Climate change scepticism is likely to surge in 2010 and could exacerbate "hardship" for the planet's poorest people, one of the world's leading authorities on climate change has told the Guardian.

Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change (IPCC), gives a news conference at the Bella center during the U.N. Climate Change Conference (UNCCC) in Copenhagen in this December 12, 2009 file photo. (REUTERS/Casper Christoffersen/Scanpix/Files) Writing on environmentguardian.co.uk today, Rajendra Pachauri, the chair of the UN's Intergovernmental Panel on Climate Change, also dismisses suggestions that he is personally profiting from policies to tackle global warming.

Climate sceptics gained media attention in the run up to the Copenhagen climate summit after alleging that hacked emails between senior climate scientists showed that an important temperature record was flawed — a charge rejected by governments and scientific bodies. In Australia, sceptics within the party led to the ousting of the leader of the opposition over new climate laws.

Pachauri predicted this year would see further scepticism. "Powerful vested interests are perhaps likely to get overactive in the coming months, and would perhaps do everything in their power to impede progress towards a binding agreement that is hoped for by the end of 2010 in Mexico City," he said. "Those opposed to action on climate change are working overtime to see that they can stall action for as long as possible."

After a weak deal in Copenhagen, Pachauri warned that allowing scepticism to delay international action on global warming would endanger the lives of the world's poorest people. "In the end, knowledge and science will undoubtedly triumph, but delay in reducing emissions of greenhouse gases would only lead to worse impacts of climate change and growing hardship for the most vulnerable regions in the world, which are also unfortunately some of the poorest communities on Earth."

Pachauri, a vegetarian, has previously described western lifestyles as unsustainable and advocated a diet including one meat-free day a week. He singled out lobbyists in the US for attempting to delay America's climate legislation, which is crucial for a global deal but is currently stalled in the Senate. Last year the Centre for Public Integrity found that 770 companies and interest groups hired an estimated 2,340 lobbyists to influence US policies on climate change, while America's oil, gas and coal industry increased its lobbying budget by 50%.

Pachauri said action from President Obama would be needed on top of Senate legislation. "The passage of legislation in that country [the US] will have to be supplemented with several initiatives to be put in place by the executive branch of the government," Pachauri said.

Bob Ward, policy and communications director at the Grantham Research Institute on Climate Change and the Environment, said Pachauri was right on the level of sceptical activity. "We are already witnessing extraordinary efforts by powerful lobbies, in the US and Australia in particular, which are opposed to the regulation of greenhouse gas emissions. There is a strong alliance of ideologically driven right-wingers, who reject environmental legislation on principle, and lobbyists for some hydrocarbon companies, who place the short-term commercial interests of their clients ahead of the wider public interest. Both have the common goal of delaying restrictions on greenhouse gas emissions, and both use the tactics pioneered by the tobacco industry, hiding their true motivations behind inaccurate and misleading claims about uncertainties in the science."

But Tony Kreindler of the Environmental Defence Fund, which has been following US climate legislation, said the number of climate sceptic lobbyists was now being matched by companies supporting legislation to cap carbon emissions. However, he added: "Opponents of action and the old sceptics will of course ramp up their lobbying this year as well, as they do anytime the Congress is on the verge of making law. We already have a bill through the House of Representatives and a bipartisan effort underway in the Senate. The President made his commitment clear in Copenhagen to legislation because it's in our national interest. This year is not a dress rehearsal, and everyone on both sides gets that."

On the stolen emails, Pachauri said the contents did not impact on climate science, adding that "the allegations made on the basis of the stolen emails have proved incorrect."

The University of East Anglia is currently undertaking an independent review of the hacking incident, led by senior civil servant Sir Muir Russell. The review is expected to be published in the spring, but a university spokesman said today that Sir Russell will "determine his final timescale after completing his initial scoping exercise". He added that the university had also responded to a letter from the science and technology committee of MPs asking for an explanation of the incident. The IPCC is conducting its own review into the stolen emails.

Pachauri also rebutted claims in The Sunday Telegraph that, through advisory roles for Deutsche Bank, Toyota, Yale University, the Asian Development Bank and others, he was reaping personal financial gain from climate change policies that could be influenced by the reports of the IPCC he chairs. The article claimed Pachauri had been silent on the "highly lucrative commercial jobs", the rewards from which "must run into millions".

In response, he said: "The same group of climate deniers who have been active across the Atlantic have now joined hands to attack me personally. As for pecuniary benefits from advice that I may be rendering to profit-making organisations, these payments are all made directly to my institute, without a single penny being received by me."

The Nobel Peace-prize winning Pachauri called for greater activism and more campaigning to press governments into taking strong action on carbon emissions this year. "Society and grassroots action would have to come into their own, not only to ensure that human society takes responsibility for action at the most basic level, but also to create upward pressure on governments to act decisively. If such grassroots efforts do not spread and intensify, nation states may not be able to resolve the differences that exist between them."