A tipping point is a moment when a small change triggers a large, often irreversible, response.

Professor Tim Lenton, Director of the Global Systems Institute (GSI) at the University of Exeter, has previously warned the world is "dangerously close" to several tipping points that could accelerate climate change.

But in a new paper in the journal Climate Policy, Professor Lenton and Simon Sharpe, a Deputy Director in the UK Cabinet Office COP 26 unit, identify tipping points in human societies that could rapidly cut carbon emissions.

They highlight examples of such tipping points that have contributed to the world's fastest low-carbon transitions in road transport and power generation -- and say "small coalitions of countries" could trigger "upward-scaling tipping cascades" to achieve more.

"We have left it too late to tackle climate change incrementally," said Professor Lenton.

"Limiting global warming to well below 2°C now requires transformational change, and a dramatic acceleration of progress.

"For example, the power sector needs to decarbonise four times faster than its current rate, and the pace of the transition to zero-emission vehicles needs to double.

"Many people are questioning whether this is achievable. But hope lies in the way that tipping points can spark rapid change through complex systems."

The authors highlight two examples where policy interventions have already triggered pertinent tipping points at a national scale.

For each, they explain how further actions could turn these into "cascades" that change the global economy:

• Light road transport: Electric vehicles (EVs) account for 2-3% of new car sales globally. In Norway, this figure is more than 50% (ten times higher than any other country), thanks to policies that make EVs the same price to buy as conventional cars. A global tipping point will come when EVs cost the same to manufacture as conventional cars. A small number of key locations could help drive this change. China, the EU, and California are together responsible for half the world's car sales -- and each has targets to rapidly decarbonise their economies. Acting together, they could shift investment throughout the global industry, increasing EV production and decreasing costs, triggering a global tipping point to EVs. This in turn will make batteries better and cheaper, aiding decarbonisation in the power sector.
• Power: In recent years, the UK has decarbonised its power sector faster than any other large country. Tipping points have played a role. A carbon tax together with an EU emissions scheme made gas cheaper than coal. Combined with increasing renewable energy generation, this tipped coal into unprofitability and led to the irreversible destruction of coal plants. Globally, renewables are already generating electricity cheaper than fossil fuels in many countries. A tipping point could be reached when the cost of capital of coal plants falls below that of wind and solar in all countries. Decarbonising global power generation would in turn help accelerate decarbonisation of large parts of transport, heating and cooling, and industry.

These positive tipping cascades are by no means inevitable -- policies will be required to overcome the many barriers to transition.

But the beauty of tipping points is that thanks to reinforcing feedbacks, a relatively small number of initial actions could catalyse large changes at the global scale.

The paper encourages potential partners to work together to make these tipping cascades a reality.

"If either of these efforts -- in power or road transport -- succeed, the most important effect could be to tip perceptions of the potential for international cooperation to tackle climate change," Professor Lenton said.

The paper is entitled: "Upward-scaling tipping cascades to meet climate goals: plausible grounds for hope."

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Materials provided by University of Exeter. Note: Content may be edited for style and length.

Journal Reference:

1. Simon Sharpe, Timothy M. Lenton. Upward-scaling tipping cascades to meet climate goals: plausible grounds for hope. Climate Policy, 2021; 1 DOI: 10.1080/14693062.2020.1870097