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Because Charles David Keeling and his colleagues began measuring CO2 in 1958, we now have an excellent record of how CO2 concentrations have changed in the atmosphere over time. From 1960 to 2010, the concentration of CO2 in the atmosphere increased from 320 to 390 ppm (parts per million).
Based on these two points in time, what has been the average annual increase of CO2 in the atmosphere?
Time = 2010 –1960 = 50 years
Increase in CO2 = 390 ppm –320 ppm = 70 ppm
Average annual increase in CO2 = 70 ppm ÷ 50 years = 1.4 ppm/year
Your Turn
If the annual rate of CO2 increase is 1.4 ppm, what concentration of CO2 do you predict for the year 2100?
From 2000 to 2010, the rate of increase grew to 1.9 ppm per year. Based on this faster rate, what concentration of CO2 do you predict for the year 2100?