True or False? The Keeling Curve was one of the first graphs showing how CO2 levels are increasing.

Here are the answers to your questions:

• 2. True or False? The Keeling Curve was one of the first graphs showing how CO2 levels are increasing. The Keeling Curve, initiated in 1958, is indeed one of the most significant and earliest continuous measurements demonstrating the increase in atmospheric carbon dioxide levels.

  • True

• 3. The ideal concentration of carbon dioxide to return the earth's temperature to pre-industrial levels is: Pre-industrial atmospheric carbon dioxide concentrations were approximately 280 parts per million (ppm).

  • 280 parts per million