An expert panel led by the former chief scientist Ian Chubb has warned ministers that controversial scientist Peter Ridd is misrepresenting robust science about the plight of the Great Barrier Reef, and compared his claims to the strategy used by the tobacco industry to raise doubt about the impact of smoking.

The warning, in a letter to the federal environment minister, Sussan Ley, and the Queensland premier, Annastacia Palaszczuk, follows Ridd launching a lecture tour in which he has repeated his claim that farmland pollution does not significantly damage the natural wonder.

Ridd’s tour has been supported by rightwing commentators and sugarcane industry managers campaigning against proposed state regulations limiting sediment and chemical runoff on the reef coast.

Signed by Chubb, the head of the independent expert panel advising on plans to protect the reef, the letter says the group did not have a view on the regulations but it had chosen “not to sit by and watch” while the science was disputed and sometimes misrepresented.

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“This advice to you was triggered by the roadshow of Dr Ridd and the associated industry response to new regulations aimed at improving water quality in the [reef] area,” Chubb says in the letter.

“It is our advice to you that the science we have seen and discussed during our 15 meetings has been conducted according to the most rigorous and widely accepted processes employed by professional scientists.”

In an appendix to the letter, headed “for information”, the panel likens the campaign against reef-related science to strategies used by the tobacco industry and others to delay policy responses by claiming doubt existed where there was none.

It quotes Alexander Nix, the former chief executive of election-disrupting firm Cambridge Analytica, who said: “It sounds a dreadful thing to say, but these are things that don’t necessarily need to be true as long as they’re believed.”

“We have seen the sowing of doubt play out over the years: tobacco use, lead in petrol, anti-vaccination, climate change are examples. And now possibly the GBR,” the panel says. “In all cases, scientific evidence is, or was, disputed, only sometimes for obvious reasons – usually money.

“The tactic of sowing doubt works, because there can be reluctance to change policy or regulation in the face of doubt. But absolute certainty is rare. It does not mean that what we know is wrong.”

The panel says science works by steadily accumulating evidence, drawing deductions and modifying them if conclusions are disproven by further work. Consensus occurs when accumulated evidence from independent scientists converges on a conclusion.

“It is up to people or scientists with another view to provide evidence established by rigorous application of the same scientific process and have it subjected to the same level of scrutiny by experts,” it says.

The panel says if the sowing of doubt does not work “the next step in the now time-honoured tactic is to invoke the notion of a conspiracy of the world’s scientists all working together to stop the outside getting their results published, or accepted”.

Ridd’s speaking tour has been hosted by regional branches of the sugarcane growers peak body, Canegrowers, and the Australian Environment Foundation, a charity set up by the rightwing thinktank the Institute of Public Affairs, with strong links to the agriculture and fossil fuel industries.

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The new regulations were announced by the Queensland government in February, partly because farmers were not taking part in voluntary programs that offered incentives to improve practices.

Ridd was last year found to have been unlawfully dismissed by James Cook University for criticising his colleagues’ research on the impacts of climate change. Asked to respond to the letter, he said: “Does this mean that we have no right to ask questions, to doubt, or to just ask for some decent quality assurance?”

He said organisations were in denial if they claimed there were no problems with reef science. “They should argue the science, and the issue of quality assurance, before smearing our reputation by saying we are tobacco deniers,” Ridd said.

The panel’s letter says the scientific evidence that underpins understanding of the condition of the reef is clear: the northern two-thirds were severely bleached in 2016 and 2017; there had been signs of recovery in some areas but the recruitment of coral spawn into bleached areas had fallen by up to 89%; that coral had a better chance of survival in cleaner water; that global heating was the greatest risk to the reef; that poor water quality due to nutrients, sediments and pesticides was also a major threat.

“We believe that given the direction that quality science points, suitable policy and focussed regulation are both essential if we are to give the GBR a decent chance of survival in anything like its historically recognisable form,” the letter says.