The forecasts that global warming will cost society billions are everywhere. More than it costs to prevent it (even ignoring the human price). Economists debate the numbers but not the principle.

After the financial costs come all the social, natural, aesthetic, moral and ethical losses that have no monetary price – the quality of everyday life. Climate change-induced floods, forest fires, droughts, extreme weather and rising sea levels will remorselessly degrade the fabric of our society.

If self-interest were not enough, there are several moral and ethical arguments to be made too.

Main leaders at Paris COP 2015 raise hands in celebration as deal signed

At the Paris Climate Convention in 2015, world leaders agreed to make their best efforts to limit average global temperature rise to 1.5°C. This was because the science was clear that (a) CO2 from human activities was causing the rise, (b) anything higher than 1.5°C would most likely be very bad news for everyone and (c) the 22 oceanic small island states would most likely be lost to sea level rise, while the rest of the world suffers a range of other catastrophes.

That is to all intents and purposes the equivalent of a firm promise that we will not abandon our future to the effects of society’s over-exploitation of fossil fuels – although political leaders are not well-known for keeping promises.

While the citizens of the developed world consider a future of fires, floods and rising seas, more dire still are the expected impacts on subsistence farmers in developing nations – the world’s poorest and most innocent of CO2 emissions:

Failing to cut your emissions is like taking a bulldozer and razing the crops of a subsistence farmer in Africa. If you did that, everyone would agree it was wrong, but the greenhouse gases you are responsible for have the same result. The fact that the cause is invisible gases, and the effect maybe felt in the distant future, doesn’t allow each and every one of us to escape the moral obligation to act.

Peter Singer, Professor of Bioethics and renowned philosopher, Princeton

Lastly there is a moral obligation to our own younger and future generations. The inter-generational injustice of a global climate disaster is easily ignored since there are no laws to remedy it, but anyone whose ethical compass is more or less well-aligned will know the principle and the sense of shame that goes with it.

Greta Thunberg’s address to the 2019 New York UN Climate Summit clarifies the issue.