Ten Billion, Theatre Upstairs, London

Imagine that an asteroid has been discovered and there is hard, predictive evidence that it is going to impinge on the Earth on 25 March 2072 and destroy 70 per cent of the planet’s resources.

Governments and scientists would rally together on red-alert to try to deflect the disaster and plan for the grim future it would leave in its wake. In Ten Billion, his compelling 70 -minute talk at the Theatre Upstairs, Stephen Emmott, who is the head of Microsoft’s Computational Science Laboratory, offers powerful arguments to suggest that we are on an equivalent collision course with catastrophe because of overpopulation and climate change. So why is there no commensurate urgency of action or brutal honesty of thoughts?

Governments hide behind the idea that they have to wait for the scientists to calculate the extent and the cost of the impact so that they can carry public opinion with them. In one of his deadly asides, the mild-seeming Emmott, with his gentle Northern accent, remarks that they don’t seem to wait for public opinion where going to war or messing with the NHS is concerned.

The lecture explains how human ingenuity and cleverness got us into this mess in the first place and then demolishes the Rational Optimist’s view that those very gifts can help us “technologise” our way out of it. Aided by some excellent digital graphics, he makes vivid the complex interdependencies within the atmosphere and biosphere and the knock-on effects of initiatives that would create as many problems as they solve. What would desalination plants mean to coastal and marine ecology?

Only radical behavioural change will make any difference, Emmett argues. In this collaboration with director Katie Mitchell, he looks a bit uncomfortable delivering his message as a “solo piece” from a set that he describes as “a frighteningly accurate” repro duction of his office in Cambridge.

The talk sometimes blinds you with its blizzard of statistics. If you wish to know the staggering number of litres of water it takes to make one Big Mac, Emmott is your man.

And if you are allergic to false consolation, then he is just what the doctor ordered, too, with his unsettling reports on how the military has started to attend climate conferences and how it may well all be too late.

31 July to 11 August (020 7565 5000)