There's an incredibly powerful movement opposed to action on climate change. Without doubt it had more influence on the outcome of the climate negotiations in Copenhagen than many of the world's countries combined. Obama knew if he signed up to something that would truly deliver significant cuts in global warming pollution, he'd suffer a serious blow from this movement's army of activists and its allies in the Senate. This movement's ability to make Democrats pay a serious political price – just see what they helped to do in Massachusetts where the Democrat candidate lost a recent election – shows what raw activism can look like. The name of this world-changing movement?It's the Tea Party movement, coupled with its sophisticated echo chamber of right-wing shock jocks, culture-war keyboard commandos, and allies at Fox News, all pushing the scepticism line on climate change.

Over the last few years as climate campaigners such as myself have tried to mount a good rational argument, theirs has mounted a powerful disinformation campaign. In the last few weeks we have witnessed that effective campaign gain momentum and turn into a sort of global asymmetrical warfare, with criticism of the UN's Intergovernmental Panel on Climate Change (IPCC) for its claims about the speed with which Himalayan glaciers are melting, personal attacks against its chairman Rajendra Pachauri and a persistent hounding of climate scientists and those reviewing the scientists.

Gold-standard scientific reporting from the IPCC , and indeed the value of scientific inquiry itself, is now under sustained assault from a motley assortment of cranks, ideologues and special interest voices intent on stopping the transition to a clean energy economy.

It was just these sorts of tactics that, with the Swift boat campaign questioning his military service, helped to bring down Senator John Kerry's presidential candidacy in 2004. The problem was that Kerry thought being right would be enough. His response was to be photographed going wind-surfing. In contrast, when Obama ran in 2008 and he faced a similar smear campaign attack on the basis of inflammatory comments made by his former pastor, the Reverend Wright, he knew being right wouldn't be enough. What followed was Obama's race speech in Philadelphia setting the record straight, and the rest is history.

There's still time for the IPCC to be Obama in 2008 rather than Kerry in 2004, but that's going to require a much stronger response than it's issued so far. At the moment there's a real danger that when the next major IPCC climate assessment report is released, the likes of the BBC will feel the need to spend 30% of their coverage remembering an inconsequential error about Himalayan glaciers in the last report, because the battle here is over trust and perception. On both of these fronts there can be no doubt that the scientists are losing ground. We all need the IPCC to focus urgently on rebuilding trust, and for the scientific community at large to robustly defend science itself.

Influential sceptical commentators can afford to just throw mud and see what sticks, because they have what former PM Stanley Baldwin famously attacked back in 1931 as "power without responsibility." It's the same dynamic that allowed Sarah Palin to make up "death panel" myths to distort the US healthcare debate and get away with it— those in opposition just don't face the same scrutiny as those holding the incumbent establishment position. That's why inside newsrooms the balance of legitimacy has been allowed to tilt so considerably that the climate science controversy that was largely resolved is now live once again, despite the rock solid nature of the core facts.

Prolific climate deniers such as Ian Plimer, James Delingpole and Christopher Booker who deliberately spread untruths on climate change can be wrong 99% of the time and right for less than 1% of the time and still win the argument because the playing field simply isn't level. Equally, the IPCC can be right 99% of the time and wrong less than 1% of the time, and they still lose.

The climate movement would be wrong to underestimate the damage that's been done over these last few weeks. One extremely influential British journalist told me that editors are coming under significant pressure to adopt a more contrarian stance on the climate science because they are receiving scores of emails and telephone calls daily from the public demanding a more sceptical line. They are receiving very few messages supporting the consensus scientific view.

On the web the situation is even starker. The top ten conservative blogs in Britain are all sceptical of climate science and the founder of Conservativehome.com, Tim Montgomerie, himself a climate sceptic, now compares it to Europe as a major dividing line that even splits the shadow cabinet.

If you still doubt the power of this sceptic surge, ask yourself how much of the Tory party's rump of climate scepticism can be put down to Conservative MPs and activists having read Plimer in the Spectator, or Booker or Delingpole in the Telegraph, or Iain Dale online.

The scientific community, with honourable exceptions, continues to handle the issue badly because they haven't apologised for their mistakes and come out all guns blazing on the robustness of the climate science. But utimately, as John Kerry learned, and as Obama mastered completely during his campaign, an altogether different kind of response is required anyway — one that speaks less in the language of "parts per million of atmospheric carbon dioxide" and more to people's values and everyday concerns.

I've often thought it strange and problematic that climate change became a culture war issue. Rightly or wrongly, if you "believe" the science of climate change, it's assumed that you probably read The Guardian or Independent, that you support gay marriage and opposed the war in Iraq. But of course the polarisation of society on this issue has been completely manufactured by those who seek to deliberately polarise the carbon debate by painting climate change as the latest liberal obsession.

That's why climate change has come to be associated with austerity and regulation when it could just as easily be connected with economic opportunity and national security. After all, dealing with climate change will reduce our dependence on foreign oil and gas from unstable regimes, and involve establishing a multi-trillion dollar global clean energy market, effectively a global arms race for green technologies.

Right now global warming is linked to rising energy bills and potential black outs. In fact insulation of people's homes would mean reduced energy bills, a smaller number of fuel poor, and increased energy security. This issue can and should be owned by left and right alike.

We climate activists need to ask ourselves how this whole incongruous state of affairs came about. The most zealous deniers, a subculture of outlandish paranoid conspiracy theorists, claim to speak for independent thinking when in truth they're the shock troops for a choking and insidious form of censorship, blotting out the truth with the ideology and interests of the world's most powerful Big Carbon corporates.

Climate change is real and human-caused, the case for tackling it is just common sense.

• Joss Garman is a climate campaigner at Greenpeace UK