A disrupted climate and diminished natural world are widening the dividing lines of ideological debate. Left unchecked, this will undermine democracy.

That may not be the first thing on the minds of British voters as they go to the polls on Thursday. It is probably also a minority view in the rest of Europe or the US, where people are too much in the thick of a polycrisis to consider anything outside politics and economics as usual. But from a distance, in my case from the Amazon rainforest, there is a very different explanation for the tremors being witnessed in the old world and the new.

How rising emissions distort our political ecosystems is not nearly as well understood as the scientific certainty that they are heating our world. Hundreds of academic papers detail the tipping point risks of an anthropologically altered climate, but very few look at the feedbacks on governance and ideology. One thing, however, is certain: all of the world’s systems – biological, physical, economic and political – are coming under more climate stress and the longer this is left unabated, the greater is the likelihood that something will break.

Democracy is starting to look almost as fragile as the rainforest. Politicians in the traditional parties will not face the fact that they are no longer living in the stable climate in which that political system was created. The right wants to go back to a past that no longer exists. The left wants to move towards a future that it will not dare to fund.

Meanwhile, market zealots and xenophobes, fuelled by fossil fuel money, are using the unfolding chaos to frighten voters and take the opportunity to replace social safety nets and environmental protections with higher walls and rapacious extraction.

Here in Brazil we saw, with the previous, far-right president, Jair Bolsonaro, the extremes that the ancien regime is willing to go to hold on to what it has and to burn what remains of the forest. The return of the left in the guise of President Lula has brought a respite but only slowed the pace of destruction. This is a global story. The climate crisis has pushed the right towards zealotry, and made the left appear timid.

The latest tremor shook France, where the far right – once a reviled fringe – secured more votes than any other bloc in the first round of voting in a snap parliamentary election. This followed European elections in which mainstream political parties were shaken by the alarming gains of candidates with anti-immigrant, anti-science, pro-Russian agendas. Meanwhile, the threat of a second Donald Trump victory looms in the US and Britain’s Nigel Farage hopes to ride into parliament on the waves of fear, doubt and deception that have discombobulated the country since Brexit.

These ever more extreme politics are, not coincidentally, coming at a time of ever more extreme weather.

In the past month alone, more than a thousand hajj pilgrims died of heatstroke and related diseases as temperatures soared to 51.8C in Mecca, Saudi Arabia. Record heat in Delhi and other Indian cities killed at least 176 people, followed soon after by record floods. Roads also turned into rivers in northern Italy, Switzerland, central China and eastern Malaysia. The wildfire season has already started in Greece. A category 5 hurricane has formed in the Atlantic in June for the first time in history, wreaking havoc across the Caribbean. Social and political norms are taking as much of a battering as infrastructure and livelihoods.

Alleviating this situation requires state intervention and mass redirection of capital towards renewables, heat pumps, electric vehicles, sustainable agriculture and the whole net zero shebang. Just as important is patience, international cooperation and belief in a better future – all of which seem to be in decline.

In the UK, until recently, there was strong cross-party support for action. When the Climate Change Act was passed in 2008, only five of the 646 MPs voted against it. The vote in favour of net zero in 2019 was also overwhelming. But in the last two or three years, that consensus has started to unravel as the stakes started to rise, patience thinned, and the right went on the offensive.

Since 2021, Britain’s rightwing press – the Telegraph, the Daily Mail and the Sun – has mostly treated net zero as a wedge issue, with numerous politicians following suit. The Conservative politician and former Ukip deputy leader Craig Mackinlay recently told the US news site Politico he expected net zero and energy security to be the political battleground for the next 10 years: “It is an infinitely bigger issue than Brexit.”

This is gnawing into the roots of conservatism. The Tory party’s traditional instinct to conserve national and natural heritage is being eroded by a neoliberal urge to tear up regulations and exploit every resource to extinction. Rishi Sunak has backtracked on net zero and made North Sea gas and motoring central thrusts of his election campaign.

If the Tories lose this week, as the opinion polls predict, the party’s hard right will push harder still against climate action. Any success by the Reform party, which is partly funded by climate sceptics, will add to the pressure. If a Farage-isation of British conservatism seems outlandish, consider the fact that the US Republican party also used to consider itself a stout defender of the environment.

The story is similar in other countries, where democracy’s failure to deal with the causes of the climate crisis has opened the way for ultranationalists to score points by focusing on the consequences, particularly migration. The far right no longer denies climate change, it uses it as a bogeyman to frighten voters and argue for stronger barriers to keep out refugees.

The climate scientist Michael Mann has identified a “coalition of the unwilling” that knows international cooperation and regulation is the only way to deal with the climate crisis, and so sows dissent, doubt and distraction. As examples, he cites Russia’s use of bot armies, trolls and hackers to get climate activists to fight one another, to dig up private emails, which led to the “Climategate” scandal and damaged Hilary Clinton’s campaign against Trump in 2016, and to seed arguments on social media against carbon pricing in Canada or stir up yellow-vest protest in France.

Some far-right parties have received funding or support from Russian banks and businessmen, such as Marine Le Pen’s National Rally in France and Trump in the US. It is alleged that more than a dozen MEPs from across five countries also took substantial sums of money from Russia’s Voice of Europe news agency, a matter that is still under investigation.

More brazenly, Trump has asked oil executives for $1bn for his campaign and promised, in an effective offer of a quid pro quo, that, if he wins, he will loosen drilling regulations, cut support for electric vehicles and withdraw the US once again from the 2015 Paris climate agreement.

The left finds itself on the back foot, not entirely sure of how to respond to these attacks, just as with the anti-immigration line. The Labour party in the UK, like the Democrats in the US and the New Popular Front in France, has rightly focused on environmental justice and the benefits of climate action: clean-tech jobs, energy security and healthier communities. But it is trapped within the constraints of neoliberal economic orthodoxy, which means it can only move as fast or as slow as the market allows it to go.

That could delay some of the worst climate impacts, but it almost certainly will not be enough to change the perception that the situation is deteriorating. So it will start to seem that action on the consequences produces more results than action on the causes, which will play into the hands of the right, the petrostates, the oil firms, the warmongers and nationalist media.

In that sense, the traditional left is almost as poorly equipped to deal with this challenge as the mainstream right. Both emerged in the industrial era, strapped into the straitjacket of national self-interest and capitalist economics. In every country for most of the last century, left and right happily colluded on the need to materially “develop” the nation and expand gross domestic product with infrastructure projects, increased trade and greater consumption. The argument between them was only about how much of the economic pie the government should distribute between rich and poor.

The dividing line is far more complex in today’s climate-disrupted, nature-depleted world. Just as important now is the quality of the pie, where the ingredients came from, and the extent to which overconsumption is leading to obesity, cancer, climate instability and global conflict. Put more simply, politics is now a battle between those who want to fix what is broken and those who want to keep breaking. Many on the old left may not be comfortable with this 21st-century dividing line, but this is the issue that will determine the habitability of our world.

Facing up to that is an essential step in envisaging a better future. It will not be easy while so many other countries are drifting towards hostility, insularity and short-termism. But in the long run, it is the only chance democracy – and, indeed, humanity – has got. Labour’s challenge, should it win, will be enormous.