Planet Health Report: AIR

What does carbon dioxide "parts per million" mean? And why is it important?

Carbon dioxide is a greenhouse gas. Too much carbon dioxide in the air makes Earth get warmer and warmer. When humans burn fossil fuels, like gasoline and coal, carbon dioxide is produced.

This number tells how many parts of carbon dioxide there are in one million parts of air. So, if carbon dioxide is at 390 parts per million (or ppm), that means in one million pounds of air there are 390 pounds of carbon dioxide.

We need to keep a close watch on this number. Carbon dioxide levels have gone sky-high in the past 100 years. Many scientists think that 350 ppm is a much healthier number and that we should try to reduce our use of fossil fuels to get that number back.

This graph shows how carbon dioxide levels have gone up and down for the past 650,000 years, but now have far exceeded any levels reached during this period.

Carbon dioxide levels have shot up since the beginning of the Industrial Age. Many scientists think we need to get the level of carbon dioxide in our atmosphere down to 350 parts per million or less. Ref.