How many deaths does climate change have to cause before someone takes responsibility? Our current use of fossil fuels has “potentially catastrophic effects for human health and human survival”, according to a major new report released on Tuesday by medical journal the Lancet and University College London. And it’s not as if we still have time before climate change starts to bite.

As long ago as 2009, Kofi Annan’s Global Humanitarian Forum estimated that there were already 300,000 deaths a year from additional heatwaves, floods, droughts and forest fires attributable to global warming – a total which would rise to 500,000 a year by 2030. The Madrid-based climate change watch group Dara and the Climate Vulnerable Forum put deaths at about 400,000 a year, increasing to 600,000 by 2030. And last year the World Health Organisation estimated that the number of deaths from just the additional burden of disease and heatwaves would be 250,000 a year between 2030 and 2050.

If such figures are right, and the annual human cost of climate change is already around 100 times greater than that of the 9/11 attack on the World Trade Center, the inaction of our governments looks bizarre. Estimates suggest that current national pledges to reduce carbon emissions by 2020, submitted in preparation for the UN’s climate change conference in Paris in December, will delay the arrival of more dangerous climate change by only two years – from 2036 to 2038. The number of deaths from climate change will continue to rise, but just a little bit more slowly.

During the 200 years since the beginning of industrialisation, the concentration of carbon in the air has increased from 280 to 400 parts per million, a rise of more than 40%. Human beings have never breathed such high levels of carbon, and the world is now more likely to be heading for a 3-4C rise in temperature rather than the 2C maximum thought safe. Yet international agreements to cut carbon emissions are still stymied – partly by the tactics of fossil fuel companies and partly by the lack of trust between developed and developing nations. In her book This Changes Everything, Naomi Klein has documented how oil and coal companies have successfully deployed every kind of delaying tactic, including penetrating environmental campaigning groups, buying politicians and misrepresenting climate science. From the health effects of smoking, to food standards and the safety of pharmaceuticals, such tactics have become familiar whenever the pursuit of profit conflicts with the public interest.

Naomi Klein on tackling climate change and inequality - video Guardian

Even now, the major oil companies cannot agree on whether to support a carbon pricing system: BP and Shell are for it, but Exxon Mobil and Chevron are against.

In this situation, you might expect governments to sue the fossil fuel companies and claim damages on behalf of their citizens, but it seems that the boot is firmly on the other foot. Large corporations are increasingly suing democratically elected governments that pass laws or impose regulations that may be detrimental to commercial interests. With international investment agreements in place, multinationals have won hundreds of millions of pounds in compensation from governments imposing regulations designed simply to protect the environment. And this situation is going to get a whole lot worse if the Transatlantic Trade and Investment Partnership (TTIP) goes ahead. It will allow the corporate coach and horses to ride roughshod over democratic governments.

Is it possible to imagine a mass movement ever turning this round and reasserting the primacy of democratic control and the public interest over the pursuit of profit? Perhaps. This newspaper’s campaign to get institutions to divest from fossil fuel companies is gaining adherents, and is an important start.

Another promising strategy has been proposed by Professor Robert Costanza and Dr Ida Kubiszewski, both ecological economists at the Australian National University in Canberra. They argue that one way of gaining leverage in this situation would be to create an Earth Atmospheric Trust. Given that the atmosphere is a community asset which serves all of us, we need to use the public trust doctrine (outlined by Mary Wood in her book Nature’s Trust: Environmental Law for a New Ecological Age) to assert ownership through a public trust. The public trust doctrine exists in many countries with legal systems derived from Roman law and has been used to protect common natural resources such as water sources, shorelines and wildlife for public benefit. Because the atmosphere is a global asset, we would need governments to act as co-trustees with a duty to protect the air and take action against those who pollute it.

Legal action for damages would have to start with the 90 fossil fuel companies that are estimated to be responsible for two-thirds of all carbon emissions. Just as BP was required to pay damages after the Deepwater oil spill in the Gulf of Mexico, so these companies would have to pay for the spillage of carbon into the atmosphere which their products cause. Based on average estimates, damages might be set at $125 per ton of carbon. Proceeds should be used to fund the transition to renewable energy sources.

It will take carefully planned popular pressure to weaken corporate opposition and push governments into acting on our behalf. To get this moving, Costanza and Kubiszewski propose a campaign to “Claim the Sky” as a public trust on behalf of global society. You can support it by signing up on Avaaz. Together we can campaign to invoice fossil fuel companies for the damage their intransigence causes.