In response to the heatwave that set a new Australia-wide record on 7 January, when the national average maximum reached 40.33°C, the Bureau of Meteorology issued a statement that, on reflection, sounds the death knell for all of the social sciences taught in our universities.

“Everything that happens in the climate system now”, the manager of climate monitoring at the Bureau said, “is taking place on a planet which is a degree hotter than it used to be.”

Eminent US climate scientist, Kevin Trenberth, made the same point more fully last year:

The answer to the oft-asked question of whether an event is caused by climate change is that it is the wrong question. All weather events are affected by climate change because the environment in which they occur is warmer and moister than it used to be.

Trenberth’s commentary calls on us to reframe how we think about human-induced climate change. We can no longer place some events into the box marked “Nature” and some into the box marked “Human”.

The invention of these two boxes was the defining feature of modernity, an idea founded on Cartesian and Kantian philosophies of the subject. Its emergence has also been tracked by science studies in the contradiction between purified science and the messy process of knowledge creation, leading to Bruno Latour’s troubling claim that the separation of Human and Nature was an illusion, and that “we have never been modern”.

Climate science is now telling us that such a separation can no longer be sustained, that the natural and the human are mixed up, and their influences cannot be neatly distinguished.

This human-nature hybrid is true not just of the climate system, but of the planet as a whole, although it would be enough for it to be true of the climate system. We know from the new discipline of Earth system science that changes in the atmosphere affect not just the weather but the Earth’s hydrosphere (the watery parts), the biosphere (living creatures) and even the lithosphere (the Earth’s crust). They are all linked by the great natural cycles and processes that make the planet so dynamic. In short, everything is in play.

Apart from climatic change, it is apparent that human activity has transformed the Earth in profound ways. Every cubic metre of air and water, every hectare of land now has a human imprint, from hormones in the seas, to fluorocarbons in the atmosphere and radioactivity from nuclear weapons tests in the soil.

Each year humans shift ten times more rock and soil around the Earth than the great natural processes of erosion and weathering. Half of the land surface has been modified by humans. Dam-building since the 1930s has held back enough water to keep the oceans three centimetres lower than otherwise. Extinctions are now occurring at a rate 100 times faster than the natural one.

So profound has been the influence of humans that Earth scientists such as Will Steffen have recently declared that the Earth has entered a new geological epoch, an epoch defined by the fact that the “human imprint on the global environment has now become so large and active that it rivals some of the great forces of Nature in its impact on the functioning of the Earth system”. Known as the Anthropocene, the Age of Humans, it marks the end of the Holocene, the 10,000-year period of remarkable climatic stability and clemency that allowed civilisation to flourish.

The modern social sciences — sociology, psychology, political science, economics, history and, we may add, philosophy — rest on the assumption that the grand and the humdrum events of human life take place against a backdrop of an inert nature. Only humans have agency. Everything worthy of analysis occurs in the sealed world of “the social”, and where nature does make itself felt – in environmental history, sociology or politics – “the environment” is the Umwelt, the natural world “over there” that surrounds us and sometimes intrudes on our plans, but always remains separate.

What was distinctive of the “social sciences” that emerged in 18th-century Europe was not so much their aspiration to science but their “social-only” domain of concern.

So the advent of the Anthropocene shatters the self-contained world of social analysis that is the terrain of modern social science, and explains why those intellectuals who remain within it find it impossible to “analyze” the politics, sociology or philosophy of climate change in a way that is true to the science. They end up floundering in the old categories, unable to see that something epochal has occurred, a rupture on the scale of the Industrial Revolution or the emergence of civilization itself.

A few are trying to peer through the fog of modernism. In an epoch-marking intervention, Chicago historian Dipesh Chakrabarty has argued that the distinction we have drawn between natural history and human history has now collapsed. With the arrival of the Anthropocene, humans have become a geological force so that the two kinds of history have converged and it is no longer true that “all history properly so called is the history of human affairs”.

E.H. Carr’s famous definition of history must now be discarded:

History begins when men begin to think of the passage of time in terms not of natural processes — the cycle of the seasons, the human life-span — but of a series of specific events in which men are consciously involved and which they can consciously influence.

From hereon our history will increasingly be dominated by “natural processes”, influenced by us but largely beyond our control. Our future has become entangled with that of the Earth’s geological evolution. As I argue in a forthcoming book, contrary to the modernist faith, it can no longer be maintained that humans make their own history, for the stage on which we make it has now entered into the play as a dynamic and capricious force.

And the actors too must be scrutinised afresh. If on the Anthropocene’s hybrid Earth it is no longer tenable to characterise humans as the rational animal, God’s chosen creatures or just another species, what kind of being are we?

The social sciences taught in our universities must now be classed as “pre-Anthropocene”. The process of reinventing them — so that what is taught in our arts faculties is true to what has emerged in our science faculties — will be a sustained and arduous intellectual enterprise. After all, it was not just the landscape that was scorched by 40.33°C, but modernism itself.