- Live Science -
For people who are looking for ways to reduce their "carbon footprint," here's one radical idea that could have a big long-term impact, some scientists say: Have fewer kids.
A study by statisticians at Oregon State University concluded that in the United States, the carbon legacy and greenhouse gas impact of an extra child is almost 20 times more important than some of the other environment-friendly practices people might employ during their entire lives - things like driving a high mileage car, recycling, or using energy-efficient appliances and light bulbs.
"In discussions about , we tend to focus on the of an individual over his or her lifetime," said study team member Paul Murtaugh. "Those are important issues and it's essential that they should be considered. But an added challenge facing us is continuing population growth and increasing global consumption of resources."
Reproductive choices haven't gained as much attention in the consideration of human impact to the Earth, Murtaugh said. When an individual produces a child - and that child potentially produces more descendants in the future - the effect on the environment can be many times the impact produced by a person during their lifetime.
A child's impact
Under current conditions in the United States, for instance, each child ultimately adds about 9,441 metric tons of carbon dioxide to the carbon legacy of an average parent - about 5.7 times the lifetime emissions for which, on average, a person is responsible.
The impact doesn't only come through increased emissions of carbon dioxide and other greenhouse gases - larger populations also generate more waste and tax water supplies.
Here you see it in black and white: life is not cheap to these people, it is a negative.