David Biello explains the relationship between birth control and climate change:
Overall, curbing population growth could reduce greenhouse gas emissions; reducing peak population to roughly 8 billion, for example, could save 29 percent of expected greenhouse gas emissions. Economic growth seems like one way to accomplish that, considering that rising wealth has historically slowed birth rates. But O'Neill and his colleagues warn that, if fewer but richer people consume more—as current consumption patterns in places like the U.S. suggest—those greenhouse gas savings become increased emissions.