Back in March the Energy Sector Management Assistance Program (ESMAP) hosted an event here at the World Bank titled ‘Rethinking the Future of Energy’. One of our speakers was Duncan Clark, co-author of a recent book on energy and climate change. I came across Duncan while doing background research on the concept of supply-side constraints to fossil fuel extraction. It seems increasingly clear to me that demand-side climate change mitigation is always likely to be patchy in coverage (both within an economy, and between different countries), costly to implement due to the sheer number of point sources and transactions involved (and therefore regulations and policies required), and too psychologically distant from the real culprit: the fossil fuels we extract from the ground in ever-increasing quantities. Aside from a couple of vague references in the literature, Duncan is the first serious proponent for a supply-side approach to constraining carbon dioxide (CO2) emissions that I’ve come across.