What Climate Experts Actually Know: Carbon Brief's 2026 Quiz Reveals the Gaps

Every year, Carbon Brief gathers some of the sharpest minds working on climate science and policy into a room — or at least onto a screen — and asks them questions they probably should know the answers to. The 11th annual Carbon Brief Quiz, which drew roughly 300 participants including scientists, civil servants, journalists, and climate experts, is not just a parlor game. It is a quiet diagnostic tool, revealing where collective knowledge is solid, where it is shakier than anyone would like to admit, and which corners of the climate conversation remain genuinely underlit even among the people paid to illuminate them.

The event's longevity matters. Eleven years of running the same format with a rotating cast of specialists creates something rare in science communication: a longitudinal record of what the informed public thinks it knows. The crowd that shows up for Carbon Brief's quiz is not a random sample. These are people who read the literature, attend the conferences, and write the briefings that filter upward to ministers and downward to the public. When they get something wrong, it is worth asking why.

There is a well-documented tension in climate science between the certainty of the physical science baseline and the genuine uncertainty that surrounds impacts, timelines, and policy effectiveness. The Intergovernmental Panel on Climate Change has spent decades refining its confidence language precisely because overstatement and understatement both carry costs. But quiz formats have a way of cutting through hedged language and forcing a binary: you either know the number or you don't.

What events like this tend to surface is a pattern familiar to anyone who studies expert cognition. Specialists are often highly calibrated within their own domain and surprisingly poorly calibrated just outside it. A climate modeler might nail questions about radiative forcing and stumble on land-use emissions data. A policy analyst might know every detail of the EU's carbon border adjustment mechanism and draw a blank on ocean heat content trends. The quiz, in this sense, is less a test of intelligence than a map of professional silos — and in a field where the whole point is understanding an interconnected system, silos are a structural vulnerability.

This is not a trivial observation. Climate policy increasingly requires people to reason across domains: connecting agricultural methane to food security to trade policy to public health. When the experts themselves are compartmentalized, the advice they give tends to be compartmentalized too, and the resulting policies can optimize one variable while inadvertently stressing another.

The Carbon Brief Quiz has run long enough to track something like a collective learning curve. Topics that stumped participants in earlier years — the relative warming potency of methane versus carbon dioxide over different time horizons, for instance, or the share of global emissions attributable to aviation — tend to become common knowledge as they receive sustained media and policy attention. The quiz, in a small but real way, helps set that agenda by signaling which facts the informed community treats as foundational.

The second-order consequence worth watching here is the feedback loop between expert literacy and public communication. Journalists and civil servants who attend events like this carry what they learn back into their work. A science correspondent who discovers a gap in their own knowledge about, say, carbon removal technologies is more likely to commission or write a piece that fills that gap for general readers. Civil servants who realize they have been operating on outdated emissions figures are more likely to flag the discrepancy in the next policy review. The quiz functions, quietly, as a recalibration mechanism for an entire information ecosystem.

That ecosystem is under more pressure than it has ever been. Climate coverage is expanding even as newsroom resources contract. The speed of the policy cycle — driven by extreme weather events, energy price shocks, and geopolitical realignments around fossil fuels — means that the gap between what scientists know and what decision-makers act on is being compressed in ways that are not always healthy. Speed favors the confident and the simple, which is not always the same as the accurate and the nuanced.

Carbon Brief's quiz will not fix that structural problem. But it does something underrated: it makes expertise feel fallible and therefore human, which is exactly the disposition that good systems thinking requires. The expert who knows what they don't know is more useful than the one who doesn't know what they don't know. As the climate system continues to deliver surprises that outpace even the more alarming model projections, that epistemic humility may turn out to be one of the most important professional skills in the field.