Jair Bolsonaro’s neglect of the Amazon has made him “the most despised and detested leader” on earth, Brazil’s former environment minister has claimed, as the far-right leader again rebuked French president Emmanuel Macron for challenging his environmental record.

Rubens Ricupero warned Bolsonaro was wreaking havoc on both Brazil’s environment and its global standing, as Bolsonaro used Facebook to scold Macron’s “inappropriate and gratuitous attacks” over the Amazon fires and insult France’s first lady.

“These people are lunatics,” Ricupero said of Bolsonaro’s administration in an interview with the Guardian.

“In my opinion, he has turned himself into the most despised and detested leader in the world. I can’t see anyone else – not even Duterte in the Philippines … not Trump, not anyone – who today provokes so much anger.”

“Never, in more than 50 years of our history, has there been a disaster involving Brazil’s image and the perception of Brazil so serious and probably so irremediable as this one,” added Ricupero, who was also Brazil’s finance minister and ambassador to the United States.

“Even in the military period – when Brazil had a negative image above all because of human rights, torture and disappearances – what went on here never drew so much attention as now.”

On Friday, amid a barrage of domestic and international censure, Bolsonaro ordered Brazilian troops to the Amazon to help contain the conflagration and professed “profound love” for a region environmentalists accuse him of helping destroy.

But Bolsonaro has continued to dismiss the crisis as a campaign of “fake news” and “disinformation” designed to discredit his government.

“We are doing what we can,” the rightwing populist told reporters in the capital, Brasília, on Saturday. “The Amazon is bigger than the whole of Europe. Even if I had 10 million people I wouldn’t be able to prevent these fires.”

At the G7 summit, Macron is pushing for world powers to help put out the fires and fund reforestation and management projects in the Amazon.

Ricupero, Brazil’s minister for the environment and the Amazon in the early 1990s, admitted fighting illegal deforestation was a massive task in a sprawling region where the government’s presence was limited and environmental criminals often armed and dangerous.

“It’s a wild west like in the American films,” Ricupero said of the Amazon. “[It’s not like] Sussex or East Anglia … Even in the best circumstances – even when a government is determined to enforce the law – it is an uphill struggle.”

But Ricupero accused Bolsonaro’s government of simply “folding its arms” when it came to protecting the Amazon, giving criminals a carte blanche to destroy by undermining Brazil’s environmental agency, Ibama.

“Bolsonaro has the same mentality as the military rulers in the 1970s: that the Amazon should be colonzied and become soy plantations and cattle ranches,” Ricupero said.

“In the 1970s the government had a slogan: ‘Amazonia will be colonized by hooves of cows’. They never accepted the idea that the Amazon had to be preserved. They see no reason for the forest not to be chopped down and replaced with agriculture and mining. This is his Bolsonaro’s mindset.”

Marina Silva, Brazil’s environment minister from 2003 until 2008, said she felt “deep sadness and anger” at the devastation unfolding in the region where she was born and raised.

Silva agreed Amazon destruction was not a new phenomenon.

“We’ve had fires and deforestation under every government – but with the difference that [before] you had environment ministers … who were genuinely committed to protecting the forests, biodiversity and our water resources,” Silva said.

By contrast, Bolsonaro’s environment minister, Ricardo Salles, was “an anti-environment minister” actively working against nature. “Instead of strengthening his employees he strengthens the offenders,” Silva said.

Ricupero said: “He isn’t a minister – he’s an anti-minister. He’s the opposite of what a minister should be.”

Ricupero said he feared Bolsonaro’s antagonistic reaction to European criticism meant international cooperation to control the destruction would be hard.

Only “the fear of economic consequences” – such as a boycott of Brazilian products or the halting of a trade deal with the EU – were likely to make Bolsonaro’s Brazil change course. “If nothing concrete happens, beyond the complaints … this will continue getting worse,” he predicted.

Bolsonaro continued his attacks on Macron on Saturday, accusing the French president of treating Brazil like “a colony or a no man’s land”.

Bolsonaro’s education minister, Abraham Weintraub, branded Macron a characterless, “opportunistic knave” and “a cretin”, while Brazil’s president mocked the French first lady’s appearance on Facebook.

Ricupero said: “The impression I have right now is that Brazil is committing suicide. That the president himself is ‘suiciding’ the country. It is a strong expression – but it’s what I feel. Destroying your own patrimony is tantamount to suicide.”