Spewed high into the atmosphere, carbon emissions from plane travel are twice as damaging to the environment as those that originate on the ground.

More than 80 percent of CO2 emissions worldwide stem from fossil-fuel consumption (driving and flying) and energy use (cooling and heating your home).

Because huge amounts of energy are used to raise, feed, medicate, and transport livestock, vegetarians usually have lower carbon footprints than meat eaters.

Since the 1700s, the total atmospheric load of CO2 has increased by 35 percent.