Investment in climate action represents the defining economic growth opportunity of the 21st century, while fossil fuel–driven development is a dead end that leads to environmental and economic collapse, according to eminent economist Lord Nicholas Stern of the London School of Economics (LSE).

Stern, who authored the landmark 2006 Stern Review on the Economics of Climate Change, argued that the plummeting costs of clean technologies such as renewable energy and electric vehicles, combined with their capacity to create healthier and more productive societies, present a unique chance to tackle both the climate crisis and sluggish global growth. “Low-carbon growth is the only feasible longer-run growth on offer,” he said. “High-carbon growth self-destructs.”

In his forthcoming book, The Growth Story of the 21st Century: The Economics and Opportunity of Climate Action, set for release on 5 November, Stern outlines how rapid technological advancement has dramatically altered the economics of climate action since his 2006 review. The costs of solar power and batteries have fallen by around 80% over the past decade, with offshore wind costs down 73% and onshore wind down 57%. These advances, he said, demonstrate that the clean energy transition can drive productivity, job creation, and poverty reduction on a global scale.

“It’s a huge opportunity,” Stern said. “Cities where you can move and breathe are much more productive. The world desperately needs to increase the rate of growth, and climate action is the path to achieving it.”

Stern also reiterated that his earlier conclusion remains as valid — and even more urgent — today. “Every time you look at the science, it gets worse,” he cautioned. He pointed to new research suggesting that tipping points in the Earth’s climate system, once believed to occur at around 4°C of warming, may be triggered by a rise of just 2°C. “The effects of global heating are arriving faster and with greater severity than anticipated,” he said.

The economist was also critical of political leaders who continue to dismiss or downplay the climate crisis. Responding to former U.S. President Donald Trump’s claim that climate change is a “con job,” Stern said the science is clear and undeniable. “I’d say to Trump: ‘You’ve got children and grandchildren — think about the science, think about the risks,’” he said, warning that Trump’s own properties in Florida face growing threats from hurricanes and rising sea levels. “Solar already beats fossil fuels on electricity across most of the world, including large parts of the U.S. The good folk of Texas are investing in solar and wind because it’s cheaper than the alternatives,” he added.

Stern also directed his message to British political leaders, including Conservative leader Kemi Badenoch, who has pledged to repeal the Climate Change Act, and Reform UK leader Nigel Farage, who has called the UK’s net zero target “lunacy.” Stern urged them to “make an effort to understand the imperative for climate action and recognise the huge opportunities,” warning that “inaction is catastrophic.”

Recent analysis supports Stern’s optimism about green growth. In February, a study found that the UK’s net zero sector is expanding three times faster than the overall economy. The UK’s Office for Budget Responsibility reported in July that the cost of achieving the net zero target is now far lower than previously estimated, thanks to the rapid decline in renewable energy prices.

Despite his optimism about technological progress, Stern expressed concern about the political obstacles hindering climate action. “I am optimistic about what we can do but deeply worried about what we will do,” he said. “We’re trying to bring the rational argument to the table and help shape the politics around the world. But if political discourse remains so distorted that rational arguments cannot prevail, then we’re in for a very hard time.”

At its core, Stern’s message is both pragmatic and urgent: investing in clean energy and sustainable growth is not just a moral imperative but an economic necessity. As he put it, “It’s much better to invest in the technologies of the 21st century rather than those of the 19th and 20th.”