Lisa Hymas contends that "the single most meaningful contribution I can make to a cleaner, greener world is to not have children."
The average American generates about 66 times more CO2 each year than the average Bangladeshi20 tons versus 0.3 tons. If you consider not just the carbon impact of your own kids but of your kids' kids and so on, the numbers get even starker. According to a 2009 study in Global Environmental Change [PDF] that took into account the long-term impact of Americans' descendants, each child adds an estimated 9,441 metric tons of CO2 to a parent's carbon legacythat's about 5.7 times his or her direct lifetime emissions.
And a people-free earth would not have human-caused climate change at all!