Oil, the ultimate portable energy, has changed human history. Relatively soon, oil will go, changing history again.

Oil only supplies about a third of the world's energy: coal and natural gas supply about half. (Nuclear and renewables make up the modest balance.) Burning the three fossil fuels collectively produces about 30 billion tonnes of carbon dioxide each year.

If it's a conceptual hurdle to imagine these invisible tonnes forming a heat-trapping molecular blanket around the Earth, it's an an even greater feat to dismiss the decades of physics that call out man-made CO2 (and other gases) as a greenhouse gas.

The same principles of physics were used to create microwave ovens, satellite imagery, heat-seeking missiles, MRI scans and to calculate the composition of the atmospheres of other planets. In short, the physics work.

The only means of forecasting how real physics will play out in a theoretical future is to use computer modelling. Models, as modellers and critics alike are aware, are crude. But they can suggest trends.

What is probable, the models (and the physics) say, is that climate will become more variable and individual weather events more severe. The sort of weather, in fact, that has been increasingly dished up over the last decade, the warmest on the instrumental record.

None of this matters for the Earth: it's been here before. It matters for the people now crowded on the Earth, wedded to their immovable territories in the form of farms, towns and cities, and their dependency on agriculture—a method of creating food that relies on a degree of climatic stability.

It matters to Australians, who are used to extreme weather, but not the sort of extremes that wreck the foundations of our prosperity.

Nor is prosperity from fossil fuel exports unlikely to last long—not nearly as long as the fossil resources themselves. The world is moving toward renewables, a democratic form of energy that any country can generate. It may only take a few decades, or less, for coal to become dirty, old-fashioned, and cheap.

Mainstream Australian politics, driven by the reptilian brain of immediate survival, is yet to properly deal with the fact that fossil fuel dependency is taking us up a narrowing gully, a dead-end ahead and avalanches behind.

With a few notable exceptions within their ranks, the major parties are approaching the issue of de-carbonisation as something to win voters—i.e. politics—rather than the central issue for Australia's future—i.e. leadership.

Still, their carbon policies are all we have to work with. Rather than dwelling on the cynicism behind the policies, we need to ask what represents the best first step. What puts us on an alternative energy path fastest, with the least downside?

(Anything that works will involve some economic pain. No addiction is thrown without suffering.)

But more promising than the political process, I think, is what's happening well away from Parliaments. Across the agricultural landscape, I meet farmers who are finding new ways to farm that use less fossil energy, and capture any available energy more effectively, for more productivity.

Fact is, if you're working on the land over the next decade or two, and you're not thinking about energy—capturing, minimising, converting, storing or selling it—then your foothold on the land will be tenuous.

And this, more than anything, makes me optimistic that the next "normal" will be a buzz of farmer-driven innovation; a sort of rural take on the energy and creativity of Silicon Valley. With dirt under its fingernails.