Meet MethaneSAT: the satellite circling Earth right now to track global emissions from methane: a highly potent, short-term greenhouse gas. Environmental advocate Millie Chu Baird details the heat-trapping side effects of a planet full of methane — and explains why understanding where it comes from and taking steps to reduce it is the single most important thing we can do to affect climate change in our lifetimes. (MethaneSAT is part of the Audacious Project, TED's initiative to inspire and fund global change.)