The battle against global warming is being put at risk by far-left extremists in the green movement who are resisting a moderate consensus on issues such as fracking, the government's independent adviser on climate change has warned.

Lord Deben, who is chairman of the Committee on Climate Change, said those who condemn fracking as extremely damaging are taking a "nonsensical position" and called on environmentalists who take a more "sensible" view to disassociate themselves from these groups.

In an interview with the Guardian, the Conservative ex-cabinet minister, formerly known as John Gummer, argued that the best way of protecting the planet is broad agreement about practical solutions, including exploitation of Britain's shale gas reserves.

He said the fight against climate change will not be won if moderates allow their position to be associated with campaigners who have "extremist" views close to Trotskyism that are not really connected to the environment.

The chairman's remarks are likely to prove controversial with groups that strongly oppose fracking, such as Greenpeace, Friends of the Earth, and the Green Party, whose MP Caroline Lucas was arrested during an anti-shale protest in Balcombe in August. They have raised worries about the carbon emissions and potential for water contamination, air pollution, flaring and visual impact on the landscape.

However, David Cameron and many other Conservatives have hailed the technology as a way of possibly bringing down bills and boosting growth, while insisting it will be properly regulated. The prime minister declared last week that he was "going all out for shale".

Deben would not single out any particular green groups in the UK, but criticised what he called the "Christine Milne school of thought" in the environmental movement – a reference to the leader of the Australian green party, who is a senator for Tasmania.

"All of us who are environmentalists have to recognise there is a great deal of noise around the edges of people sticking up for particular answers to things, which are nonsense," he said in an interview with the Guardian.

"The people, for example, who suggest if you frack at all this is devastatingly damaging. They're wrong ... That is a nonsensical position. I do think that all of us who are sensible on this matter do have to distinguish ourselves from those who take that kind of almost theological view about all these things and those of us saying we've got to find a practical means of delivering what really matters, which is a world that stops destroying itself, whether it's on climate change or this appalling thing we're doing to the oceans.

"We won't win those battles if we allow ourselves to be associated with people who have extremist views which are not connected really with the environment. It's what I call the Christine Milne school of thought, which is very close to sort of Trotskyite politics, which is not about green. It's political. That's why I keep talking about the need to keep the consensus, because we only win if we have that broad range of consensus, which goes across all political parties."

The senior Tory said the political debate on green issues "lacks sane, loud voices" in the area of the environment. He called for the media, including the Guardian, to keep the consensus and "not play into the hands of people who want to make party political capital" out of the climate change debate.

Green Party MP Caroline Lucas speaks to protesters at Cuadrilla site in Balcombe in Sussex a day before her arrest in August. Photograph: Kristian Buus/Corbis

Asked which green groups he considered extremist, he said: "I don't want to pinpoint any particular one but very often it is particular individuals in campaign groups. They have got to be very careful of putting other things ahead of the great battle. The great battle is for the environment... Nobody could be more enthusiastic about renewables than I, but I don't much like those people who insist on one form of renewables over another, or seem to think we can jump to a renewable world in five minutes. [There] is going to have an interim technology like nuclear. There is going to be an interim period in which we are going to continue to use gas. It's better to use gas than to use coal. And in that interim period, it would be valuable if we could frack some gas in the sense that at least it would come from our own resources and it reduce our dependency on other nations and you're not carrying it long distance."

Deben also stuck up for the coalition following accusations that it has retreated from its aims of being the "greenest government ever" by moving to reduce the burden of environmental taxes on energy bills and cut subsidies for renewables.

Following the row over David Cameron's alleged call for an end to "green crap", Deben said it was "perfectly reasonable" to put environmental policies under scrutiny.

"I don't think it helps for people immediately to think questioning things that have the label green is somehow anti-environment," he said.

However, Caroline Lucas, Britain's only Green party MP, rejected the idea that strongly opposing fracking in Britain is nonsensical or in any way extremist.

"Of course we have to find practical ways of stopping climate change. That's what the whole opposition to fracking is about – not 'Trotskyite' dogma," she said.

"The fact is that up to 80% of known fossil fuel reserves must remain in the ground if we are to have any hope of avoiding dangerous levels of climate change. The widespread use of shale gas is quite simply incompatible with our international commitments to reduce carbon emissions. Standing up against a process which the evidence tells us undermines those efforts is a position based on logic - not theology."

1988: John Selwyn Gummer, then an agriculture minister, eats beefburger with his four-year-old daughter to prove beef was safe during the height of BSE scandal. Photograph: Jim James/PA

John Sauven, UK executive director of Greenpeace, said the group "supports John Gummer on many things, but he does make mistakes. His vigorous advocacy of fracking is looking like a bigger one than his famous feeding of a hamburger to his daughter during the height of the BSE crisis."Rather than cheerleading for a contentious fossil fuel that will cause local pollution and add to climate change, he'd be better off sticking up for energy efficiency and renewables. This is the only sure way to ensure jobs, green growth and stable energy bills into the future."