Page 570 - Environment: The Science Behind the Stories

natural gas. Drilling in Florida waters would create jobs bring. Others are fearful that oil leaks from the pipe-
for Florida citizens as well as revenue for the state in the line could contaminate the water supply. Some of your
form of royalty payments from oil and gas companies. town’s landowners are looking forward to receiving pay-
However, there is always the risk of a catastrophic oil spill, ments from TransCanada for use of their land, whereas
with its ecological, social, and economic impacts. Would others dread the prospect of noise, pollution, and trees
you support or oppose offshore drilling off the Florida being cut on their property. If the company receives too
coastline? Why? What, if any, regulations would you insist much local opposition it says it may move the pipeline
be imposed on such development? What questions would route away from your town. What information would
you ask of scientists before making your decision? What you seek from TransCanada, from your state regula-
factors would you consider in making your decision? tors, and from scientists and engineers before deciding
6. THINK IT THROUGH You are the mayor of a rural whether support for the pipeline is in the best interest of
Nebraska town along the route of the proposed Keystone your town? How would you make your decision? How
XL pipeline extension. Some of your town’s residents might you try to address the diverse preferences of your
are eager to have jobs they believe the pipeline will town’s residents?

Calculating Ecological Footprints

Scientists at the Global Footprint Network calculate the energy Assume that you are an average American who burns about
component of our ecological footprint by estimating the amount 6.3 metric tons of oil-equivalent in fossil fuels each year and
of ecologically productive land and sea required to absorb the that average terrestrial net primary productivity (p. 129) can be
carbon released from fossil fuel combustion. This translates expressed as 0.0037 metric tons/ha/year. Calculate how many
into 4.9 ha of the average American’s 7.2-ha ecological foot- hectares of land it would take to supply our fuel use by present-
print. Another way to think about our footprint, however, is day photosynthetic production.
to estimate how much land would be needed to grow biomass
with an energy content equal to that of the fossil fuel we burn.

Hectares of land for fuel 2. Earth’s total land area is approximately 15 billion
production hectares. Compare this to the hectares of land for fuel
You 1703 production from the table.
3. In the absence of stored energy from fossil fuels, how
Your class
large a human population could Earth support at the level
Your state
of consumption of the average American, if all of Earth’s
United States area were devoted to fuel production? Do you consider
this realistic? Provide two reasons why or why not.
1. Compare the energy component of your ecological foot-
print calculated in this way with the 4.9 ha calculated CHAPTER 19 • FOSSIL FUELS, THEIR IMPA CT S, AND ENERGY CONSERVATI ON
using the method of the Global Footprint Network.
Explain why results from the two methods may differ.

STUDENTS INSTRUCTORS
Go to MasteringEnvironmentalScience for assignments, the Go to MasteringEnvironmentalScience for automatically
etext, and the Study Area with practice tests, videos, current graded activities, current events, videos, and reading questions
events, and activities. that you can assign to your students, plus Instructor Resources.

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