Bill Gates lays out a plan to cut global carbon emissions to zero by 2050, delivered as a talk at TED2010. He argues the math of climate change comes down to a simple equation: total CO2 depends on population, services used per person, energy needed per service, and carbon emitted per unit of energy, and that last factor has to fall to near nothing. Getting there, he says, requires "miracles" in energy technology, and he walks through candidates including wind, solar, and biofuels before spending the most time on a project he personally backs: TerraPower's traveling-wave reactor, a nuclear design that runs on depleted uranium waste instead of enriched fuel. He sketches the reactor on a whiteboard, contrasts it with conventional plants, and addresses cost, safety, and waste concerns directly. The talk ends with a stated goal of demonstrating the new reactor design within roughly two decades. It is a policy and engineering argument built around one number, not a survey of environmental problems.