It’s nice to have a big picture of the sources of GHG by sector of the economy as well as their underlying drivers, e.g., energy use and its sources. The following diagram updated for 2008 and assembled by the U.S. EIA sums it up nicely:
The “industrial” sector is the largest, emitting 2.5 million metric tons CO2 equivalent (MMT C02e).
In most sectors, CO2 as a source of GHG dominates other gasses such as methane.
As with all such diagrams, notes are detailed and follow at the bottom of this post (click to enlarge).