Ah, St. Paul’s Cathedral! Icon of old London, shrine to the survival of the human spirit, blah blah. What better place to hear Jeffrey Sachs, celebrity economist, brain of the Make Poverty History campaign, and all-round Bringer of Solutions to Difficult Problems (oh yes, and Chairman of Columbia University’s Earth Institute), explain to us the route to a sustainable future? Except, of course, it’s actually a crap place. Because the same incredible size that gives it its majesty and overwhelming sense of solidity and timelessness also makes it a bloody echo chamber, and Jeffrey Sachs has a surprisingly booming voice.

Still, once I’d tuned my ears to pick out the words from the echoes, it made for an interesting evening. In addition to the surprising baritone, Sachs is taller than I expected, and generally less mild-looking. And his words, too, were surprisingly muscular.

Much of his 30-odd minute talk was taken up with recounting his polished summary of modern economic growth, with emphasis on the staggering increase in economic activity since the Industrial Revolution. In The End of Poverty, he talks about a 49-fold increase in total economic throughput since 1800. Tonight, he mentions 100-fold. I suspect that’s a slightly different measure, rather than new evidence having increased the figure. But who knows?

He quickly moves on to the central concern of, well, me, and I’m sure much of the audience. Is “sustainable development” really at all possible? Meeting the rich world’s current needs sustainably is looking nigh-impossible at the moment. Once Sach’s plans to plug the poorest countries into the engine of economic development takes off, surely there’s no hope?

Sachs tackles the issue with his tried and tested approach: just crunch the numbers. If the poor catch up to a large extent with us, in terms of economic throughput, and we stay roughly the same, that will mean a four-fold increase in total economic activity. Couple that with the predicted 50% increase in world population, and you’re looking at a six-fold increase in economic activity by mid-century - from a base that is already too high.

Well, that’s fairly depressing. But Sachs has no truck with the doom-and-gloom tone that tends to dominate debate about climate change. “It is possible,” he insists. “We’ve got to this point purely by absent-mindedness.” If we actually apply ourselves to the problem, he argues, there’s every chance of a solution. It’s clear he sees technology, rather than some of the lifestyle changes proposed by the traditional green movement, as the answer - he namechecks carbon sequestration and nuclear as two of twenty possible technological solutions currently being worked on.

What’s lacking, Sachs argues, is the political will. And it’s here that the muscular part comes in. Sachs rips into the War on Terror, calling it a distraction from the real issues at hand. “The War on Terror is about 27th on my list of international priorities,” he asserts, and argues that our response to 9/11 missed the opportunity to spur progress towards the Millennium Development Goals. He more than once calls the Iraq war “stupid,” and takes a potshot at George W. Bush, explaining,

right now we’re driving towards a cliff… but it’s not too late to grab the wheel and turn the car around. Right now, President Bush’s hand is on the steering wheel, so, yes, I’m worried. But we can turn the wheel around ourselves.

Sachs doesn’t get the opportunity to go into detail about the technologies and practical solutions he’s mentioned, partly because of some slightly off-topic questions from his debate partner, Nicholas Sagovsky (the version of this post on my personal blog has more on Sach’s general political views expressed this evening). He does answer a technical question about carbon sequestration, the details of which I won’t go into here because (a) it’s not really our remit, and (b) I didn’t understand a word of it. But overall, this is more of a general overview of Sach’s thinking on the issue, rather than a detailed explanation. What’s clear, and heartening, is that he really does think we can score the double-whammy - to bring the full benefits of modern economic growth to everyone, and make them compatible with humanity’s continued existence on the planet.