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Climate change is

late populations at risk into mortality proba-

at face value. An annual death rate of 0.17 mil-

bly overestimates the latter because it doesn't

lion would constitute 0.28 percent of global

unlikely to be the

mortality.57 Data from the WHO, however,

allow for increases in adaptive capacity due to

most important

both economic development and technologi-

indicates that climate change doesn't even

environmental

cal progress (or time). However, this would be

make the top 10 global health risk factors

consistent with the methodologies used in the

related to food, nutrition, and environmental

problem

impacts assessments in that they don't account

and occupational exposure. Specifically, the

confronting

for either new technologies for combatting

WHO attributes

hunger or increasing wealth and new tech-

human or

· 1.12 million deaths in 2001 to malaria;

nologies for treating malaria. In any case, both

environmental

· 3.24 million deaths to malnutrition;58

mortality without climate change and the

well-being.

· 1.73 million deaths to unsafe water, in-

increase in mortality due to climate change

alone should be overestimated to the same

adequate sanitation, and hygiene;

·

degree. Because impact analyses generally

1.62 million deaths to indoor air pollu-

underestimate changes in adaptive capacity,

tion from indoor heating and cooking

mortality estimates are probably overestimated

with wood, coal, and dung;

·

for each scenario, with larger overestimates for

0.8 million deaths to urban air pollu-

the wealthier scenarios.

tion; and

·

0.23 million deaths to lead exposure.59

Table 7 shows results for mortality with-

out climate change, the increase in mortality

due to climate change alone, and the sum of

Climate change is clearly not the most

the two in 2085 for each scenario. In order to

important environmental, let alone public

keep Table 7 simple, it shows only the mor-

health, problem facing the world today.

tality using the upper bound estimate for the

Is it possible that in the foreseeable future,

population at risk under each scenario.

the impact of climate change on public health

This table shows that for each scenario, the

could outweigh that of other factors? To shed

contribution of climate change to the total

light on that question, let's translate the pop-

mortality burden from malaria, hunger, and

ulations at risk in Tables 2, 4 and 5 for hunger,

coastal flooding is substantially smaller than

coastal flooding, and malaria into "ball park"

that due to other factors. The former varies

estimates for mortality assuming (1) that the

from 3.6 percent for the B2 scenario to 10.3

mortality scales linearly with populations at

percent for the A1FI scenario. Thus, if cli-

risk between 1990 and 2085, and (2) that there

mate change were halted at its 1990 level, it

has been no change in mortality for these

threats between 1990 and 2001.60

would reduce the mortality burden in 2085

from these three factors by no more than, for

Because Table 5 for malaria only has infor-

example, 10.3 percent for the warmest but

mation regarding the IS92a scenario, addi-

wealthiest A1FI scenario, corresponding to

tional assumptions are necessary to derive

237,000 deaths out of a possible 2,304,000.

mortality for each of the four standard scenar-

These results, in conjunction with those

ios. Specifically, with respect to malaria, mor-

from Table 3 for populations at risk of water

tality estimates for each of the four IPCC sce-

stress and Table 6 for ecological indicators,

narios are derived by assuming that (1) in the

indicate that the effect of non-climate-

absence of climate change, population at risk

change-related factors generally outweighs

scales linearly with the global population in

the effect of climate change with respect to

2085 under each scenario, and (2) the ratio of

either human or environmental well-being.

the additional population at risk due to cli-

Climate change is therefore unlikely to be the

mate change to the population at risk absent

most important environmental problem

climate change varies with the square of the

ratio of the global temperature change.61

confronting human or environmental well-

being, at least through the foreseeable future.

Note that the methodology used to trans-

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