NPR asks the tricky question: Should we think about not having kids to reduce carbon emissions? Here are some of the lifetime (80 year) carbon savings they report:
Increase car's fuel economy from 20 to 30 mpg: 148
Reduce miles driven from 231 to 155 per week: 147
Replace single-glazed windows with energy-efficient windows: 121
Replace ten 75-watt incandescent bulbs with 25-watt energy-efficient lights: 36
Replace old refrigerator with energy-efficient model: 19
Recycle newspapers, magazines, glass, plastic, aluminum and steel cans: 17
Reduce number of children by one (with emissions fixed at 2005 per-capita values): 9,441
May the odds be ever in your favor.