Page 702 - Environment: The Science Behind the Stories

Answers to A

Data Analysis Questions APPENDIX

Chapter 1 Thus, if there were 3000 grasshoppers, we would expect with about half below the action level for hazard miti-
300 rodents (300/3000, a 1:10 ratio). gation and half above the action level. Thus, your best
Fig. 1.4 The global ecological footprint today is roughly prediction would be a roughly 50% likelihood that the
1.5 planet Earths. The global ecological footprint half a Fig. 2 (SBS2) The mudflow substrate gained the high- new well would contain water above the action level for
century ago (1961) was roughly 0.75 planet Earths. This est species richness, as seen by the fact that its curve is hazard mitigation.
makes for a difference of 0.75 planet Earths, and it means highest on the graph in part (a). The maximum number of
that today’s footprint is twice the size of the footprint half species it had in any one year was 22 or 23, about 17–18 Fig. 7.14 Once direct spending and tax breaks are added
a century ago. years after the eruption. The pumice substrate showed the together to get total subsidies, fossil fuels received about
slowest increase in percent plant cover, as seen by the fact $72 billion, while renewable energy received about
Fig. 1.12 Of the nations shown in the figure, the United $13 billion in the United States during the period covered
States has the largest per capita footprint, and Afghani- that its curve is the lowest in the graph in part (b). by the graph. If we divide 72 by 13, we get 5.54. Thus,
stan has the smallest per capita footprint. The U.S. foot- Fig. 4.20 Note that the temperature curve is above the about $5.50 is spent on fossil fuel subsidies for every
print (7.2 ha) is 14.4 times larger than Afghanistan’s precipitation curve between July and September. High $1.00 that goes to renewable energy.
footprint (0.5 ha), because 7.2 divided by 0.5 equals 14.4. temperatures lead to increased evaporation. Thus, even
though precipitation is roughly average at this time, the
Fig. 1.13 Answers will vary. Red and orange areas expe- Chapter 8
rience more-than-average impact, green areas experience warm temperatures cause increased evaporation and thus
less-than-average impact, and yellow areas experience dry conditions. Fig. 8.4 By examining the key that links colors on the
average impact. map to growth rates, we see that red indicates the high-
est growth rates, and that Africa has the highest over-
Chapter 5 all growth rate of any region. Within Africa, nations in
Chapter 2 Fig. 5.6 The width of the arrows in each figure represents southern Africa have the slowest growth, followed by
magnitude, so the wider the arrow, the larger the value. nations in northern Africa, where rates of increase are
Fig. 1 (SBS1) Drawing a straight line through the slightly higher. Annual population growth rates are high-
clusters of points from 1960 to 2010 produces a down- For chemical energy, the widest arrow goes from pro- est in central Africa and typically are 2.25% or higher.
ward-sloping line that shows a decreasing trend in ducers to detritus. This means the largest directional flux
ocean radioactivity from cesium-137 over time. (This of chemical energy in the ecosystem is from producers Fig. 8.19 The best approach to answer a question such
is because input of radioactive cesium into the ocean to detritus. For nutrients, a comparison of arrow widths as this one is to draw a “best-fit” line through the points
was reduced once nations stopped conducting nuclear shows the flux from detritus to producers to be, by far, on the figure that minimizes the distance between each
weapons tests in the atmosphere.) Inputs of cesium-137 the largest. point and the line you draw. Doing this yields a line that
to the oceans from the Chernobyl accident did not signifi- Fig. 5.21 Reducing nitrogen through enhanced nutrient slopes downward from left to right, suggesting a nega-
cantly alter this downward trend, as radioactivity levels management programs costs $21.90 per pound, whereas tive relationship between total fertility rate and rate of
continued to decline following this “pulse” of increased a 1-pound reduction from forest buffers costs only $3.10. enrollment of girls in secondary school. This relation-
radioactivity. Similar dilution of radioactivity over time Dividing $21.90 per pound by $3.10 per pound shows ship makes sense— one would expect that as more girls
of the radioactive material released from the Fukushima us that we could keep about 7 pounds of nitrogen out pursue education, they delay childbirth and reduce the
Daiichi accident would therefore be expected, leading to of waterways with forested buffers for the same price as nation’s TFR.
continued declines in radioactivity from cesium-137 in a 1-pound reduction from using nutrient management
coming decades. programs.
Chapter 9
Fig. 2.20 Comparison of the two figures reveals that this
belt of intense earthquake and volcanic activity corre- Fig. 9.6 Following the white lines in the diagram inward
sponds closely to the subduction zones at the boundaries Chapter 6 from these three values to where they intersect brings us
of the tectonic plates that surround the Pacific Ocean. As Fig. 6.13 If resources were being used more intensively, to a point within the light turquoise area in the lower right
shown in Figure 2.16, convergent plate boundaries domi- then they would be depleted more quickly, so the resource portion of the triangle, within the region for “silt loam.”
nate the length of the ring of fire. Note that other locations (green) line would drop more steeply. Faster resource The soil in question is therefore silt loam.
that experience earthquakes and volcanic activity—such consumption would likely lead to faster generation of Fig. 9.17b Answers will vary. Consultation of the color
as Indonesia, Iran, Turkey, and southern Italy—are simi- food, industrial output, and population, so these three key will reveal percentage of no-till farming for each
larly located along convergent plate boundaries. lines (orange, red, and dark blue) would rise more steeply region.
at first, but then fall sooner and more steeply as resources
became depleted. The line for pollution (purple) would be Fig. 2 (SBS1) Conventionally plowed plots show
Chapter 3 expected to rise sooner and more steeply. slightly more carbon content than no-till plots at 40 cm
of depth. We know this because the data point for con-
Fig. 3.15 A human being has the highest rate of survival Fig. 6.18 The average U.S. citizen has just slightly
at a young age. As shown by the type I survivorship fewer happy life years, yet a far greater ecological foot- ventionally plowed plots is further to the right, closer to
curve, the vast majority of individuals survive during print, than the average Costa Rican citizen. In fact, the the vertical dashed line representing the carbon content
youth, and then mortality rates rise during older age. of natural (uncropped) soils. Thus the conventionally ANSWER S T O D ATA AN ALYSI S QUESTI ONS
U.S. ecological footprint is so high that it drags down plowed soils at this depth have retained more carbon
Fig. 3.18 Because exponential growth cannot last for- its Happy Planet Index score sharply, despite the gen- than the no-till soils—a result opposite to that seen in the
ever, we would expect that growth of the western U.S. eral happiness of U.S. citizens. As a result, the United shallowest soil depths. In reality, however, the values are
population of Eurasian collared doves will eventually States ranks 105th out of 151 nations in terms of this so close together, and the error bars show such substantial
slow down and that the population will reach carrying indicator. variation, that these two values may not actually differ
capacity. Thus the population growth graph for the west- with statistical significance.
ern United States would come to have a shape more like
the current Florida graph, showing logistic growth. Chapter 7 Fig. 9.20 In the diagram, arrows point from causes to
consequences. Thus, according to the diagram, the im-
Fig. 2 (SBS1) Based on the data in the graph, we can mediate cause of exposure of bare topsoil is the removal
predict that water in the well 5000 m from a drilling site of native grass. Likewise, the immediate consequence of
Chapter 4 would be very unlikely to contain methane, because all exposing bare topsoil is wind and water erosion. Four
Fig. 4.10 In the generalized example shown, there are 10 the existing data points in the vicinity of 5000 m are near arrows lead away from wind and water erosion to other
rodents for every 100 grasshoppers; therefore, we can say zero. For the well just 250 m from the drilling site, exist- items, so therefore wind and water erosion has four im-
there are 1/10 (or 1:10) as many rodents as grasshoppers. ing values at that distance range from zero to 65 mg/L, mediate consequences. A-1

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