Professor Will Steffen, 1947–2023

“Very few people around the world could claim to have done more to tackle climate change,” climate change minister Chris Bowen said of Australian climatologist Will Steffen last week. “He was a first class scientist and a world class communicator.”

This is an understatement. For decades Steffen, who was 75 when he died from cancer nine days ago, has stood tall among those extraordinary global citizens, including other notable Australians, who have dedicated their lives to understanding and communicating how human carbon pollution is affecting the climate.

After training as an atmospheric scientist in his native US, Steffen made Canberra his home in the 1970s. Around 2000 he cemented his reputation as a big-picture scientist when he helped to develop, along with Nobel laureate Paul Crutzen and others, the concept that we are now in a new, man-made geological epoch, the Anthropocene. 

That effort, plus work on Julia Gillard’s Climate Commission and then the crowd-funded Climate Council, shaped his last 20 years. At the end of what he had called a “critical decade”, in 2021 he wrote that Australian emissions in 2030 needed to be 75 per cent below the 2005 figure – approaching double the Albanese government’s “ambitious” 43 per cent.

This would be no consolation for him, but his effort to have human planetary impact registered on the formal geological timescale is bearing fruit. In 2021 the International Union of Geological Sciences acknowledged the substantial sedimentary record of current human activity by publishing a proposal to recognise the Anthropocene as a geological event.

The evidence for such an upheaval in the traditionally steady-state world of geological time was overwhelming when Steffen spoke to a Royal Society of Victoria audience last year. His typically thought-provoking presentation (it’s on YouTube) mapped our single species’ unprecedented global impact, which is now directing the evolution of all other species so profoundly that it constitutes a whole new stage of biosphere evolution.

“Never before in 4.5 billion years of Earth’s history – apart from the asteroid strike [that killed off the dinosaurs] 66 million years ago – have we seen temperatures rise like this,” he said. He said our current emissions trajectory was headed for a frightening warming scenario of ever more extreme weather events, species extinction and repeated crop failures.

Most frightening, he wrote last year, was the prospect of crossing “tipping points”, such as the collapse of ice sheets and the release of trillions of tonnes of natural carbon from forests and permafrost. Crossing those thresholds, he said, “may set off irreversible changes to the global climate system, and destroy critical ecosystems on which life on Earth depends.”

Such dire warnings didn’t come naturally to Steffen. He was one of nature’s gentlemen, a warm and generous man who gave freely of his time to help ordinary folk understand what is at stake. I won’t forget the afternoon he spent in a church hall on Hobart’s Eastern Shore a decade or so ago engaging with community members on finer points of climate science.

He repeatedly sought to get political and business leaders to see things his way. But if he had a blind spot, it was that he discounted drivers of human behaviour that did not in some way improve the common good. Power and profit and all the transactions they encompass – integral to how the political and business elite function – meant nothing to him.

Nearly all public discussions of economic wellbeing are about growth, about graphs going upwards. The climate crisis that so bothered Steffen needs those same graph lines to be going down. Unfettered growth was anathema to him – as it must be to anyone who offers more than a passing glance at our predicament – because of what it does to Earth’s natural systems.

In a conversation we once had, this affable, naturally optimistic man expressed his exasperation at politicians who kept closing their doors and ears to what he had to tell them. But he knew why they did. For those who pull our economic levers, the climate crisis looms as an insurmountable obstacle, potentially a career-killer. 

Steffen was a gifted scientist, a big-picture, wide-ranging thinker with a deep commitment to both humanity and the natural ecosystems that support it. His later life was dominated by a struggle to get behind the curtain of political and economic artifice that hides what is really happening to our planet. 

For me and many others his straight-talking was liberating, but for leaders it was threatening. Countering their fear and obfuscation is the great challenge for the world that Will Steffen leaves behind.

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