Climate crisis: How positive tipping points could save the planet

Professor Tim Lenton may be best known for sounding the alarm about climate change in the early 2000s, but in 2024 he is optimistic about the future of the planet.

Why? Because he is pioneering research on “positive tipping points” – shifts in societies and economies that gain momentum so rapidly they become the new norm and, crucially, propel decarbonization to help avert catastrophic climate change.

For much of his career, Professor Lenton – a climate academic and director of the Global Systems Institute at the University of Exeter – has focused on what happens when small planetary shifts combine to cross a critical threshold, triggering irreversible change.

Frequent droughts in the Amazon rainforest and the loss of Arctic sea ice are among the better-known climate tipping points happening now, he says.

Now, Professor Lenton’s focus is on positive tipping points, or “super-leverage points”, which can speed up the shift to a net-zero future, to avoid irreversible climate tipping points.

He recently joined Robin Pomeroy for an episode of the World Economic Forum’s Radio Davos podcast to explain why he is hopeful we can win the climate battle.

The concept of positive tipping points is empowering for Professor Lenton because they are already happening – through the renewable energy and electric vehicles transition, for example – demonstrating that society can prevent catastrophic climate change.

“It's vital to shift away from a sense of climate doom because that's disempowering and just leaves us, I think, possibly paralysed by fear, but also by the complexity of the situation,” he says.

“Instead, it's really important to know that we can work with the beautiful, complex systems of the Earth, but also our societies and economy to accelerate the change we desperately need to avoid the worst of the climate and ecological crisis.

“What I'm trying to explain with the concept of positive tipping points is that we can all be part of accelerating the change.

“The crucial idea here behind the tipping point is that when reinforcing or amplifying feedback within a system gets so strong, it just keeps propelling change without you having to push the system anymore.

“And then we've got to ask, OK, what are those reinforcing feedbacks? And some of those are things – like the more we consume a product, the better the people in manufacturing get at making it – because there's all this learning going on all the time,” Professor Lenton explained.

“There's real, concrete data and evidence that the transition to renewable energy and electric vehicles (EVs), for example, are accelerating exponentially and have become self-propelling. So even if we withdrew some of the subsidies, incentives and other mandates that started the tipping, you wouldn't be able to stop it now.”

He says electricity generation in the United Kingdom, his home nation, is an example of a positive tipping point.

“We went from a situation in 2012 where 40% of the electricity we used was from burning coal to a situation, say 10 years later in 2020, to where it was down to 1% or 2%.

“Nobody noticed because they don't think about where the electricity comes from when they switch the light on. But it's been a very effective and rapid transition triggered by a really modest price on carbon emissions, specifically targeted just to the power sector.

Norway being “at least eight years ahead of the rest of the world in tipping its marketplace completely to EVs” is another example of a tipping point, Professor Lenton says.

“That is an exciting tale that begins with social activists, environmentalists who ultimately persuade, or you might say, shame the government into action. And then that intersects with an evolving technology and a global marketplace and manufacturing companies.”

He gave three examples of positive tipping points accelerating the race to stop climate change.

Approximately 14% of the world's primary energy is now sourced from renewable technologies. For every $1 spent on fossil fuels, $1.7 is now spent on clean energy.

“Electricity generation has passed a tipping point where renewable energy, solar or wind power is the cheapest form of power generation now in most of the world,” said Prof Lenton.

“And the uptake of solar and wind power is exponential in terms of the amount deployed, doubling pretty much every year or two.”

The share of EVs in global new vehicle sales has more than tripled in three years, from around 4% in 2020 to 14% in 2022, International Energy Agency data shows.

“That will tell you immediately that if it doubles to 20% and then to 40%, it'll only be a few years’ time, before 2030 I think, the market will be dominated by EVs,” said Prof Lenton.

Tipping points often combine in mutually reinforcing ways, he says, for example, the shift to renewable energy means EV batteries are getting cheaper.

“As we push towards 100% renewable electricity, we have to match electricity supply and demand,” he said. “When you put on the kettle, it isn't always when the sun is shining or the wind's blowing. So we need cheap storage of electricity and cheap batteries is a key form of that. So these two tipping points are reinforcing each other, and that's just one example of how things couple across sectors in reinforcing ways.”

Green ammonia is a form of ammonia, the fuel and fertilizer ingredient produced using renewable energy sources and without emitting carbon dioxide.

“Ammonia is crucial for fertilizer, but it also offers potential as an energy carrier and as a fuel, for example, for big ships in the ocean,” said Prof Lenton.

“Why is there a super leverage point there? Well, because there's a first market for green ammonia and that happens to be fertilizer, because the price of fossil-fuel fertilizer has been sky-high ever since the war in Ukraine.”

Opening up markets for new materials creates cascading feedback loops. As the number and size of factories increase, the next factory becomes cheaper to build – and the price of green ammonia falls.

“Bring down the price of those things to the point where green ammonia can then be cost-competitive as a shipping fuel, and that's another huge market. So we'll then scale up ammonia production even more, bringing down the price of green ammonia and green hydrogen yet further. Then it becomes cost-competitive for an even bigger market, which is to use green hydrogen to make steel in clean net-zero steel production.

“So it's a cascade of what we might call tipping points across sectors,” Professor Lenton added.

The motivation to keep pushing the message of positive tipping points couldn’t be bigger, he says: the survival of the human race.

“Well, it's absolutely clear to me as a climate scientist that we have to stop fossil fuel burning as soon as we can and limit what I call the cumulative emissions of greenhouse gases,” said Prof Lenton. “It's also absolutely clear that we're going nowhere near fast enough at doing that. We need to go at least five times faster in decarbonizing the economy, and the only credible way to do that now is through self-perpetuating exponential change, what I'm calling positive tipping points.

“So the whole motivation is to be researching what can trigger them sooner, is to avoid what I call the climate tipping points that are a source of existential risk to me, my kids, your kids, your grandkids, and all the generations to come.”

The Forum acknowledges the race against time to reduce the impacts of the climate crisis in The State of Climate Action: Major Course Correction Needed from +1.5% to −7% annual emissions. A comprehensive analysis of nations, corporations, technologies and financing, the whitepaper identifies steps that need to be taken to achieve climate action objectives.