Some time in the near future, perhaps as soon as this year, humans are likely to experience something that has never happened in modern history before.
For the first time, global emissions of planet-warming greenhouse gases might finally stop rising and head into long-term decline.
No one alive today has known a time like this. Nor has any other recent generation because, for most of the last 200 years, emissions have risen steadily on an upward path, interrupted only briefly when something like a financial crisis or pandemic causes a global economic shock.
The rate of this growth has been slowing globally, and emissions have now declined in more than 40 nations as countries become more energy efficient, switch from coal to cleaner gas and swap fossil fuels for renewables.
But this has yet to add up to a global fall in emissions. Once it does though, some analysts think the politics, psychology and even the financing of climate action could shift profoundly.
I have to say this thought did not occur to me in November, when research emerged showing that if today’s green energy growth trends continue, and if gases such as methane are cut, there is a 70 per cent chance that global emissions will start falling in 2024, making 2023 the year they peaked.
Then I started running into people like economist Nat Keohane, a former Obama White House adviser who is now president of the Center for Climate and Energy Solutions think-tank.
He is remarkably bullish about the impact of a global emissions decline. “I think that would be an extraordinarily powerful political and psychological moment,” he told me, adding that it could broaden the base of support for climate action in several ways.
First, it would be empowering because it would show that the fight against global warming was winnable, not a futile, pointless quest. I agree.
Second, a decline would offer concrete evidence that demand for fossil fuels was more fragile than appreciated, and competition in the global clean energy race more robust.
Keohane thinks this could shift the behaviour of governments, boardrooms and investors because it would make fossil fuel investments look more like a dead end, and green investments a competitive necessity.
I think this is possible too, but it would require a shift in the remorselessly short-termist thinking of investors, especially if the pace of emission declines was slow.
Also, those of us who live in countries like the UK, where emissions have nearly halved since 1990, know governments can easily use such achievements as an excuse to take their feet off the emissions-cutting accelerator.
As prime minister Rishi Sunak said last year, “it cannot be right” to burden working people with policies to cut emissions when “we’re so far ahead of every other country in the world”.
So would a global fall in emissions stop this line of argument?
Maybe not, but it would still dent the popular idea that it is pointless to virtuously cut emissions when China, the biggest emitter by far, is doing virtually nothing.
That’s because a global fall would be driven by drops in China, where surging wind and solar power growth has led some analysts to suggest fossil fuels are on the brink of structural decline in the power sector.
This, plus the prospect of soaring electric car sales dampening Chinese oil demand, are two reasons why the authors of the November research concluded a peak in emissions may be nearer than thought.
Their research has limitations, such as the assumption that emissions come down relatively smoothly across the world.
In practice, they might recede in China, the US and EU while Russia doubles down on fossil fuels, says one of the authors, Professor Joeri Rogelj, a frequent contributor to reports by the UN’s Intergovernmental Panel on Climate Change.
Also, even if emissions do start waning this year or next, they are unlikely to fall 43 per cent by 2030 from 2019 levels, which is what the Panel says is needed to keep the Paris Agreement’s 1.5C temperature goal within reach.
In other words, a global peak in emissions will be a big turning point, but not nearly enough to contain warming now hitting levels never recorded before. Years of steep and prolonged falls will be needed after that.
This is a big ask and, ultimately, no one knows for sure what sorts of behavioural shifts a peak might drive. But in a world of deepening climate gloom, any sign of hope is surely welcome.
pilita.clark@ft.com