Lauded internationally for reducing its coal dependency and cleaning up its economy, the United Kingdom’s energy transition has a dirty little secret: biomass. Misclassified as renewable and carbon free, tallying the biodiversity and environmental impacts of burning biomass depends on nuance: how tight the regulations are, how fast a forest can grow back, and how well you can tweak your numbers. Now the world leader in burning trees to make electricity, scientific evidence is piling up questioning biomass’ claims to climate neutrality. A new study by energy thinktank Ember, The Burning Question, alongside other ongoing citizen climate campaigns, demands London curtails future subsidies while tightening biomass’ dubious carbon loophole. L. Michael Buchsbaum reports.