text: Lowering emissions has to do with greenhouse gas. Greenhouse gas is any gaseous thing in the atomosphere that is capable of absorbing radiation. It traps and holds heat to the atmosphere. If we lower greenhouse gas then it will prevent the earth from global warming. In source one, the writter says "Automobiles are the linchpin of suburbs and that, experts say, is a huge impediment to current efforts to dramatically reduce greenhouse gas emissions tailpipes." This line states that automobiles is becoming a hug problem because it uses gas and it causes greenhouse gas emissisions.