Page 526 - Environment: The Science Behind the Stories

Responding to Climate Change A2
6.0
A1B
Today most of the world’s people recognize that our fossil fuel 5.0 B1
consumption is altering the planet that our children will inherit. Year 2000 constant concentrations
From this point onward, our society will be focusing on how 4.0 20th century
best to respond to the challenges of climate change. The good
news is that everyone—not just leaders in government and 3.0
business, but everyday people, and especially today’s youth— Global surface warming (°C)
can play a part in this all-important search for solutions. 2.0

Shall we pursue mitigation or adaptation? 1.0
0
We can respond to climate change in two fundamental ways.
One is to pursue actions that reduce greenhouse gas emissions, –1.0 Y2000
so as to lessen the severity of climate change. This strategy is B1 A1B A2
called mitigation because the aim is to mitigate, or alleviate, 1900 2000 2100
the problem. Examples include improving energy efficiency, Year
switching to clean and renewable energy sources, preventing Figure 18.24 The sooner we stabilize our emissions,
deforestation, recovering landfill gas, and encouraging farm the less climate change we will cause. The red line shows
practices that protect soil quality. temperature change we could expect if we were to limit our
The second type of response is to pursue strategies to cush- yearly carbon emissions to the level they were in the year 2000.
ion ourselves from the impacts of climate change. This strat- The blue, green, and yellow lines show the change expected
egy is called adaptation because the goal is to adapt to change. under scenarios of rapid, medium, and slow control of emis-
Erecting a seawall, as Maldives residents did with the Great Wall sions, respectively. The vertical bars show means and ranges of
of Malé, is an example of adaptation. Some people of Tuvalu year-2100 temperatures for each scenario. Predictions are based
also adapted, by leaving their island to make a new life in New on a large number of climate models. Data from IPCC, 2007. Fourth
Zealand (see Weighing the Issues, p. 519). Other examples of assessment report.
adaptation include restricting coastal development; adjusting
farming practices to cope with drought; and modifying water we burn to generate electricity: (1) encouraging conservation
management practices to deal with reduced river flows, glacial and efficiency (pp. 564–566) and (2) switching to cleaner and
outburst floods, or salt contamination of groundwater. renewable energy sources (Chapters 20 and 21).
Both adaptation and mitigation are necessary. Adaptation
is needed because even if we could halt all our emissions right Conservation and efficiency As individuals we all
now, the greenhouse gas pollution already in the atmosphere can make lifestyle choices to reduce electricity consumption.
would continue driving global warming until the planet’s sys- New energy-efficient technologies make it easier to con-
tems reach a new equilibrium, with temperature rising an esti- serve. Replacing standard light bulbs with compact fluores-
mated 0.6°C (1.0°F) more by the end of the century. Because cent lights reduces energy use for lighting by 40%. The U.S.
we will face this change no matter what we do, it is wise to Environmental Protection Agency’s Energy Star Program rates
develop ways to minimize its impacts. household appliances, lights, windows, fans, office equipment,
We also need to pursue mitigation, because if we do noth- and heating and cooling systems by their energy efficiency.
ing to diminish climate change, it will eventually overwhelm Replacing an old washing machine with an Energy Star wash-
any efforts we might make to adapt. To leave a sustainable ing machine can cut your CO emissions by 200 kg (440 lb)
2
future for our civilization and to safeguard the living planet that annually. Energy Star homes use highly efficient windows,
we know, we will need to pursue mitigation. The sooner we ducts, insulation, and heating and cooling systems to reduce
begin reducing our emissions, the lower the level at which they energy use and emissions by 30% or more. Such technological
will peak, and the less we will alter climate (Figure 18.24). We solutions also save consumers money by reducing utility bills.
will spend the remainder of our chapter examining approaches Manufacturers can make the same types of choices as
for the mitigation of climate change. consumers in their purchases, and can manufacture energy-
efficient products. Power producers can use approaches such CHAPTER 18 • Glob al Cli M aT e Chan G e
as cogeneration (p. 564) to produce fewer emissions per unit
We are developing solutions in electricity of energy generated.
generation
Sources of electricity We can also reduce greenhouse
From cooking to heating to lighting, much of what we do gas emissions by switching to cleaner energy sources. Natural
each day depends on electricity. The generation of electricity gas generates the same amount of energy as coal, with half the
produces the largest portion (40%) of U.S. carbon dioxide emissions. Cleaner still are alternatives to fossil fuels, includ-
emissions. Fossil fuel combustion generates 70% of U.S. ing nuclear power (pp. 573–584), bioenergy, hydroelectric
electricity, and coal accounts for most of the resulting emis- power, geothermal power, solar photovoltaic cells, wind
sions. There are two ways to reduce the amount of fossil fuels power, and ocean sources. These energy sources give off no 525

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