At 1.24 am on 26 April 1986 Chernobyl’s Unit 4 reactor exploded after staff disabled safety systems and performed an ill-advised experiment to check – ironically enough – the reactor’s safety.

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.

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.

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 wonder what sentences judges might hand down at future international criminal tribunals on those who will be partially but directly responsible for millions of deaths from starvation, famine, and disease in the decades ahead.

If substantial methyl hydrate melt begins to occur in the Arctic Ocean basin, then the (carbon) accelerator will be jammed, and there will be nothing we can do to cut the speed of climate change.