A Climate of Truth: Why We Need It and How To Get It Mike Berners-Lee Cambridge Univ. Press (2025)

I had the privilege of hearing climate scientist Mike Berners-Lee talk about his latest book before it was published. To a packed lecture theatre, he laid out his thesis: an increase in truthfulness is more important than technological advances as a solution to climate change and the related threats facing humanity.

I could not stop thinking about this proposition. Was it really that simple, or was the author being unforgivably naive? What would the book have to say about the strange times we currently live in, variously described as post-truth¹ and the age of misinformation²? I went out of my way to get my hands on an advance copy — it was a compelling read.

How scientists can drive climate action: celebrate nature and promote hope

The first chapter lays out a clear-eyed and data-rich description of the polycrisis we find ourselves in. Berners-Lee takes us through the interlinked issues of climate, energy, population, food, biodiversity, pollution and disease. He sugar-coats nothing.

The book firmly pushes back on those who argue that we are making progress on climate change. It presents what science tells us we can expect with the temperature rises that are already baked in: collapsing crop yields, worsening fires and more floods. With emissions continuing to increase year on year, we are still accelerating into the problem rather than putting on the brakes.

Technology isn’t enough

How can this view of climate change be reconciled with the techno-optimist view that innovation is delivering sustained improvements for most people on our shared planet, and will solve our environmental problems, too?

Berners-Lee refers to techno-optimism as “the new face of climate denial”. He argues that, although we have the technical advances needed to tackle the polycrisis, these alone will never be enough. A good example is how efficiency gains tend to increase, rather than reduce, consumption. This well-understood ‘rebound effect’ is also known as Jevons paradox, after a nineteenth-century industrialist who noticed that more-efficient use of coal led to increased demand. A green transition requires that renewable energy replace fossil fuels rather than supplementing them. This is not happening.

Despite Berners-Lee’s rhetoric, he shares a lot of ground with data scientist Hannah Ritchie, whose excellent book Not the End of the World (2024) takes a techno-optimist position. They both think that a sufficiently high global carbon price is crucial for incentivizing a reduction in fossil-fuel use. And they both agree that we need a mechanism, such as cap and trade, to ensure that the poorest are not disadvantaged. Berners-Lee puts more emphasis on how to get there.

High price of deceit

His book peels back the outer layer of the polycrisis to discuss the drastic changes needed in equality, education, the media, politics, the economy and law. The argument is that living well in the Anthropocene — in which the physical limits to growth are undeniable — demands drastic changes to how society operates, but that the decisions needed will be made only if voters’ understanding isn’t obscured by deceit.

This brings us to the core of the polycrisis. Berners-Lee highlights three intersecting values needed for humanity to thrive in the Anthropocene: respect for the environment, respect for others and respect for the truth. The final few chapters focus on the most crucial lever: truth.

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The book presents a typology of deception. Outright lies are just the tip of the iceberg, with more-hidden forms such as misdirection, burying bad news and false impressions potentially doing just as much damage. He talks about how “enticing bullshit” propagates: sometimes owing to self-interested cynicism, but often owing to simply to wishful or uncritical thinking.