Most scientists, on achieving high office, keep their public remarks to the bland and reassuring. Last week Nina Fedoroff, the president of the American Association for the Advancement of Science (AAAS), broke ranks in a spectacular manner.

She confessed that she was now "scared to death" by the anti-science movement that was spreading, uncontrolled, across the US and the rest of the western world.

"We are sliding back into a dark era," she said. "And there seems little we can do about it. I am profoundly depressed at just how difficult it has become merely to get a realistic conversation started on issues such as climate change or genetically modified organisms."

The remarks of Fedoroff, one of the world's most distinguished agricultural scientists, are all the more remarkable given their setting.

She made them at the AAAS annual meeting, an event at which scientists normally revel in their latest accomplishments: new insights into marine biology or first results from a recently launched satellite, for example.

But this year there has been a palpable chill to proceedings. Yes, good work was reported to the 8,000 who attended the various symposia and lectures at the meeting in Vancouver.

However, these pronouncements were set against a background of an entire intellectual discipline that realises that it, and its practitioners, are now under sustained attack.

As Fedoroff pointed out, university and government researchers are hounded for arguing that rising carbon dioxide levels in the atmosphere are changing the climate. Their emails are hacked while Facebook campaigns call for their dismissal from their posts, calls that are often backed by rightwing politicians. At the last Republican party debate in Florida, Rick Santorum insisted he should be the presidential nominee simply because he had cottoned on earlier than his rivals Newt Gingrich or Mitt Romney to the "hoax" of global warming.

"Those of us who grew up in the sixties, when we put men on the Moon, now have to watch as every Republican candidate for this year's presidential election denies the science behind climate change and evolution. That is a staggering state of affairs and it is very worrying," said Professor Naomi Oreskes, of the University of California, San Diego.

Oreskes is co-author, with Erik Conway, of Merchants of Doubt, an investigation into the links between corporate business interests and campaigns in the US aimed at blocking the introduction of environmental and medical measures such as bans on smoking and the use of DDT, laws to limit acid rain, legislation to end the depletion of ozone in the atmosphere and attempts to curb carbon dioxide emissions.

In each case, legislation was delayed by years, sometimes decades, thanks to the activities of a variety of foundations – such as the Heartland Institute – which are backed by energy companies such as Exxon and billionaires like Charles Koch.

These institutions, acting as covers for major energy corporations, are responsible for the onslaught that has deeply lowered the reputation of science in many people's minds in America. This has come in the form of personal attacks on the reputations of scientists and television adverts that undermine environment laws. The Environmental Protection Agency, which is responsible for blocking mining and drilling proposals that might harm threatened species or habitats, has become a favourite target.

"Our present crisis over the rise of anti-science has been coming for a long time and we should have seen it coming," adds Oreskes.

This point was backed by Francesca Grifo of the Union of Concerned Scientists (UCS), although she added that one specific event had brought matters to a head this year: the decision by the United States supreme court to overrule the law that allowed the federal government to place limits on independent spending for political purposes by business corporations.

"That has opened the gates for corporations – often those associated with coal and oil industries – to flood the market with adverts that support rightwing politicians and which attack government bodies that impose environmental regulations that these companies don't like," she said. "The science that supports these regulations is attacked as well. That has made a terrible difference over the past year and it is now bringing matters to a head."

Her remarks are backed by a UCS report, Heads They Win, Tails We Lose: How Corporations Corrupt Science at the Public's Expense, which was published at the Vancouver meeting on Friday. It chronicles the methods used by corporate businesses to attack their targets: harassing individual scientists, ghost-writing scientific articles to raise doubts about government research, and undermining the use of science to form government policy.

"People may believe that political interference in science went extinct when George W. Bush left office, but the reality is that the pressure to politicise science is still with us," added Grifo.

Most scientists acknowledge that President Barack Obama is sympathetic to science. "The trouble is that he still hasn't been able to do anything to help. He is continually blocked by Congress, and that only adds to our worries and sense of desperation," said Fedoroff. "If the current president is for us, but still cannot do anything to help us, then what will happen if a Republican gets into the White House this year?"

In general, the worst excesses of the anti-science lobbies are confined to the US. However, there are signs that their influence is spreading, and that raises worrying issues, said Bob Ward of the Grantham Research Institute on Climate Change, in London.

"In coming years, we will have to ask ourselves if public policies should be based on the advice of experts who have carried out robust and rigorous analysis of the evidence, or if they should be guided by lobbyists who appear driven by narrow ideological dogma.

"The answer may seem obvious, but we should be aware of the efforts being made in the UK to promote ideology over rational evidence-based decision-making, particularly when it comes to climate issues," said Ward.

Just how this rise of anti-science antagonism pans out in the end remains unclear.

"It has taken the scientific community a long time to realise what it is up against," says Oreskes. "In the past, it thought the problem was just a matter of education. All its practitioners had to do was make an effort to reach out and talk to teachers, the public and business leaders. Then these people would see the issues and understand the need for action.

"But now they are beginning to realise what they are really up against: massive organised attempts to undermine scientific data by people for whom that data represents a threat to their status quo. Given the power of these people, scientists will have their work cut out dealing with them."