was the acid rain crisis, and even though wealthy special interests opposed action, the forces of environmentalism actually prevailed... with Republican help, no less.

OK, but what is acid rain, anyway? Although it either sounds like hellish, skin-melting precipitation or an LSD-loving hippie's dream come true, the problem of acid rain was and is "multidimensional," as Syracuse University Professor of Environmental Systems Charlie Driscoll told Salon. It develops because sulfur dioxide (SO2) and nitrogen oxides (NOx) are released into the air, such as when electricity is generated or cars are driven. When the gases produced for electricity or by cars combines with the oxygen and water already in the air, it forms what is known as acid rain — or rain with a pH between 4.2 and 4.4.

As with climate change, there can be natural causes for acid rain, such as volcanic eruptions, but the quantity and severity of acid rain began to increase significantly in the mid-20th century due to human activity.

"It's reducing the growth and survival of trees," Driscoll said, referring to acid rain both past and present. "It's decreasing biodiversity. The increases in nitrogen will enhance invasive species. A lot of this is increasing the potential for wildfire. And in coastal areas, there are problems with the loss of sea grass, loss of oxygen. The fishery habitat is being degraded because of ongoing air pollution problems from mucosal areas."

Not surprisingly, once acid rain was discovered in the 1960s by scientists like ecologist Gene Likens, the scientific community reached a consensus: Human activities were damaging the environment, harming humans and wildlife alike. Something needed to be done.

"The really successful aspect of acid rain control was the passage of amendments to the Clean Air Act, which happened in 1990 during the [President George H. W.] Bush administration by a Republican president," Rachel Rothschild, assistant professor of law at the University of Michigan Law School and author of "Poisonous Skies: Acid Rain and the Globalization of Pollution," told Salon. "It had bipartisan support in Congress and it put in place a cap-and-trade program for acid rain that led to significant reductions in the two pollutants that our most responsible for acidifying precipitation: sulfur dioxide and nitrogen oxides." Even better, "it was also considerably cheaper than even the EPA had predicted at the time, let alone industry."

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How was such a seeming miracle possible? To answer that question, Harvard University History of Science Professor Naomi Oreskes traced the history of environmentalism back to the 1970s. That was a decade in which a senator from Maine named Edmund Muskie, who was a staunch environmentalist, seemed destined to be elected president over Richard Nixon in the 1972 election.

Although Muskie's candidacy would ultimately fizzle out due to Nixon's infamous dirty tricks against him, for a time Nixon thought he would need to beat Muskie. As such, he began passing environmental legislation so he could preempt one of Muskie's signature issues. Thus Nixon created the Environmental Protection Agency and the National Oceanic and Atmospheric Administration, as well as amended various bills to strengthen regulators' ability to clean up the environment.

"We know that Richard Nixon was not a great environmentalist, even though some people have tried to claim that; in hindsight, he was not," Oreskes told Salon. "But he understood that the American people wanted environmental reform and he understood that if he didn't do things like sign these key pieces of legislation, that he would be super vulnerable."

Clearly this type of open-mindedness to environmental concerns — one motivated by a healthy fear of negative public opinion — would not fit the agenda of wealthy business interests that profit from pollution. By the 1980s, the Republican president was Ronald Reagan, "and Reagan really shifts the tenor and the tone of the discussion of environmental issues on the Republican side of the aisle," Oreskes recalled. "Reagan says that trees are polluting. He says that ketchup is a vegetable."

Even though Reagan lacked the political support to outright repeal environmental legislation, he simply refused to adequately enforce those same measures. Meanwhile the right-wing movement became suffused with anti-science advocates, particularly those who feared any environmental regulation would be inherently tyrannical. Yet the process of transforming the party into an all-out anti-science vehicle was a slow one; it would not be finalized until the presidency of George W. Bush and vice presidency of Dick Cheney.

"Reagan begins to shift away from environmental protection in the Republican Party, but it's not wholesale at that time," Oreskes pointed out. There were divisions in the Republican Party, and as such, when George H. W. Bush became president, he was open to hearing from scientists as well as business interests that wished to continue polluting. Instead of rejecting the very notion of environmental reform, Bush chose a market-based policy that would go down more smoothly with business interests and moderate conservatives. He wound up implementing these policies through amendments to the Clean Air Act in 1990.

While Oreskes and Rothschild both agreed that the Republican Party of the 2020s is much more intransigent in its hostility to environmentalism than the version of the 1990s, the two animals are not entirely different beasts. If there is a lesson to be learned from the acid rain story, it is that the coalitions which oppose environmental reforms are not monolithic. Within their ranks there are always those who stubbornly refuse to accept scientific facts that they find inconvenient, and they will need to be worked around rather than worked with — but there will also be many other opponents who can be persuaded, given the right pressures. Even though neither Nixon nor Bush were tree-huggers, they both wound up making important contributions to protecting the planet on the domestic scene because they were not just pressured, but pressured effectively.

Nor were the achievements of the anti-acid rain coalition limited to domestic politics. In a 2019 article for the scientific journal Ambio, researchers from the United States, Sweden, Finland and Norway detailed the extensive and impressive international cooperation that existed to confront acid rain. Even though the Cold War was a time when the United States-led West and the Soviet Union-led East barely communicated, "acid rain broke the ice and formed an opening for scientific and political collaboration, resulting in a treaty under the United Nations' Economic Commission for Europe (UNECE), the Convention on Long-range Transboundary Air Pollution (often mentioned as CLRTAP but in this paper we call it the Air Convention) signed in 1979. Eight protocols have been signed under the Air Convention committing parties to take far-reaching actions, not only with respect to acid rain but also with respect to several other air pollution problems." As a result, the air pollutants most responsible for producing acid rain dropped across the board since the late 20th century; "for the most important acidifying compound, sulphur dioxide, emissions in Europe have decreased by 80% or more since the peaks around 1980–1990," the authors conclude.

What are the underlying lessons from both the domestic and international fights to stop acid rain?

"I am both a lawyer and a historian, so part of my interest in working on a project like acid rain is to try to think about the lessons of our past environmental challenges for today," Rothschild explained. "For me, I think the thing that was so powerful when working on the acid rain book that I wrote was actually interviewing a lot of the scientists who had spent their whole careers trying to understand and document this phenomenon and try[ing] to advise policy makers the public about what to do to solve it."

Even though it was a "struggle" as regulated industries pushed back, the scientists did not give up. "Seeing those scientists stay the course [and] do their best to try to be spokespeople for the environment was really powerful for me," Rothschild recalled.

Of course, acid rain is not entirely eliminated, though it has been beaten back significantly. "There are recent studies that have come out that are showing still lingering effects on tree growth and survival from certain species. Not all species, but some species that are highly sensitive," Driscoll told Salon. "It could benefit from additional reductions. And I think those reductions will occur because I think coal is phasing out and has been phasing out pretty quickly. And so then the other two are nitrogen oxides, and that's mostly from mobile sources, although there are some from electric utilities. As we transition to electric vehicles, that's going to take a little bit longer, but that is also decreasing."

Yet there is a new villain: Ammonia, which is produced overwhelmingly from agriculture, is not regulated and is therefore increasing. Ammonia is a colorless gas that can rise into the air and fall back to earth, changing the composition of soil and water, killing fish and plants.

"It's a growing problem," Driscoll explained. "Until we deal with these residual effects ... I mean, we have come a long way. It's a amazing success story. I cannot overstate that." At the same time, "we have the ammonia problem. And until we control that, that that will be contributing to the problem as well. So in a nutshell, that's the story."