Download Global Warming, CO2, and You

Global Warming, CO2, and You
INTRODUCTION
The economies of the industrialized world are dependent on fossil fuel. Coal, gas, and petroleum,
formed hundreds of millions of years ago by decaying plants and animals, have provided modern
people with a supply of stored energy from the sun. Fossil fuels have allowed us to move from a
society based primarily on energy from people and living plants and animals to one based on fossil
fuels. Special conditions that existed when coal, gas, and petroleum formed are not present now, so
they can no longer form in significant amounts, if at all. Furthermore, formation of fossil fuels is a
very slow process, too slow for replacement to keep step with current use.
Limited supplies are, however, not the only concerns. When fossil fuels are burned they
produce, among other pollutants, carbon dioxide, the principal contributor to the greenhouse effect.
About three-quarters of the anthropogenic (human-produced) emissions of carbon dioxide (CO2;)
to the atmosphere during the past 20 years is due to fossil fuel burning. The rest is predominantly
due to land-use change, especially deforestation (IPCC, 2001). The average annual release of
carbon from fossil fuels during the 1990s was 6.35 billion tons (Marland et al., 2003). As shown in
Figure P6.1, the ambient concentration of CO2 in the atmosphere has increased about 29% since
the beginning of the industrial revolution. The significance of this dramatic increase in ambient
CO2, is global warming (climate change) as depicted in Figure P6.2 on the greenhouse effect.
Many scientists believe that stabilizing the climate will require slashing worldwide CO2 emissions
in half. Because the planet's population is now more than 6 billion people, each person's rightful
share of CO2 emissions is about 1.3 metric tons annually. Experts estimate that Americans generate
20 metric tons of CO2 per capita each year, but the figure is misleading because it lumps together
government, industrial, corporate, and personal production of CO2.
165
1958
.66
72
80
88
96
02
Figure P6.1—Atmospheric Concentration of Carbon Dioxide (CO;) from 1958 to 2001.
This graph is based on data from the Mauna Loa Observatory in Hawaii—an ideal facility for
measuring undisturbed air—constituting the longest continuous record of atmospheric carbon
dioxide (CO2) concentrations available in the world. Note the steady increase of CO2. The seasonal
fluctuations correspond to winter (a high level of CO2) when plants are not actively growing and
absorbing CO2, and summer (low CO2), when plants are more active. In 2002, the CO2
concentration increased to an average of 373.1 parts per million by volume (ppmv). Sources:
Raven, P.H. and L.R. Berg. 2004. Environment. 4th ed. John Wiley & Sons, NY (p. 462) and
Keeling, C.D. and T.P. Whorf. 2004. Atmospheric CO; records from sites in the SIO air sampling
network. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information
Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, TN.
Data from Carbon Dioxide Research Group, Scripps Institution of Oceanography, University of
California (http://sio.ucsd.edu/).
Figure P6.2—Enhanced Greenhouse Effect.
Carbon dioxide (CO;) and other greenhouse gases accumulate, warming the atmosphere by absorbing some of the
outgoing infrared (heat) radiation. Some of this heat is transferred back to Earth's surface, warming the land and ocean.
Source: Raven, P.H. and L.R. Berg. 2004. Environment. 4th ed. John Wiley & Sons, NY (p. 463).
How much CO2 do you contribute through your personal daily activities? To make a rough
calculation of your emissions, follow the steps below. Be sure to keep track of your units.
1. Estimate the number of miles you drive per year and the average miles per gallon your car gets.
.miles/year divided by.
miles/gallon .gallons/year
Burning a gallon of gas produces 9 kilograms of CO2, so multiply the above total by 9 to get
your total CO2 emissions from driving.
gallons/year multiplied by 9 kg/gallon
.kg/year
2. Estimate the number of kilowatt-hours of electricity you used last year. Multiply the number on
your last electric bill by 12 to get an estimate for the year. If you don't have an electric bill use the
"Energy Requirements of Household Appliances" table and add the values for each appliance to
find your annual energy consumption for electrical appliances in kilowatt-hours per year. One
kilowatt-hour of electricity generated in a coal-fired power plant produces about 1 kg of CO2.
Nuclear energy is effectively free of CO2, but produces only 20% of the nation's electricity.
Assume 80% of your electricity comes from a coal-fired power plant.
.kilowatt-hours/year multiplied by 0.8 =
.kg/year
10. Using the Internet or library resources, what controversies exist concerning
global warming?
Energy Requirements of Household
Electrical Appliances (kilowatt-hours
TABLE
P6.3
consumed annually)
Air conditioner—860 (based on 1000
hours yr)
Humidifier—163
Electric blanket—147
Iron—60
Blender—1
Microwave—100
Broiler—85
Mixer—2
Clock—17
Radio—86
Clothes dryer—993
Shaver—0.5
Radio + CD player—109
Toaster—39
Clothes washer—103
Range+oven 596
Coffee maker—140
Hair dryer—25
Refrigerator w/defrost—1591
Window fan- 200
Dehumidifier—377
water heater 4219
Dishwasher—165
TV—320
Sewing machine—11
Fan(furnace) 650
Fan (circulating)—43
Hot plate—90
Freezer, 16.5ft3 w/automatic defrost—
1820
Vacuum cleaner—46
Frying pan—100
Sources: Department of Energy, 2004.
Heating pad—10
Waffle iron—20
Garbage
disposal—7
WAYS TO REDUCE CARBON EMISSIONS
What you can do
Reduction*
Tune up your car
120 kg
Drive a car with 30mpg instead of 20mpg
330 kg
Drive a car with 40 mpg
599 kg
Drive a car with 50 mpg
717 kg
Take a train rather than fly
4.5 kg/160 km
*Estimation based on driving 10,000 miles/yr.
WAYS TO SAVE ENERGY
What
you
can
do______________________________________Energy
Savings*
Improve insulation in your hot water heater
300 kW/yr
Switch from typical refrigerator/freezer to more
2000 kW/yr
energy-efficient model
Substitute 18-watt compact fluorescent bulb for a
170 kW/yr
regular 75-watt bulb for 8 hrs
*Every kilowatt-hour saved reduces carbon emissions by 0.2 kg.
References
Department of Energy (DOE). 2004. Office of Energy Efficiency and Renewable Energy.
Consumer information [Online]. Available at http://www.eere.energy.gov/consumerinfo/refbriefs/ec7.html (verified 9 lune 2004).
Intergovernmental Panel on Climate Change (IPCC). 2001. Climate Change 2001: The Scientific
Basis—Summary for Policymakers
Lyman, Francesca. 2001. The Greenhouse Trap by World Resources Institute: What We're Doing
to the Atmosphere and How We Can Slow Global Warming. A World Resources Institute
Guide to the Environment. WRI, Beacon Press.
Marland.-G.-, T.A. Boden.and R.I. Andres. 2003. Global, Regional, and National CO;, Ernis-• .. sionsT-In Trends: A
Compendium of Data on Global Change. Carbon Dioxide Information Analysts-Center, Oak Ridge National Laboratory,
U.S. Department of Energy, Oak Ridge, TN.