How Protests and Crackdowns Can Exacerbate Climate Change

Rather than relying on tear gas, water cannons, and tanks, governments should implement greener counterprotest measures.

By , a New York City-based freelance writer with an interest in environment, culture, and technology.
Police officers in riot gear are seen standing in tear gas smoke during a protest in Hong Kong on July 28, 2019.
Police officers in riot gear are seen standing in tear gas smoke during a protest in Hong Kong on July 28, 2019.
Police officers in riot gear are seen standing in tear gas smoke during a protest in Hong Kong on July 28, 2019. Vernon Yuen/NurPhoto

Since the death of 22-year-old Mahsa Amini in September at the hands of Iran’s abusive so-called morality police, protests have spread across the country. Iranian security forces have repeatedly fired at demonstrators, wounding and killing civilians who are taking part in an unprecedented show of dissent. As demonstrations intensified, fires blazed at Tehran’s Evin Prison, inside police vehicles in Noshahr and Mashhad, and throughout the country from burning hijabs, smoke billowing into the sky for days.

Demonstrations like those in Iran—and in Hong Kong, Ukraine, Russia, China, the United States, and elsewhere—are vital exercises of free speech, often essential to policy or regime change. But when clashes between civilians and police turn violent, there is an overlooked cost on both sides: the mutual destruction of shared environmental space. Tear gas, water cannons, pepper spray projectile launches, laser dazzlers, traffic barricades, fires, helicopters, and military tanks—hallmarks of modern protest and counterprotest around the world—cause injuries, endanger human life, and can violate human rights. They may also pose risks to the climate.

In 2020, a combustible mix of growing economic hardship, racial injustice, police abuse, and pandemic-related unrest led to mass protests in cities across the globe. This year, as the rising cost of fuel, inflation, and political instability roil nations from Iran to Somalia, significant anti-government protests continue to erupt. Other demonstrations have centered on climate change policies themselves: At COP27, the U.N. climate conference held this year in Sharm el-Sheikh, protesters were restricted from voicing their anger at Egypt’s deeply troubling human rights and environmental record.

Since the death of 22-year-old Mahsa Amini in September at the hands of Iran’s abusive so-called morality police, protests have spread across the country. Iranian security forces have repeatedly fired at demonstrators, wounding and killing civilians who are taking part in an unprecedented show of dissent. As demonstrations intensified, fires blazed at Tehran’s Evin Prison, inside police vehicles in Noshahr and Mashhad, and throughout the country from burning hijabs, smoke billowing into the sky for days.

Demonstrations like those in Iran—and in Hong Kong, Ukraine, Russia, China, the United States, and elsewhere—are vital exercises of free speech, often essential to policy or regime change. But when clashes between civilians and police turn violent, there is an overlooked cost on both sides: the mutual destruction of shared environmental space. Tear gas, water cannons, pepper spray projectile launches, laser dazzlers, traffic barricades, fires, helicopters, and military tanks—hallmarks of modern protest and counterprotest around the world—cause injuries, endanger human life, and can violate human rights. They may also pose risks to the climate.

In 2020, a combustible mix of growing economic hardship, racial injustice, police abuse, and pandemic-related unrest led to mass protests in cities across the globe. This year, as the rising cost of fuel, inflation, and political instability roil nations from Iran to Somalia, significant anti-government protests continue to erupt. Other demonstrations have centered on climate change policies themselves: At COP27, the U.N. climate conference held this year in Sharm el-Sheikh, protesters were restricted from voicing their anger at Egypt’s deeply troubling human rights and environmental record.

As governments turn increasingly autocratic, resources dwindle, and unrest proliferates, some experts forecast that protests will only increase. Although crowd control is sometimes a legitimate objective, the state—with its greater resources and potentially greater capacity to cause environmental destruction—has a responsibility to mitigate protests’ environmental impact. Green measures may also help ensure that protest intervention strategy is more humane and less expensive. And there are ways in which even protesters themselves could adopt more sustainable methods of demonstration.


There is little available data on the environmental consequences of counterprotest (or protest, for that matter). While the U.S. military and various nonprofits monitor the effects of tear gas on humans, for example, no organization tracks the compound’s effects on plant or animal life.

In Santiago, Chile, tear gas was repeatedly fired alongside the medians that separate city streets during protests in 2017, littering patches of green grass with chemical residue, and there were frequent reports of dead birds turning up on the Chinese University of Hong Kong’s campus during protests in the territory in 2019. (Tear gas had indeed been used.) Storage of outdated tear gas and old munitions dumps can also contaminate groundwater, and the long half-life of these chemicals makes them difficult to eradicate.

“We need more environmental transparency about the use of tear gas,” said Sahan Savas Karatasli, a researcher at the University of North Carolina at Greensboro. “These weapons live in a gray zone: The Geneva Conventions ban their use in warfare, but they are still used for domestic riot control.” The Geneva Conventions’ ban on chemical weaponry expressly prohibits the use of any asphyxiating or poisonous gases, as well as of bacteriological methods of warfare, including herbicides that might “change the composition or structure of the Earth’s biota.”

But those bans, as Karatasli points out, only apply to wartime. Karatasli’s research focuses on international political economy and social movements, and he notes that any impact evidence is anecdotal. “During the 2013 protests in Gezi Park [in Istanbul], Turkey, we saw street cats, birds, and dogs dying, presumably from tear gas; the police denied it.” Lack of government accountability or rigorous impact studies means that the picture remains murky.

Even when police do not use tear gas, they may rely on other intervention methods that can negatively impact the environment. When demonstrations form, law enforcement authorities often barricade major arteries and roadways to control crowds, forcing vehicles into bottleneck traffic jams that increase emissions. They may launch helicopters in hover patterns or stage armored military tanks or vehicles, which each consume more than half a gallon of fuel an hour when idle.

The state—with its greater resources and potentially greater capacity for environmental destruction—has a responsibility to mitigate protests’ environmental impact.

Modern water cannons, also used to disperse crowds, have flow rates of up to 20 liters (about 5 gallons) per second, expending significant volumes of water and washing the colored dyes and UV chemical markers they frequently deploy over 200 feet away. (Colored dye enables police to “tag” protesters and identify them later.) Agents such as chlorobenzylidene malononitrile, or CS, do not decompose easily; one of the most common chemicals used by law enforcement, CS may be mixed into water cannons and cause secondary impacts. Exposed streets and sidewalks are then lined with toxic residue, which is stirred into the air by traffic and pedestrians or carried into sewers by rainfall.

And there are other, perhaps more insidious ways the state can exert control and simultaneously cause environmental damage. Consider fire, an inhumane and environmentally reckless countermeasure to protest—potentially lethal and indiscriminate in the people it can kill and the property it can destroy.

“In Ethiopia, especially during countrywide protests between 2015 and 2018, some activists who protested government practices sought refuge in forests,” said Felix Horne, a senior researcher at Human Rights Watch. “Security forces then proceeded to burn some of those forests in an attempt to force the protesters out.” Fire as an answer to protest can be wildly irresponsible, especially when variables such as wind are present.

While protesters themselves may be driven to light fires, they typically do so out of desperation, exhausted by the limited tools available to express opposition. Nevertheless, tire fires in particular—either those lit by accident or intentionally as demonstrations escalate—likely have an effect on carbon emissions. Rubber tires are composed of highly combustible chemicals and release toxic fumes when they ignite, including heavy metals, volatile organic compounds, carbon monoxide, and other carcinogens. Tires have a higher per pound heat output than coal, and the flames they generate are almost impossible to extinguish. As a result, these slow-burning fires can continue to blaze for months, exuding oil into groundwater and significant pollutants into the air long after protests have dwindled.

“Protest fires occur in densely populated areas, so they may impact local air quality and health or damage infrastructure,” said Niels Andela, a research scientist at NASA. Andela consults with NASA’s Fire Information for Resource Management System (FIRMS), which provides near-real-time satellite surveillance of burning fires. At present, the technology is not sufficiently sensitive to detect urban-area protest fires. But Andela believes FIRMS’ satellite data may someday be used in conjunction with case studies to quantify the effects of fire started by protesters, police, or soldiers.

The potential environmental cost of counterprotest measures extends to the production of weaponry, not simply its use in police response. Manufacturing of smoke and irritant munitions, flash bangs, sting-ball grenades, and the like makes up a multibillion-dollar business—a global supply chain with far-flung systems that produce significant emissions. Factory leaks and explosions of chemical weaponry, though rare, sometimes occur. The U.S.-based Combined Systems, one of the largest producers of so-called security products for the global defense and law enforcement markets, has conducted no studies on the environmental impacts of its products or their manufacture.

Meanwhile, its weapons have been used to disperse protests throughout the world, including in Bolivia, Cameroon, Egypt, Sierra Leone, Tunisia, and the West Bank. At present, no law requires companies such as Combined Systems to be proactive or transparent about monitoring the environmental impact of their products.


While authoritarian leaders won’t soon concern themselves with civil resistance as a matter of sustainability, more responsible governments could at least recognize that some of their response methods might need to change. Legislative guidance could follow. “For instance, if crowd dispersal agents are causing more harm than we first thought, we could explore alternatives licensed under regimes like the Toxic Substances Control Act to allow new agents that aren’t as harmful to the environment, no matter how they are used,” said Victor Flatt, a professor of law and co-director of the Environment, Energy, and Natural Resources Center at the University of Houston.

More humanitarian counterprotest strategies may translate to more sustainable strategies. Abandoning tear gas and water cannons as a deterrent or crowd disperser, incorporating zero-emissions military vehicles into fleets, and watering tire piles as a precautionary measure to prevent prolonged burning are some alternatives that have been broached. These alternatives and their potential humanitarian consequences require further examination as well—by scientists, human rights groups, policymakers, activists, law enforcement officials, and the military. Finally, the burden of sustainability, if any exists, may not rest entirely with the state: Protesters should also minimize, to the extent possible, their harm to the environment.

When excessive force and prohibition on freedom of assembly are chief concerns—as they should be—ecofriendly protest measures are never going to be a priority. Compared with emissions from the airline and automotive industries or coal-fired power plants, for example, protest-related pollution seems minor. And green policing alternatives, while potentially less harmful to the environment, can have unintended, even dangerous, consequences for humans.

China, for example, has developed face-mapping technology to disperse crowds, a sustainable government counter-response with significant implications for privacy, while government officials in Kazakhstan recently shut down the internet in response to protests over rising energy costs there.

Whatever the environmental impact, a citizen’s unassailable right to peaceably demonstrate—enshrined in the Universal Declaration of Human Rights—must also be protected. While the true environmental costs of protests and state crackdowns remain hard to quantify, there are compelling reasons to monitor their impact and explore green alternatives for both sides.

Adrienne Bernhard is a New York City-based freelance writer with an interest in environment, culture, and technology.

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