Look closely at an Extinction Rebellion rally and you may see, among the flags featuring the movement’s hourglass logo, another symbol: a green peace sign, turned upside down. Squint, and it could look like a branching tree. This is the symbol of the Stop Ecocide campaign, an initiative set up by the lawyer Polly Higgins, and led by her until her death from cancer last year. Stop Ecocide want to make the large scale destruction of the environment a crime against peace, like genocide.

Higgins spent ten years proselytising, but only in the past year has her idea caught on. Extinction Rebellion made it a demand and, in November 2019, Pope Francis said he was considering making ecocide a sin. There is no single solution to the climate and ecological crisis, but increasingly a number of people think Higgins imagined the nearest thing to it.

Higgins defined ecocide as “the extensive destruction, damage to or loss of ecosystem(s) of a given territory, whether by human agency or by other causes, to such an extent that peaceful enjoyment by the inhabitants of that territory has been severely diminished.” She intended this definition to cover environmental destruction on the scale of the 2010 BP oil spill which was considered to be the largest ever: 134 million gallons leaked in the Gulf of Mexico, killing between two and five trillion fish and nearly 200,000 turtles. It cost the fishing industry an estimated $247m.

Last summer’s fires in the Amazon could be another example. They were largely thought to have been started by ranchers and loggers. President Bolsonaro, in office since January 2019, had overseen a sharp drop in fines dished out for environmental infractions whilst also taking resources and protections from officials who were supposed to enforce them. It amounted to tacit support. If ecocide were made an international crime, then Bolsonaro could be tried in the International Criminal Court (ICC).

With cases of genocide and other war crimes, the ICC does not try the foot soldiers following orders, but the politicians and generals who issued those orders. Similarly, if ecocide passed into law, politicians and CEOs would be deemed to have ultimate responsibility and would be the ones tried.

The proposed law would also criminalise large-scale commercial activities such as tar sand oil extraction and deforestation. This would render many destructive business models unviable and should, in theory, allow more environmentally friendly ones to flourish.

Supporters argue economic disruption is a small price to pay to protect the ecosystems on which civilisation depends. Resources from the natural world are currently being consumed at 1.7 times the rate they can replenish themselves. In May, Jared Diamond, a Pulitzer Prize winner and professor of geography at UCLA, told New York Magazine that, unless we slow the rate we are exhausting fisheries, soils and freshwater, he would estimate “the chances are about 49 per cent that the world as we know it will collapse by about 2050”.

“Sooner or later,” says Jojo Mehta, who now runs the ecocide campaign, “the state to which we’re reducing the ecosystems on which we depend is going to dictate that a law like this has to come into place. What we are trying to do is get ahead of the game and make sure this law comes in sooner so we have time to adapt.”

Expanding the remit of the ICC is a surprisingly simple process. Any state can propose an amendment to its governing document, the Rome Statute. If two-thirds of the 123 ICC member states back it, then it will apply to those two-thirds. If eight-tenths back it, it will apply to everybody. Perhaps Donald Trump would withdraw from the ICC rather than allow American CEOs to be put on trial, but even if he did, they could still be tried for overseeing ecocide in ICC signatory countries. But Mehta hopes nobody would need to be tried, because companies would be granted time to transition to new business models.

Higgins and Mehta long ago gave up trying to convince wealthy post-industrial nations. Instead, Mehta now mostly lobbies countries at the front line of the climate and ecological crisis, such as Vanuatu, the South Pacific island nation threatened by sea level rises. Votes from these smaller nations are just as powerful in the ICC as those from larger countries. On 2 December of last year, at an assembly in the Hague, John Licht, Vanuatu’s ambassador to the EU, said: “We believe this radical idea merits serious discussion.” It was the first time a state representative had called for ecocide to be a crime since 1972 when it was raised by Swedish politician Olof Palme at a UN environmental conference in Stockholm.

Licht’s statement was a strong hint that Vanuatu may soon submit the amendment. Mehta hopes that, once one government submits, worldwide pressure will encourage other governments to do so.

Critics of the Stop Ecocide campaign say that the imposition of this law would collapse the economy. Polly Higgins liked to assuage this fear by comparing it to the fears of business leaders two hundred years ago, who said the economy would collapse if the slave trade was abolished. It didn’t. She wrote in her book, Eradicating Ecocide, that “within just a year of rendering slavery unlawful, traders were profitably trading in other commodities, such as tea and china”.

This analogy with abolishing the slave trade is beguiling. It suggests consumerism could simply go on as before. But, whilst the process of changing international law might be surprisingly simple, the scale of change it would bring to our everyday lives is vast. It would change what we eat, by increasing the cost of beef and other foods linked to deforestation. It would change what we wear, by putting an end to fast fashion. It would change our choice of gadgets, transport, and much else.

If the Stop Ecocide campaign succeeds it will need to argue that a more frugal existence might actually be a happier one, but also that we have no alternative.

Ben Cooke is a staff writer at the Times