In October 2018 the Intergovernmental Panel on Climate Change (IPCC) issued a stark warning: enact urgent measures to limit global warming within the next 12 years or irrevocably deplete the ecosystems that sustain human life on Earth.

By way of remedy, the IPCC recommends that we reduce carbon dioxide (CO2) and other greenhouse gas emissions (GHG) to ‘net zero’ by 2050. This trajectory would give us a chance to limit warming to a maximum of 1.5 degrees Celsius — no defence against the accelerating impacts such as extreme wildfires, heatwaves, and hurricanes, which are already upon us.

But what if we aimed to cut absolute carbon emissions to zero by 2025? No-one knows if it’s possible, but it’s instructive to imagine how such a scenario would play out. There are only two ways to go about this: ramping up clean energy generation via renewable power, while simultaneously massively reducing the energy we use.

Under a zero-carbon scenario, the fossil-fuelled energy sector, which generates around 80% of global emissions, would be phased out fast: coal, oil, gas. Meanwhile, all heating and transport would have to be weaned off carbon-based fuels on to clean electricity.

With the tight timescale ruling out new nuclear reactors, the entire world’s productive effort would be channelled into a logistical feat unknown in human history: building new solar, tidal, wind and hydro generation while modifying electricity grids; and a monumental efficiency drive in homes and businesses. Zero Carbon Britain suggests building 130,000 100-meter tall wind turbines to power the UK (in an area over twice the size of Wales), while Zero Carbon Australia proposes 12 concentrating solar plants over 2,760km2 (an area the size of Kangaroo Island).

By 2025, renewables — currently supplying 10% of global energy consumption — won’t come close to meeting current demand. So, our zero-carbon scenario requires the global elite (the 20% of global citizens who account for 70$ of emissions) to cut the quickest and deepest. Setting aside climate justice concerns, concentrating on US citizens who average 16.4 tonnes CO2 per person, would bring us closer to zero a lot quicker than the people of Niger, who clock up under 0.1 tonne.

In the rich world, in particular, zero-carbon would usher in a period of huge social change. Energy would be stringently rationed, dedicated to the survival and essential activities; we’d go to bed early and rise with the sun. Expect massive disruption in the way food is grown, processed and distributed — more turnips, fewer mangoes on the menu in the UK for starters. Globally, there would be much-reduced private car use, virtually no aviation, haulage or shipping — spelling a dramatic end to material globalization as we know it.

But how to enact change on this scale? To avoid a totalitarian, ‘eco-fascist’ dystopia, a zero-carbon plan delivered at this rate would need to be contingent on total buy-in, perhaps triggered by a sooner-than-expected suite of apocalyptic impacts such as the collapse of pollinating insects, severe typhoons and salt-water flooding.