Standing in front of the partial ruins of Rome’s Colosseum, Boris Johnson explained that a motive to tackle the climate crisis could be found in the fall of the Roman empire. Then, as now, he argued, the collapse of civilization hinged on the weakness of its borders.

“When the Roman empire fell, it was largely as a result of uncontrolled immigration – the empire could no longer control its borders, people came in from the east and all over the place,” the British prime minister said in an interview on the eve of crucial UN climate talks in Scotland. Civilization can go into reverse as well as forwards, as Johnson told it, with Rome’s fate offering grave warning as to what could happen if global heating is not restrained.

This wrapping of ecological disaster with fears of rampant immigration is a narrative that has flourished in far-right fringe movements in Europe and the US and is now spilling into the discourse of mainstream politics. Whatever his intent, Johnson was following a current of rightwing thought that has shifted from outright dismissal of climate change to using its impacts to fortify ideological, and often racist, battle lines. Representatives of this line of thought around the world are, in many cases, echoing eco-fascist ideas that themselves are rooted in an earlier age of blood-and-soil nationalism.

In the US, a lawsuit by the Republican attorney general of Arizona has demanded the building of a border wall to prevent migrants coming from Mexico as these people “directly result in the release of pollutants, carbon dioxide, and other greenhouse gases into the atmosphere”. In Spain, Santiago Abascal, leader of the populist Vox party, has called for a “patriotic” restoration of a “green Spain, clean and prosperous”.

In the UK, the far-right British National party has claimed to be the “only true green party” in the country due to its focus on migration. And in Germany, the rightwing populist party Alternative for Germany has tweaked some of its earlier mockery of climate science with a platform that warns “harsh climatic conditions” in Africa and the Middle East will see a “gigantic mass migration towards European countries”, requiring toughened borders.

Meanwhile, France’s National Front, once a bastion of derisive climate denial, has founded a green wing called New Ecology, with Marine Le Pen, president of the party, vowing to create the “world’s leading ecological civilization” with a focus on locally grown foods.

“Environmentalism [is] the natural child of patriotism, because it’s the natural child of rootedness,” Le Pen said in 2019, adding that “if you’re a nomad, you’re not an environmentalist. Those who are nomadic … do not care about the environment; they have no homeland.” Le Pen’s ally Herve Juvin, a National Rally MEP, is seen as an influential figure on the European right in promoting what he calls “nationalistic green localism”.

Simply ignoring or disparaging the science isn’t the effective political weapon it once was. “We are seeing very, very little climate denialism in conversations on the right now,” said Catherine Fieschi, a political analyst and founder of Counterpoint, who tracks trends in populist discourse. But in place of denial is a growing strain of environmental populism that has attempted to dovetail public alarm over the climate crisis with disdain for ruling elites, longing for a more traditional embrace of nature and kin and calls to banish immigrants behind strong borders.

Millions of people are already being displaced from their homes, predominately in sub-Saharan Africa, the Middle East and South Asia, due to disasters worsened by climate change such as flooding, storms and wildfires. In August, the United Nations said Madagascar was on the brink of the world’s first “climate change famine”.

The number of people uprooted around the world will balloon further, to as many as 1.2 billion by 2050 by some estimates, and while most will move within their own countries, many millions are expected to seek refuge across borders. This mass upending of lives is set to cause internal and external conflicts that the Pentagon, among others, has warned will escalate into violence.

The response to this trend on the right has led to what academics Joe Turner and Dan Bailey call “ecobordering”, where restrictions on immigration are seen as vital to protect the nativist stewardship of nature and where the ills of environmental destruction are laid upon those from developing countries, ignoring the far larger consumptive habits of wealthy nations. In an analysis of 22 far-right parties in Europe, the academics found this thinking is rife among rightwing parties and “portrays effects as causes and further normalizes racist border practices and colonial amnesia within Europe”.

Turner, an expert in politics and migration at the University of York, said the link between climate and migration is “an easy logic” for politicians such as Johnson as it plays into longstanding tropes on the right that overpopulation in poorer countries is a leading cause of environmental harm. More broadly, it is an attempt by the right to seize the initiative on environmental issues that have for so long been the preserve of center-left parties and conservationists.

“The far right in Europe has an anti-immigration platform, that’s their bread and butter, so you can see it as an electoral tactic to start talking about green politics,” Turner said, adding that migrants are being blamed in two ways – first, for moving to countries with higher emissions and then adding to those emissions, as rightwing figures in Arizona have claimed; and secondly for supposedly bringing destructive, polluting habits with them from their countries of origin.

A mixture of this Malthusian and ethno-nationalist thinking is being distilled into political campaigning, as in a political pamphlet described in Turner and Bailey’s research paper from SVP, the largest party in Switzerland’s federal assembly, which shows a city crowded by people and cars belching out pollution, with a tagline that translates to “stop massive immigration”. A separate campaign ad by SVP claims that 1 million migrants will result in thousands of miles of new roads and that “anyone who wants to protect the environment in Switzerland must fight against mass immigration”.

The far right depict migrants as being “essentially poor custodians of their own lands and then treating European nature badly as well”, Turner said. “So you get these headlines around asylum seekers eating swans, all these ridiculous scaremongering tactics. But they play into this idea that by stopping immigrants coming here, you are actually supporting a green project.”

Experts are clear that the main instigators of the climate crisis are wealthy people in wealthy countries. The richest 1% of the world’s population were responsible for the emission of more than twice as much carbon dioxide as the poorer half of the world from 1990 to 2015, research has found, with people in the US causing the highest level of per capita emissions in the world. Adding new arrivals to high-emitting countries doesn’t radically ramp up these emissions at the same rate: a study by Utah State University found that immigrants are typically “using less energy, driving less, and generating less waste” than native-born Americans.

‘Protect our people’

Still, the idea of personal sacrifice is hard for many to swallow. While there is strengthening acceptance of climate science among the public, and a restlessness that governments have done so little to constrain global heating, support for climate polices plummets when it comes to measures that involve the taxing of gasoline or other impositions. According to a research paper co-authored by Fieschi, this has led to a situation where “detractors are taking up the language of freedom fighters”.

“We are seeing the growth of accusations of climate hysteria as a way for elites to exploit ordinary people,” Fieschi said. “The solutions that are talked about involve spending more money on deserving Americans and deserving Germans and so on, and less on refugees. It’s ‘yes, we will need to protect people, but let’s protect our people.'”

This backlash is visible in protest movements such as the gilets jaunes (yellow vests) in France, which became the longest-running protest movement in the country since the second world war by railing against, among other things, a carbon tax placed on fuel. Online, favored targets such as Greta Thunberg or Alexandria Ocasio-Cortez have been shown in memes as Nazis or devils intent on impoverishing western civilization through their supposedly radical ideas to combat climate change. Fieschi said the right’s interaction with climate is far more than just about borders – it is animating fears that personal freedoms are under attack from a cosseted, liberal elite.

“You see these quite obviously populist arguments in the US and Europe that a corrupt elite, the media and government have no idea what ordinary people’s lives are like as they impose these stringent climate policies,” said Fieschi, whose research has analyzed the climate conversation on the right taking place on Twitter, Facebook, Instagram and other social media platforms.

This sort of online chatter has escalated since the Covid-19 pandemic started, Fieschi said, and is being fed along a line of influence that begins with small, conspiratorial rightwing groups spreading messages that are then picked up by what she calls “middle of the tail” figures with thousands of followers, and then in turn disseminated by large influencers and into mainstream center-right politics.

“There are these conspiratorial accusations that Covid is a dry run for restrictions that governments want to impose with the climate emergency, that we need to fight for our freedoms on wearing masks and on all these climate rules,” Fieschi said. “There is a yearning for a pre-Covid life and a feeling climate policies will just cause more suffering.

“What’s worrying,” Fieschi continued, “is that more reasonable parts of the right, mainstream conservatives and Republicans, are being drawn to this. They will say they don’t deny climate change but then tap into these ideas.” She said center-right French politicians have started disparaging climate activists as “miserabilists”, while Armin Laschet, the leader of the Christian Democratic Union who sought to succeed Angela Merkel, has said Germany should focus on its own industry and people in the face of cascading global crises.

Green-cloaked nativism

The interplay between environmentalism and racism has some of its deepest roots in the US, where some of the conservation movement’s totemic figures of the past embraced views widely regarded as abhorrent today. Wilderness was something viewed in the 19th century as bound in rugged, and exclusively white, masculinity, and manifest destiny demanded the expansion of a secure frontier.

John Muir, known as the father of national parks in the US, described native Americans as “dirty” and said they “seemed to have no right place in the landscape”. Madison Grant, a leading figure in the protection of the American bison and the establishment of Glacier national park, was an avowed eugenicist who argued for “inferior” races to be placed into ghettoes and successfully lobbied for Ota Benga, a Congolese man, to be put on display alongside apes at the Bronx Zoo. This focus on racial hierarchies would come to be adopted into the ideology of the Nazis – themselves avowed conservationists.

There has been something of a reckoning of this troubling past in recent years – a bronze statue of Theodore Roosevelt on horseback flanked by a native American man and an African man is to be removed from the front of the American Museum of Natural History in New York and at least one conservation group named after the slaveholder and anti-abolitionist John James Audubon is changing its name. But elsewhere, themes of harmful overpopulation have been picked up by a resurgent right from a liberal environmental movement that now largely demurs from the topic.

Republicans, aware that many of their own younger voters are turned off by the relentless climate denial as they see their futures wreathed in wildfire smoke and flood water, have sensed an opportunity. “The right is reclaiming that older Malthusian population rhetoric and is using that as a cudgel in green terms rather than unpopular racist terms,” said Blair Taylor, program director at the Institute for Social Ecology, an educational and research body.

“It’s weird that this has become a popular theme in the US west because the west is sparsely populated and that hasn’t slowed environmental destruction,” he added. “But this is about speaking to nativist fears, it isn’t about doing anything to solve the problem.”

The spearhead for modern nativism in the US is, of course, Donald Trump who has, along with an often dismissive stance towards climate science itself, sought to portray migrants from Mexico and Central America as criminals and “animals” while vowing to restore clean air and water to deserving American citizens. If there is to be another iteration of a Trump presidency, or a successful campaign by one of his acolytes, the scientific denial may be dialed down somewhat while retaining the reflex nativism.

The Republican lawsuit in Arizona may be a prelude to an ecological reframing of Trump’s fetish for border walls should the former president run again for office in 2024, with migrants again the target. “We will see weird theories that will spread blame in all the wrong directions,” Taylor said. “More walls, more borders, more exclusion – that’s most likely the way we are heading.”

A recasting of environmentalism in this way has already branched out in different forms throughout the US right, spanning gun-toting preppers who view nature as a bastion to be defended from interlopers – “a ‘back to the land’ ideology where you are an earner and provider, not a not soft-handed soy boy,” as Taylor describes it – to the vaguely mystic “wellness” practitioners who have risen to prominence by spreading false claims over the effectiveness of Covid-19 vaccines.

The latter group, Taylor said, includes those who have a fascination with organic farming, Viking culture, extreme conspiracy theories such as the QAnon fantasy and a rejection of science and reason in favour of discovering an “authentic self”. These disparate facets are all embodied, he said, in Jake Angeli, the so-called QAnon shaman who was among the rioters who stormed the US Capitol on 6 January. Angeli, who became famous for wearing horns and a bearskin headdress during the violent insurrection, was sentenced to 41 months in prison over his role in the riot. He gained media attention for refusing to eat the food served in jail because it was not organic.

Angeli, who previously attended a climate march to promote his conspiracy-laden YouTube channel and said he is in favor of “cleansed ecosystems”, has been described as an eco-fascist, a term that has also been applied to Patrick Crusius, the Dallas man accused of killing 23 people in a mass shooting at a Walmart in El Paso, Texas, in 2019.

In a document published online shortly before the shooting, Crusius wrote: “The environment is getting worse by the year … So the next logical step is to decrease the number of people in America using resources. If we can get rid of enough people, then our way of life can become more sustainable.” The shooting came just a few months after the terrorist massacre of 49 people in two mosques in Christchurch in New Zealand, with the perpetrator describing himself as an eco-fascist unhappy about the birthrate of immigrants.

Such extreme, violent acts erupting from rightwing eco-populist beliefs are still rare but the “‘alt-right’ has been adept at taking concerns and making them mainstream”, said Taylor. “It has fostered the idea that nature is a place of savage survival that brings us back to original society, that nature itself is fascist because there is no equality in nature. That’s what they believe.”

Advocates for those fleeing climate-induced disasters hope there will be a shift in the other direction, with some advocating for a new international refugee framework. The UN convention on refugees does not recognize climate change, and its effects, as a reason for countries to provide shelter to refugees. An escalation in forced displacement from drought, floods and other calamities will put further onus on the need for reform. But opening up the convention for a revamp could see it wound back as much as it could be expanded, given the growing ascendancy of populism and authoritarianism in many countries.

“The big players aren’t invested in changing any of the definitions around refugees – in fact the US and UK are making it even more difficult to claim asylum,” said Turner. “I think what you’re going to see is internally displaced people increasing and the burden, as it already is, falling on neighbors in the global south.”

Ultimately, the extent of the suffering caused by global heating, and the increasingly severe responses required to deal with that, will help determine the reactionary response. While greater numbers of people will call for climate action, any restrictions imposed by governments will provide a sense of vindication to rightwingers warning of overreaching elites.

“My sense is that we won’t do enough to avoid others bearing the brunt of this,” Fieschi said. “Solidarity has its limits, after all. Sure, you want good things for the children of the world. But ultimately you will put your children first.”

• Research for this article was made possible with the support of the Heinrich Boell Foundation, Washington DC’s Transatlantic Media Fellowship