I recently attended a talk by Tim Lenton, founder of the Global Systems Institute at the University of Exeter in the UK, on the topic of tipping points: the positive ones that can accelerate decarbonisation towards meeting net-zero emission targets.
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What's important about tipping points, Lenton explains, is that if breached, they cause abrupt changes that are much harder to reverse. “I spent a lot of the past 20 years mapping out the bad tipping points in the climate system that we don't want to cross if we can avoid them,” he says.
These critical climate tipping points are often coupled in a way that makes each one likely to trigger the tipping of others, he explains. A loss of major ice sheets, for example, causes a significant amount of sea level rise, resulting in the reorganisation of ocean and atmospheric circulation, which changes weather patterns worldwide and leads to the loss of substantial parts of the biosphere.
Which is why we need to act decisively to decarbonise the global economy and limit global warming. And while this is happening, we are accelerating much too slowly. “That's why I want to talk about positive tipping points as our best hope of achieving the acceleration in change we need,” Lenton says.
Going back into history, he recounts the story about one of his distant relatives, Lillian Lenton, a suffragette who was imprisoned while fighting for women's voting rights. She was arrested for burning down the tea house in Kew Gardens in London. While on a hunger strike, she was force fed, and unfortunately, they put the feeding tube into her lungs and nearly drowned her.
She was rushed to a hospital, with the UK Government of the time trying to cover up what had happened. It was quickly realised that they were lying, though, which ultimately led to a profound social tipping point in public opinion against the then government and in favour of votes for women, Tim Lenton relates.
He goes on to cite the brave actions of Greta Thunberg, who, by deciding to skip school and protest outside the Swedish parliament, made it easier for more and more youngsters to defy their parents, governments and schools, and join the movement for more decisive climate action. Around the world, millions of people of all ages are now climate activists, marking a tipping point in public opinion. However, as Greta Thunberg would remind us, this only matters if we actually act in a way that changes our behaviours or the technologies responsible for greenhouse gas emissions so that we eventually eliminate them.
In terms of technological tipping points, Lenton displays a photograph of the Easter Parade on Fifth Avenue, New York City, in 1900, which depicts rows of horse-drawn carriages alongside a single early automobile. A second photograph, taken on the same day and the same street just 13 years later, shows the exact opposite; there is just one last person left in a carriage, while everybody else is in an automobile. “This shows a fundamental change in how people moved around in our cities, and it unfolded within a decade across US cities and continued to spread rapidly around the world,” he points out.
Through that transition, even a century ago, some 30% of these automobiles were battery electric. But the combustion engine prevailed, with the electric vehicle relegated to an inconvenient alternative. This is rapidly changing. Electric vehicles on Norway’s roads now outnumber those with combustion engines. This is primarily thanks to a few social activists and the pop band A-ha, who imported a converted electric Fiat Panda, which was used to publicise demands to the Norwegian government to incentivise the switch to clean electric transport. Within seven or eight years, the enabling conditions and attitudes that would lead to a tipping point were breached. Today, battery electric vehicles have entirely taken over the market in Norway, with over 95% of all new vehicle sales in 2025 being electric.
More electric vehicles mean more batteries are needed, and the costs decrease. This is a knock-on enabler of storage solutions for renewable energy generation, he explains. “We are entering an extraordinary future, where electricity will be cheaper than it's ever been, incentivising its use for other things, such as using excess renewable energy to heat or cool our homes or to make new fuels, such as green hydrogen.
Most importantly, we all have some agency in creating and reinforcing positive tipping point changes. As consumers, we can choose to purchase or adopt different technologies, buy more energy-efficient appliances, change our eating habits, decrease the amount of single-use plastic we buy and recycle as much of our waste as possible. In industry, we can double down on energy efficiency initiatives, invest in renewable energy solutions to minimise fossil-based demand from the grid, adopt more circular and resource-efficient processes, and encourage others to follow suit.
Much of this is already underway. We need to be bolder, though, not only because it's necessary, but also because the results are overwhelmingly positive.