On Monday, July 20, 2015 at 12:59:45 PM UTC-4, Dan Marotta wrote:
In 1804 the population of the earth was 1 billion people.* It took
123 years to add another billion, then 33 years, then 14, then 12 to
get the population up to 6 billion by 1999 (source).*
Now the human population is roughty 10.8 billion people (source)!



I don't suppose all those people blowing CO2 into the atmosphere has
anything to do with this?


Dan Marotta

That's a good question! The CO2 that people exhale is the product of
metabolism; the food that they eat is combined with Oxygen to produce
water, CO2, and energy. So, it's Carbon that was in the system to
start with.