An “induced implosion” of the fossil fuel industry must take place for there to be any chance of avoiding dangerous global warming, according to one of the world’s most influential climate scientists.

Professor Hans Joachim Schellnhuber, an adviser to the German government and Pope Francis, said on Friday: “In the end it is a moral decision. Do you want to be part of the generation that screwed up the planet for the next 1,000 years? I don’t think we should make that decision.”

Schellnhuber was speaking at a major science conference in Paris, taking place before a crunch UN summit in December, also in the city, at which nations must seal a deal on global warming. World leaders were sent a stark message in the communique issued by the conference, which warned that the opportunity to avoid disaster is rapidly diminishing.

Laurence Tubiana, France’s climate change ambassador, said the aim of the UN summit is to send a signal that the transition from coal, oil and gas to a low-carbon economy is inevitable. If the aim is achieved, Tubiana told the Guardian, “you will see a massive acceleration [to a greener economy], particularly on the investment side in the next five years”.

The conference was addressed by Nobel prize-winning economist Joseph Stiglitz, who said the fossil fuel industry faced big challenges: “A mixture of many different changes going on – consumption patterns, civil society, political action – will be disruptive to the carbon economy.”

Stiglitz, Schellnhuber and Tubiana all expressed support for the global divestment campaign, which lobbies investors to sell their stocks in the biggest fossil fuel companies. “I fully support the divestment movement,” said Schellnhuber. “Do you want to be part of an economy that is destroying the world, or part of an economy that protects creation?”

Tubiana said the recent call by major European oil and gas companies for a price to be put on carbon pollution was partly the result of the “very important” divestment movement. She said: “Oil companies are like canaries in the mine. When there is no danger they are silent, but when they feel danger and opportunity they make a move.”

The Guardian is divesting from fossil fuels and is campaigning for the world’s biggest health charities, the Bill & Melinda Gates Foundation and the Wellcome Trust, to do the same.

The Paris conference was attended by more than 2,000 scientists from 100 countries. Schellnhuber told the delegates: “In order to stay below 2C (3.6F) [the internationally agreed limit for global warming], or even 3C, we need to have something really disruptive, which I would call an induced implosion of the carbon economy over the next 20-30 years. Otherwise we have no chance of avoiding dangerous, perhaps disastrous, climate change.”

“The promise of the fossil fuel age has never been fulfilled,” he said. “We still have 2bn people living on $2 (£1.30) a day – that is crazy.” He called for two strong messages to come from December’s UN summit: that “the age of carbon is over” and that “it is not the poor of the world who will pay for the transition”.

To achieve these outcomes, Schellnhuber said: “We need a global social movement and it is already happening.” He said the best analogy for the transition from dirty to clean energy was the abolition of slavery, which was fundamentally driven by ethical concerns.

The scientists’ communique said that tackling climate change is economically affordable, but that nations “waiting on the sidelines” will cause the costs to rise. It said global warming is already inflicting damage across the globe and that failing to act will lock in the dangers.

Stiglitz backed the affordability of tackling climate change: “Creating a green economy is not only consistent with economic growth, it can promote economic growth,” especially when there is a lack of demand in the global economy.

He said the best option for an enforceable climate deal was for willing countries to introduce carbon taxes and then penalise nations refusing to do the same with border taxes on their exported goods.

A voluntary agreement could not solve the climate crisis, he said: “The atmosphere is a public good – all want to get the benefits, but no one wants to pay the cost.” He also dismissed carbon markets as being too prone to political lobbying: “It is basically giving away money.”

Stiglitz said it was unsurprising that a carbon price has proven hard to implement on a worldwide scale. “If you own fossil fuel assets, and the impact of any global agreement on climate change is going to push their value down, you are going to resist, using whatever tactics. But the interests of global society have to overcome these narrow special interests.”