How many deaths are acceptable? 1 million? 10 million? 100 million?

Our planet is reeling from massive amount of greenhouse gases being pumped in the atmosphere, at around 10 billion tons per year. The human race has already produced 370 billion tons of CO2 from the dawn of the Industrial Revolution. Scientists expect a "tipping point" at 500 billion tons of CO2, that would lead to irreversibly altering the planet's climate for hundreds, and maybe thousands of years. At the rate humans are burning fossil fuels, that threshold will be reached in not a hundred, but  in 13 years.

There are approximately 2,500 billion tons of carbon fuel still in the ground. Energy companies reserve assets are counted as future earnings and are reflected on the projected balance sheets.  A spokesman for Exxon Mobil said: 'we are confident that none of our hydrocarbon reserves are now or will become ‘stranded''. A nice way of saying they have plans to dig them up somehow, as it is just business as usual.

 So, knowing what we know now, that the Earth has around a dozen years before we send the climate into a irreversible death spiral, the CEO's of the major energy companies must be asking their risk managers questions like this: " How much climate disruption can the world handle?" "When do we send the Government into a crisis mode where they shut down all of our energy producing revenue?" It's a nice way of saying "How much disruption can we cause and get away with?" "How many deaths are acceptable? One million? Ten million? One hundred million?"

This is an honest question. It is as honest as the report that emerged last Monday from climate scientists, which demonstrated that if Exxon Mobil keep their promise, then the planet will no longer function effectively. I thought that this would be Exxon’s posture. The company spent millions denying the science when it was still possible. I have always thought their business plan was to keep pouring carbon into the atmosphere. Exxon’s statements are easy to translate: “We are overheating the planet, we think we have the right to keep doing it, and we have the money to keep doing it.”

So with that information on the table, it’s time for action. We must start by bankrupting them. By  taking away the money that allows them to act with arrogance, while the planet’s scientists explained the impact of climate change on everything from crop yields to civil wars. Our day for reckoning is fast approaching. How we react to it will be our legacy for the future.

It's now increasingly recognised that the transition into the post-carbon era must involve not simply "adaptation" and "mitigation" – the stale buzzwords of bureaucracy - but entail radical transformation of our societies at multiple levels. Even the IPCC's forthcoming mitigation plan concedes: "Stabilising greenhouse gas concentrations will require large-scale transformations in human societies."

But perhaps no clearer manifesto for this transformation came from an unexpected editorial in the British Medical Journal, stating that: "The IPCC report shows the need for 'radical and transformative change.'… This is an emergency. Immediate and transformative action is needed at every level: individual, local, and national; personal, political, and financial." The editorial endorses the World Bank president's call for "divestment from fossil fuels and investment in green energy… If we are to avoid catastrophic climate change and bequeath a sustainable planet worth living on, we must push, as individuals and as a profession, for a transformed, sustainable, and fair world."