I’m no expert on Australian politics – I don’t know all the cross-currents that will determine this week’s balloting.

But I do know a fair amount about the climate crisis, having written the first book on the subject back in 1989. So I can say with confidence that if Australians want to play a serious role in fixing the greatest challenge we’ve ever faced, this may be about the last election where people retain enough leverage to make a real difference.

Global warming, after all, is a math problem: how quickly can we reverse the flow of carbon into the atmosphere? The Intergovernmental Panel on Climate Change, in its report last year, said that unless a fundamental transformation was fully underway by 2030, we stood no chance of meeting the targets the world set in the Paris climate accords. No matter what country you’re in, “fundamental transformations” don’t come overnight; if you want to dramatically trim carbon emissions in 2030, it means you better start in 2020.

That means that if Aussie politicians of all stripes are still passing around lumps of coal and fantasising about huge new coal mines, that’s not going to happen.

The good news is, if you want change, the timing couldn’t be better: the engineers have done their job so well that the cost of renewable energy just keeps falling. In much of the world it’s now the cheapest way to produce electrons (and that’s even without charging fossil fuel a penny for the damage it’s doing). That means we’re in a position to make truly fast strides in the right direction (especially those of us lucky enough to live on a continent washed by wind and bathed in the rays of the sun).

Not only that, but we’re in a “climate moment” around the globe. It’s been inspiring to watch the pictures on social media of young Australians joining the climate strikes now breaking out around the world; their British counterparts, and their older colleagues at Extinction Rebellion, were enough to convince the Tory-led British Parliament to pass a declaration of “climate emergency” last month. Even in Donald Trump’s United States the Green New Deal keeps gaining momentum – most of the Democrats vying to replace him are calling for a concerted response to an “existential risk”.

None of it will be easy, of course – the fossil fuel industry continues to flex its considerable muscle around the world, and nowhere more than Australia. Watching the environment minister forced to disregard obvious science and instead rubberstamp proposals for groundwater plans for the Adani mega-mine are just the latest reminder of how the barons of this eighteenth century technology dominate Canberra.

Reading that Tony Abbott bet $100 that the climate will not change over the next decade is the latest reminder of the pervasive intellectual dishonesty necessary to prop up the status quo. Australians literally watched hot water kill off huge swaths of the Great Barrier Reef in two years. Hell, you’ve watched wildfires wipe out suburbs in two hours.

A decade is an eternity in climate time now. We’ve wasted three decades since scientists first raised the warning – that’s guaranteed that we’ll have massive increases in temperature.It means we’ve run out of decades to waste, and hence of elections to waste. Every election matters – it registers who we are at a certain moment in history, and it sets the course of the next few years.

But this election will matter forever.