With Germany’s environment minister, Barbara Hendricks, also departing early and France‘s Nicolas Hulot not arriving until Monday because of legislative elections, there appeared little prospect of substantial bridge building on an issue which has caused significant tensions between Donald Trump’s administration and key US allies.

Patricia Espinosa, the UN official in charge of implementing the Paris accord, stressed that Trump‘s pullout would not make any difference in the short-term.

“We’ve all registered with regret the US decision, but at the same time the US remains a party to the agreement because it foresees a three-year period before any party can withdraw.

“So for us it is really clear that what we need to do is to go forward with implementing the accord and helping countries translate their national program into their development policies so we can get to 2018 and have a first assessment of where we stand,” she said.

Hundreds of students marched through Bologna to protest the presence of the G-7 ministers in the ancient university city, a long-standing bastion of progressive activism.

Organizer Giacomo Cossu told Agence France-Presse that Trump had given the radical environmentalist movement a shot in the arm, but said he would have been on the streets regardless.

“Trump has revealed the truth that lies behind the rhetoric of the G-7 on the environment. They want changes that suit the interests of big business. That is not our model. Ecology for us means democracy and equality. They represent the 1 percent, not the 7 billion.“

Chaperoned by hundreds of riot police, the demonstration appeared to be passing off peacefully with protestors brandishing placards declaring: “There is no Planet B” and “They think the Kyoto protocol is a Japanese erotic film.”

Trump announced at the start of this month that the US would not abide by the 2015 Paris agreement and would seek to renegotiate terms he denounced as unfairly damaging to the American economy and overly generous to India and China.

Trump said Washington would not be bound by the targets on reducing emissions of greenhouse gases set down in Paris, and will cut funding for developing countries affected by climate change.

But many analysts say Trump‘s rhetoric may make little difference.

Important players in US industry and individual cities and states are already implementing changes aimed at meeting the targets laid down in Paris, where most of the world’s countries agreed to try to cap global temperature rises at 2 degrees Celsius above pre-industrial levels.

Germany and California agreed Saturday to work together to keep the Paris accords on track and the most populous US state had its own representative at the Bologna talks.

Scientists warn that failing to contain climate change will have devastating consequences as sea level rise and extreme storms, droughts and heat waves becoming more common, endangering crops and fragile environments with knock-on effects in the form of new conflicts and mass fluxes of people escaping affected areas.

The G-7 comprises Britain, Canada, France, Germany, Italy, Japan and the United States, the world’s seven biggest economies when the club was formed.

The discussions in Bologna were also attended by Chile, the Maldives, Ethiopia and Rwanda, four developing countries with a particular interest in combatting climate change.