1) The global CO2 emissions from fossil fuel burning are around 5.4 x 10⁹ metric tons. On a per capita basis Americans emit ~5.2 metric tons per person. By contrast, China, with 1 billion people, has per capita emissions which are about 1/10 of these. Calculate what China’s total emissions WOULD BE if they were to reach the same per capita emissions as the U.S.

 China’s total emissions would be _________________ metric tons.

 By what percent would the global fossil fuel CO₂ emissions increase if China were to achieve this level?

 The increase in the global fossil fuel CO2 emissions would be _______________%.

 2) Consider the following data:

 Complete the table assuming a constant growth rate for the next 30 years. (Hint: if you are unsure about the doubling time see your text, Ch. 6).

 3) In the upper atmosphere (stratosphere) ozone is continuously being destroyed and regenerated in a natural cycle:

Oxygen Û Ozone 

There is about 3.0 x 10¹⁵ grams of ozone present and about 1.1 x 10¹⁷ grams/year are produced. Assuming that this cycle is in balance, what is the average lifetime (in days) for a molecule of ozone in the stratosphere?

4) Consider the global cycle for element X below:

Atmosphere (20)

Land (50,000) ð Ocean (500)

The values in parentheses give the total burden of element X in that reservoir (in teragrams, 10¹² grams). Assume that system is in balance and that the fluxes:

Ocean Þ Atmosphere; AtmosphereÞ Land; and LandÞ Ocean are all equal to 10 teragrams per year. Calculate the average residence time (in years) for element X in each reservoir.

Residence time for element X:

Land _____________ years

Ocean _____________ years

Atmosphere _____________ years