Gosh, I do hope Bjørn Lomborg doesn’t think I was trying to pick him up. I’ve only just learned from his Wikipedia entry that he’s ‘openly gay’ which, with hindsight, probably made my dogged insistence that we conduct our interview in his cramped hotel bedroom look like a cheap come-on. Not to mention the way I sat there throughout, mesmerised and sometimes lost for words under the gaze of the handsome, trim 43-year-old blond’s intensely sincere Danish blue eyes which never leave yours for one second.

But it’s OK, Bjørn. You were safe all along, I promise. The reason for my awe is quite simply that I believe you are one of the heroes of our age. You’ve been called the antichrist, been vilified ad hominem in numerous scientific journals, even had custard pies thrown in your face (at Borders bookshop, Oxford, by an eco-activist), but still you’ve stuck to your guns and continued bravely to reiterate what for a time seemed almost unsayable.

Lomborg’s basic argument — as laid out in his bestsellers, The Skeptical Environmentalist and Cool It! — is that the world isn’t in nearly as bad a mess as the eco-doomsayers claim it is. And before we do anything too drastic to try to make things better, we ought first to ascertain what its most pressing problems are, rather than throw good money after hopeless causes.

Lomborg’s latest venture is a body he has founded called the Copenhagen Consensus. Funded mainly by the Danish government, this research panel comprises 50 leading economists, including five Nobel Laureates, and has spent two years applying cost benefit analysis methods to a list of global challenges — disease, pollution, conflict, terrorism, climate change, water and so on.

Its conclusions are hardly likely to win Lomborg new fans in the eco movement, for global warming comes so far down the list of urgent priorities that it doesn’t make the top ten. Far better to spend our limited pool of development aid money, say the economists, on schemes like micronutrient supplements (vitamin A and zinc) for malnourished children. For an annual outlay of only $60 million this would result in yearly benefits (through improved health, fewer deaths, increased earnings) worth more than $1 billion.

Also high on the list are unglamorous things like expanded immunisation coverage for children; deworming programmes in Third World schools; and community-based nutrition promotion. Number two on the recommended list is the — highly unlikely given resistance from the US and the EU — implementation of the Doha development agenda. Ending the trade tariffs, in other words, which are immeasurably to the developing world’s disadvantage.

‘It’s true that in the battle between exciting problems and boring problems we are defenders of the boring problems,’ agrees Lomborg, when I suggest that polar bears on melting ice caps tug the heartstrings far more effectively than flyblown African urchins. ‘Our uphill task is to try to show that problems involving the greatest pictures and the cutest animals are not necessarily the most pressing issues.’

This is the sort of dull pragmatism that so often gets Lomborg into trouble. People will read him saying that the threat to polar bears has been somewhat exaggerated, given that their global population has increased fivefold since the 1960s, and they’ll think: ‘Heartless, evil Bush shill, probably in the pay of Big Oil.’ Whereas all Lomborg is actually saying in his remorselessly logical, Danish statistics professor’s way, is: ‘Let’s take emotion and hysteria and fluffy white fur out of the argument and try to seek the objective truth.’

Ah, but what do economists know anyway? Aren’t decisions regarding the environment, nutrition and so on better left to experts in those fields? ‘But if you ask a malaria expert where the money is best spent, you shouldn’t be too surprised if the answer is malaria,’ says Lomborg. ‘What economists can do which natural scientists cannot is, in effect, to put the prices on the menu. They are not saying, “You should pick this meal or that meal.” What they are saying is, “If you pick the lobster, you’ll have less to spend on everything else.”’

The principal question Lomborg encounters is, ‘Why should we have to pick and choose? Why shouldn’t we be able to do it all?’ He even heard this line from a US congressman, who said, ‘I can understand why a small country like Denmark has to focus on priorities, but America is so big.’ ‘I had to remind him that even though the US is indeed a lot bigger, it still seemed to me that in the last 50 years it hadn’t yet fixed all the problems in the world.’

What non-economists tend to have difficulty understanding, says Lomborg, is the concept of marginal benefit. ‘We tend to think in terms of absolute magnitude, so people will say, “Global warming is overall a bigger problem than micronutrition so we should deal with that first.” But what economists say is, “No. If you can spend a billion dollars and save 600,000 kids from dying and save about two billion people from being malnourished, that’s a lot better than spending the same amount to postpone global warming by about two minutes at the end of the century.”’

In the early days of his campaigning, when he first transformed himself from left-leaning Greenpeace-supporting tree-hugger to environmental ‘skeptic’, Lomborg used to get a lot more stick than he does now. His unlikely ally, he says, has been the ongoing biofuels disaster, whereby a scheme introduced to help save the environment has helped bring about riots, rising food prices and the destruction of rainforest. ‘People have suddenly started to realise: “Ew! Not every drastic measure we take in panic is smart!”’ he says. (The American-accented ‘Ew’ bit, by the way, is the only moment where he sounds remotely camp.)

Unlike proper climate change sceptics (who are the equivalent, George Monbiot has famously claimed, of Holocaust deniers), Lomborg says his views on global warming are broadly in sympathy with those of the Intergovernmental Panel on Climate Change (IPCC). Where he thinks the green movement has got things badly wrong is in attempting to shut down any form of critical opposition.

‘You cannot have a conversation about the biggest policy argument of the day, and then say that one side isn’t allowed to debate,’ says Lomborg. He thinks the greens have also done their cause a great disservice by talking up the climate change threat. ‘You can overplay your cards and screech so loudly that you end up losing the argument.’

The battle for common sense, though, is far from over. His worry is that the next Kyoto update — the Copenhagen summit in 2009 — will prove yet another wasted opportunity where politicians set themselves ever higher pie-in-the-sky targets on carbon emissions. ‘The danger is not that we’re not going to meet these targets, because I take that as granted — of course we’re not going to meet them, just as we didn’t after Kyoto in 1997. What’s far worse, is that yet again, it will stop us focusing on all the incredible things we actually could do with that money. So we end up wasting another ten or 20 years.’