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Table 3

Population at Risk in 2085 for Water Stress

Population at Risk in the

Additional Population at

Total Population

Absence of Climate Change

Risk Because of Climate Change

at Risk

Units

Millions

Percentage of

Millions

Percentage of

Millions

Percentage of

Global Population

Baseline 1990

1,368

25.8

1,368

25.8

A1FI 2085

2,859

36.2

1,192

15.1

1,667

21.1

A2 2085

8,066

56.8

2,100 to 0

14.8 to 0

5,966 to 8,066

42.0 to 56.8

B2 2085

4,530

44.4

937 to 104

9.2 to 1.0

3,593 to 4,634

35.2 to 45.4

B1 2085

2,859

36.2

634

8.0

2,225

28.2

Source: N. W. Arnell, "Climate Change and Global Water Resources: SRES Emissions and Socio-Economic Scenarios," Global Environmental Change 14,

no. 1 (2004): p. 41, Table 8.

sector could go a long way toward ensuring

Moreover, the Long et al. study justified its

that hunger does not increase in the future.

low estimate of the fertilization effect by argu-

Finally, the estimates provided in Table 2

ing that nitrogen usage per hectare is lower in

indicate that in order to compare the conse-

the developing world than in the Organization

quences of various scenarios, it is insufficient

for Economic Cooperation and Development.

to examine only the impacts of climate

Although that might be true today, increased

change. One should also look at the total level

use of nitrogen is precisely the kind of adapta-

of hunger. Otherwise, based merely on an

tion that would become more affordable in the

examination of the population at risk from

future as countries, even developing countries,

climate change alone, one could conclude,

become wealthier. Indeed, this is one of the

erroneously, that, with respect to hunger, A2 is

autonomous adaptations allowed under the

FTA study.34 In addition, the development of

the best of the four worlds examined. But,

based on either the total population at risk or

crops that would be drought-resistant and/or

the proportion of the global population at

utilize nitrogen more efficiently is among the

more active areas of crop research.35

risk, A2 would be the worst of the four scenar-

ios for hunger. This also illustrates that efforts

While the contribution of climate change

focused on minimizing the consequences of

to the total population at risk from hunger in

climate change to the exclusion of other soci-

2085 seems large (21 percent), it results from a

etal objectives might actually reduce overall

small (2 percent) warming-related drop in

human welfare.

future global food production between 1990

and 2085.36 In other words, unmitigated

Water Stress

warming would reduce the annual growth in

The FTA's estimates of the population at

food productivity from 0.84 percent per year

risk for water stress in 2085 with and without

to 0.82 percent per year. This suggests two

climate change are shown for each scenario in

things. First, a small decline in the rate of pro-

Table 3.38 A population is deemed to be at risk

ductivity growth--perhaps "forced" by the

if available water supplies fall below 1,000 m3

assumption that no new technologies will

develop autonomously to adapt to climate

per capita per year. The populations at risk in

change--would lead to disproportionately

Table 3 reflect the fact that, because of cli-

large effects in terms of the population at risk

mate change, some populations will move in

from hunger.37 Second, a small boost in annu-

and out of the water stressed category.

Table 3 clearly demonstrates that the

al productivity of the food and agricultural