Geology Reference
In-Depth Information
276
IV. Introduction to Sustainability: Resource Planning and Global Change
d.
About how much colder was the temperature during
the coldest parts of the glacial periods than during the
warmest part of the last interglacial?
TABLE 18.1 Approximate World Human Population,
1700-2005
Year
World Population (billions)
1700
0.660
1750
0.800
9. What might you infer (Figure 18.9) about the general rela-
tionship between CO
z
and temperature of the Earth in the
past?
1800
1.000
1850
1.300
1900
1.600
1930
2.000
10. From Figure 18.9
a.
What is the projected temperature variation in 2100?
1950
2.500
1960
3.000
1975
4.000
1990
5.300
b.
What is the projected CO2 level with "no controls" in
2100?
2000
6.100
2005
6.450
c. How does the projected temperature for 2100 compare
with the temperature during the height of the last inter-
glacial (125,000 years ago)?
7.
Given that the world's energy use and population con-
tinue to increase, over the next 10 years will the CO2 content
of the atmosphere (check one)
increase at its current rate
increase at a slower rate
increase at a more rapid rate
decrease
d.
If CO2 levels go beyond 700 ppm, what change, if any,
would you expect in temperature?
Why?
11.
The Third Assessment Report (TAR) in 2001 of the Inter-
governmental Panel on Climate Change (IPCC, 2001) pro-
vides an update on values in Figure 18.9. Highlights from
the Summary for Policy Makers include the following.
Projected concentrations of
atmospheric
CO2
for the
year 2100 range from 540 to 970 ppm compared with about
280 ppm for pre-industrial (pre-1750) values and about 368
ppm for the year 2000. These projections are based on popu-
lation, social, technical, and economic factors; however,
additional uncertainty arises when natural carbon removal
and climate feedback impacts are considered. The range
becomes 490-1250 ppm, which are increases of 75-350 percent
over the concentration in the year 1750.
TAR also looks at revised values for temperature.
Using the GHG projections and several climate models,
globally averaged surface temperatures
are expected to
increase by 1.4-5.8° C in the period 1990-2100.
Furthermore, the same report shows weakening in the
ocean thermohaline circulation
system; however, no mod-
els show a shutdown by 2100. That could occur beyond 2100
and would indicate a major climate threshold had been
passed. If local warming of 5.5°C occurred in Greenland for
1,000 years, this would add about 3 m to global
sea level,
a.
Given the above summary, what action should the world
take now (or in the future) in the way of long-range plan-
ning to address these climate changes? Consider several
responses in your point-form answer. If you opt for action
only in the future, indicate when you would take action.
8.
In 1997, the complex diagram (Figure 18.9), provided a
comprehensive summary of changes in past temperatures
and atmospheric CO2. The records extended from the pre-
sent, through the last ice age (Wisconsinan) and though the
last interglacial to 150,000 years before the present. These
data from the Vostok, Antarctica, ice core extend well
beyond the directly measured and earlier ice-core derived
temperatures of Figure 18.8. Use the information in Figure
18.9 to help answer the following questions.
a.
When was the lowest value for atmospheric
CO2?
What
was the value?
b.
In the 150,000 years prior to 1850, about when did the
highest atmospheric C0
2
occur? What was the CO2 value
at that time?
c.
What was the maximum temperature variation after
that peak in
CO2?
