1. Until about 1950, levels of atmospheric CO2 had not exceeded what concentration over the previous 800,000 years?
300 ppb (parts per billion)
300 ppm (parts per million)
300 ppt (parts per trillion)
2. Today, the atmospheric concentration of CO2 is over
3. On a per molecule basis, which of the following gases has the highest greenhouse warming potential?
4. Which of the following gases has the greatest impact on the greenhouse effect?
5. The current level of Earth's albedo (reflectivity), expressed in watts of incoming solar radiation is about