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Apply: Earth's changing climate


Carbon dioxide (COA2) is the main greenhouse gas causing climate change. Humans began emitting large amounts of COA2 during the Industrial Revolution, a period of development that started in the mid-1700s.
The graph below shows COA2 levels in the atmosphere before and after the start of the Industrial Revolution. Levels are given in units of parts per million, or ppm. In this case, ppm refers to the number of COA2 particles per million particles of air.
By about how many ppm did COA2 levels rise between the start of the Industrial Revolution and 2021?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi