The Prince of Wales has criticised "corporate lobbyists" and climate change sceptics for turning the earth into a "dying patient", in his most outspoken attack yet on the world's failure to tackle global warming, made shortly before he is to take over from the Queen at the forthcoming meeting of the Commonwealth.

His intervention was reinforced by Lord Stern of Brentford, author of the 2006 report on the economics of climate change, who called sceptics and lobbyists "forces of darkness" who would be "driven back".

Prince Charles attacked businesses who failed to care for the environment, and compared the current generation to a doctor taking care of a critically ill patient.

"If you think about the impact of climate change, [it should be how] a doctor would deal with the problem," he told an audience of government ministers, from the UK and abroad, as well as businesspeople and scientists. "A scientific hypothesis is tested to absolute destruction, but medicine can't wait. If a doctor sees a child with a fever, he can't wait for [endless] tests. He has to act on what is there."

He added: "The risk of delay is so enormous that we can't wait until we are absolutely sure the patient is dying."

His words were swiftly leapt on by climate sceptics. The Global Warming Policy Foundation, led by Lord Lawson, which opposes what it terms costly policies to reduce greenhouse gas emissions, said the heir to the throne was "out of touch with half the UK population".

Hosting a two-day conference for forest scientists at St James's Palace in London, Prince Charles – who is taking over from the Queen at this year's meeting of the Commonwealth in Sri Lanka – savagely satirised those who stand in the way of swift action on the climate.

He characterised them as "the confirmed sceptics" and "the international association of corporate lobbyists". Faced with these forces of opposition, "science finds itself up the proverbial double blind gum tree", he said.

Stern picked up on his comments, saying: "I think the forces of darkness can be driven back – the sceptics and corporate lobbyists can be driven back."

Others were supportive of the Prince's views. Mark Barry, head of sustainable business at Marks & Spencer, tweeted: "Prince Charles' attack on climate sceptics is significant. As he nears throne many expect him to back off – he isn't."

Ian Cheshire, the chief executive of the retail group Kingfisher, said some businesses were committed to strong action on climate change and greenhouse gas emissions, and could see the benefits of dealing with the issues.

Supporters of the Prince also said privately that he should be praised for taking a strong stance on such a key issue, and was using his "convening power" to draw attention to a crisis that is engulfing the planet and is not receiving sufficient attention from politicians.

But Benny Peiser, of the Global Warming Policy Foundation, said the Prince was "happy" for consumers to pay more in their energy bills for green policies, and accused him of using "apocalyptic language that a government minister would not use".

He said: "The US energy price is one third that of Europe, and European businesses are panicking [over measures intended to cut carbon] – Europe is becoming less and less competitive. Prince Charles has to address these concerns – there are real costs to be paid [for cutting emissions]."

The St James's Palace audience included Owen Paterson, the Tory secretary of state for the environment, said by some who know him to be sceptical of the scientific consensus on climate change, and who left climate change out of his speech and focused on other environmental issues such as biodiversity.

Ed Davey, the Lib Dem secretary of state for energy and climate, used his speech to the conference to draw a deep dividing line between his own party and the increasingly vocal section of the Tory right wing that is attacking policies that require tougher emissions targets and more money for the low-carbon economy. He said: "As a politician – particularly as a politician in a coalition – you quickly realise that compromise is a part of the game. But there are some issues where you have to draw the line – where you have to stand up and be counted, and you have to do the right thing. I think climate change is firmly in that category."

Prince Charles is no stranger to controversy, having spoken out on issues from organic farming and alternative medicine to architecture. But his words – warmly welcomed by the conference – were his strongest yet on climate change, an issue he has taken a deep interest in. He founded his working group on forests, whose conference he was addressing on Wednesday, in 2007, and also lends his name to a group of businesses, the Corporate Leaders' Group, which supports corporate action on cutting greenhouse emissions. He has also written to government ministers on the subject of climate change.

In his speech, Prince Charles praised countries such as Brazil, which has taken a lead on reducing deforestation, and Norway, which is offering billions of dollars to developing nations to protect their forests.

The scientists at the Prince's forum endorsed a call for much greater investment on "big science, which supports the integration and expansion of global tropical forest monitoring networks" and "enhanced research" into the resilience of forests. About a billion people all over the world depend on forests for their livelihoods, and although the rate of deforestation has slowed in countries such as Brazil, it is accelerating over swathes of south-east Asia and Africa.