-- But fossil fuels are only part of the story. About 65 percent of the world's greenhouse gases come from burning coal, oil, and natural gas. But that still leaves 35 percent from "direct emissions." What does that include? Cutting down trees and tilling the soil, which churns up carbon dioxide into the atmosphere. It also includes methane leaks from landfills and mining, as well as methane emissions from cows and other livestock.
-- Homes and buildings are a larger source of emissions than transportation. Every now and again, some think tank will come out with some wonky ideas for updating building codes and making houses and offices more energy-efficient. Those proposals don't get as much attention as, say, fuel-economy standards. But if you want to curb emissions and tackle global warming, buildings need at least as much attention as cars and trucks.
Update: On a related note, here's a handy list and map of greenhouse-gas emissions broken down by country. The top five emitters are China, United States, India, Russia, and Japan.