Multiple choice general knowledge science & technology

How much Carbon dioxide (CO2) is in Earth's atmosphere today?

  1. 10% or greater

  2. 2% to 10%

  3. less than 1/10th of 1%

  4. more than 25%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carbon dioxide currently makes up approximately 0.04% (420 ppm as of 2022) of Earth's atmosphere, which is less than 1/10th of 1%. This small percentage has a disproportionate effect on climate because CO2 is a potent greenhouse gas that has increased significantly from pre-industrial levels of about 280 ppm.

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