This is like playing Russian roulette with a Luger rather than a revolver. One bullet, one chamber - and we're pulling the trigger.

Human releases of carbon dioxide are almost certainly happening faster than any natural carbon release since the beginning of life on Earth.

Only by advocating 'politically unrealistic' CO2 concentrations can runaway global warming be avoided. But what is politically realistic for humans is whollymunrelated to what is physically realistic for the planet.

I am also sorry that I helped to start the anti-GM movement back in the mid 1990s, and that I thereby assisted in demonizing an important technological option which can be used to benefit the environment.

We no longer need to discuss whether or not it is safe – over a decade and a half with three trillion GM meals eaten there has never been a single substantiated case of harm. You are more likely to get hit by an asteroid than to get hurt by GM food.

We humans, one species of animal amongst millions, have now become the de facto guardians of the planet's climate stability.

The worst case scenario sees the Amazon rainforest burning, huge amounts of methane being released by Siberian peat bogs and so on - by the time today's six year olds are 60, such a scenario would see global warming already out of control.