CATO


HANDBOOK


FOR


CONGRESS


POLICY RECOMMENDATIONS FOR THE 108TH CONGRESS 
Washington, D.C. 


45. Global Warming
Congress should vote on the ratification of the Kyoto Protocol on 
global warming, which requires a two-thirds majority in the 
Senate. 
Background 

The United Nations Framework Convention on Climate Change (FCCC) 
and the subsequent Kyoto Protocol require the United States to reduce 
the net emissions of carbon dioxide and other important greenhouse gases 
to 7 percent below 1990 levels, on average, for the five-year period 
beginning in 2008. The Framework Convention and the protocol are based 
on a naive interpretation of a science that now views reductions in carbon 
dioxide as a very inefficient way to influence climate change. As a result, 
the economic costs of the convention and protocol are enormous, and 
the benefits are undetectable. Even if all the world’s nations met their 
commitments under the Kyoto Protocol, there would be no discernible 
effect on the globe’s climate. 

The Framework Convention was signed by the United States at the Rio 
de Janeiro Earth Summit in 1992. As originally conceived, the purpose 
of the convention was ‘‘to prevent dangerous human interference in the 
climate system.’’ The original goal was to reduce emissions of carbon 
dioxide, the principal human ‘‘greenhouse’’ gas, to 1990 levels by the 
year 2000. Only two nations have met that goal, and they have done so 
because of historic changes unrelated to environmental concerns. In 1990 
the reunification of Germany resulted in the absorption of the wildly 
polluting East, whose economic inefficiency was so great that much of 
its industry was simply shut down. Great Britain met the target because 
of privatization of the coal industry. 

Carbon dioxide emissions in the United States have risen approximately 
15 percent since 1990. But at Kyoto in December 1997 the Clinton 


CATO HANDBOOK FOR CONGRESS 

administration, under the leadership of Vice President Al Gore, agreed to 
a protocol to the FCCC that requires us to reduce our emissions 7 percent 
below 1990 levels over the averaging period, 2008–12. Because of recent 
increases in emissions, this constitutes a reduction of between 30 and 40 
percent (depending on whether the increase since 1990 is assumed to be 
exponential or merely linear) beneath where they would be under a ‘‘business 
as usual’’ scenario. That ‘‘business as usual’’ has resulted in one of 
the greatest explosions in wealth creation in the history of the world. 

As shown in the balance of this chapter, while global warming is likely 
to be modest, the Kyoto Protocol will have no detectable effect on that 
warming. These two arguments compelled the Bush administration to 
abandon the protocol. It is now up to the Senate to complete this work 
by voting on ratification, which requires a two-thirds majority. 

The protocol currently enjoys very little support in the Senate, and in 
all likelihood it will fail to achieve the votes necessary for ratification by 
a large margin. There are several reasons for this lack of support: scientific, 
economic, and political. The ultimate elimination of the Kyoto Protocol 
will remove one of the greatest obstacles to technological progress on 
climate change and should result in a rational reexamination of the issue 
and, perhaps, an international agreement more grounded in facts than the 
current protocol. 

Members of Congress should note that calls for dramatic emissions 
reductions are usually accompanied by lurid rhetoric about weather and 
climate disasters. The purpose of this chapter is to provide the facts that 
counter such emotional appeals. 

No credible argument counters the notion that the planetary average 
surface temperature is warmer than it was 100 years ago. But what does 
that warming mean? If that warming were in the coldest air of winter, 
rather than in the heat of summer, the overall effect would clearly change 
from bad to good. Although most mathematical simulations of climate 
predict an overall increase in precipitation, is more precipitation really a 
bad thing? If there were a sudden and dramatic increase in the frequency 
of severe floods with no concomitant positive effects, then obviously the 
answer would be that global warming is a terrible disaster. But what if 
gentle spring rains increase while the severity of hurricanes declines? 

Figure 45.1 details the surface temperature history of the Northern 
Hemisphere, 1900–2001. (Southern Hemisphere records are not as reliable 
because of the paucity of coverage over the vast Southern Ocean and 
Antarctica.) There are two distinct warmings of similar magnitude. The 


Global Warming 
–0.8 
–0.6 
–0.4 
–0.2
0 
0.2 
0.4 
0.6 
0.8
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 
Year 
Temperature Departure (°C) 
Figure 45.1 
Northern Hemisphere annual temperature history, 1900–2001. 
first occurred from 1910 to 1940 and likely had little if anything to do 
with changes in the earth’s greenhouse effect, as three-quarters of the 
greenhouse emissions occurred in the postwar era. Federal scientists Judith 
Lean and David Rind and Harvard astrophysicist Sallie Baliunas argue 
persuasively that this early warming is largely a result of solar changes. 
Warming Occurs Primarily in the Winter, Not the Summer 
The Largest Warming Is in the Coldest, Deadliest Airmasses 
The second warming, which began about 35 years ago, is much more 
interesting. Greenhouse-effect physics predicts that human-induced climate 
change should take place more in the winter than in the summer, and that 
it should further be concentrated in the coldest air of winter. The propensity 
for greenhouse warming to occur in frigid dry air has enormous implications 
that have largely been ignored in the raucous debate about climate 
change. 
In fact, observed warming since World War II is twice as large in 
winter as it is in summer. In the winter, three-quarters of the total warming 
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is confined to the frigid airmasses that reside in Siberia and northwestern 
North America. 

Summer warming has been, predictably, much less than winter warming. 
Less than one-third of the observed warming of the second half of the 20th 
century occurred in the summer, while two-thirds occurred in the winter. 

An individual living in Siberia or northwestern North America has, for 
the last 50 years, experienced a winter half-year warming of nearly 1.1 
degree Celsius. Cold airmasses that originate in these regions, on the 
‘‘edges’’ of winter (April and October), are usually responsible for the 
last freeze in the spring and the first freeze in the fall in temperate latitudes. 
Reducing the inherent coldness lengthens the growing season. There are 
several lines of evidence in the scientific literature indicating that this 
is occurring. 

Temperature Variability Is Declining, Not Increasing 

One of the common arguments for emissions reductions is the notion 
that the weather has become more variable. The opposite is true. 

Economic and ecological systems are adapted to both average conditions 
and expected variation. So, as the temperature warms, do annual and 
seasonal temperature swings become more erratic? In the last century, 
some years were warm and some cold. This natural variability allows us 
to examine whether the seasonal and monthly variability in those years 
is different from the variability in years with near-mean temperatures. 

Figure 45.2 shows monthly variability in the last 100 years. Before 
1940 (including the warming of 1910–40), there was little change. In the 
last third of the 20th century, there was a considerable decline. In other 
words, as the greenhouse enhancement has warmed the extremely cold 
air of Siberia and northwestern North America, the within-year variability 
has dropped. There is no evidence that the fluctuations in the earth’s 
temperatures are greater now than they were at the beginning of the 20th 
century. Conversely, most evidence suggests that temperature has become 
less variable. 

Precipitation, Droughts, and Floods Show No Ominous Changes 

The standard measure of drought is known as the Palmer Drought 
Severity Index. Figure 45.3 shows the percentage of the lower 48 U.S. 
states experiencing severe Palmer drought back to the beginning of the 
record in 1895. Clearly, there is no overall trend; what’s more, the drought 


Global Warming 
0 
0.5
1 
1.5
2 
2.5 
3 
3.5
4
1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 
Year 
Temperature Variability 
Figure 45.2 
Intra-annual global temperature variability. Temperature variability has been declining 
since greenhouse warming began. 
0 
10 
20 
30 
40 
50 
60 
70
1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 
Year 
Percent of Country 
Figure 45.3 
The percentage of the United States experiencing severe or extreme drought 
conditions fluctuates from year to year but shows no long-term trend. 
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periods in the 1930s and 1950s dwarf anything we saw in the last quarter 
of the 20th century. 
What about rainfall? The Palmer Index measures wetness as well as 
drought. Here we do see a slight but statistically significant increase. This 
is clearly a net benefit of climate change. Every summer most of the 
United States experiences a moisture deficit, as solar-driven evaporation 
dries the soil at a greater rate than rainfall can replenish moisture. So any 
increase in precipitation is likely to be welcomed by American agriculture. 
Figure 45.4 demonstrates this increase. 
Even this salutary trend has been twisted in the service of climate 
doomsaying. In August 2002, Maryland governor Parris Glendening 
blamed the region’s severe drought on global warming. In fact, U.S. 
precipitation has increased by about 10 percent in the last 100 years, or 
roughly three inches. Some scientists attribute that to other atmospheric 
changes accompanying warming. For warming to have increased the frequency 
of drought, then, this additional increment of rainfall, plus another 
large amount sufficient to provoke a major drought, must somehow be 
evaporated away by higher temperatures. This is simply not the case: The 
average change in U.S. temperature in the last 100 years has been a mere 
0 
10 
20 
30 
40 
50 
60 
70 
80 
1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 
Year 
Percent of Country 
Figure 45.4 
The percentage of the United States that is substantially wet shows a statistically 
significant increase. This is largely beneficial for American agriculture. 
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Global Warming 

0.4°C, which increases evaporation a mere half-inch or so. So, if anything, 
global warming has added about 2.5 inches of water per year to U.S. soil. 

We often hear that flooding rains are increasing from global warming. 
This originates from a study of U.S. rainfall by federal climatologist Tom 
Karl, who found that there is an increasing fraction of U.S. rainfall coming 
from storms of more than two inches per day. 

The environmental lobby has seized upon this fact without actual analysis 
of the results. What Karl found is that the majority of the increase is 
in storms of between two and three inches per day. Those are not floods. 
With regard to storms capable of significant flooding, those producing 
five or more inches of rainfall a day, the increase is so slight as to be 
meaningless. On the average, a person will now experience two more 
days in his entire expected life span of 27,350 days in which it rains five 
or more inches. 

Another way to look for precipitation extremes is to examine streamflow 
data in undammed basins. In 1999 U.S. Geological Survey scientist Harry 
Lins published a paper showing no increase in the frequency of flooding 
streamflow but a decrease in the frequency of the lowest (drought) flow 
categories. That is to say, streamflow records indicate decreased drought 
and no change in floods over the long historical perspective. 

There Is No Increase in the Frequency or Severity of Hurricanes 

The notion that global warming is making the most destructive storms 
worse or more frequent is one of the most compelling appeals for greenhouse 
emission reductions. It has absolutely no basis in fact. 

Figure 45.5 shows the number of hurricanes striking the United States 
per decade. It is obvious that, if anything, recent decades are notable for 
their lack of storms. Of even more interest is the fact that the maximum 
wind velocity measured in Atlantic and Caribbean Basin storms has actually 
declined significantly in the last 50 years, as shown in data published 
by the United Nations Intergovernmental Panel on Climate Change (IPCC) 
(Figure 45.6). 

Heat-Related Mortality Is Declining, Not Increasing 

The popular perception is that heat-related deaths have increased, and 
will continue to increase, with global warming. The IPCC says, ‘‘[Based 
upon data from several North American cities], the annual number of 
heat-related deaths would approximately double by 2020 and would 
increase several fold by 2050.’’ 

Research shows that this is just plain wrong. Figure 45.7 shows the 
relation of death rates in Philadelphia, a typical urban core, to ‘‘effective 


CATO HANDBOOK FOR CONGRESS

Maximum Wind Speed

(m/s)

Number

25 

20 

15 

10 

5 

0 
1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 


Decade 

Figure 45.5 

Number of hurricanes striking the United States per decade. If anything, recent 
decades have had fewer storms than average. 

55 

50 

45 

40 

35 


30 
1940 1950 1960 1970 1980 1990 2000 


Year 

Figure 45.6 

Maximum winds measured by aircraft in Atlantic and Caribbean storms show a 

statistically significant decline (IPCC 1996), despite stories of increased severity. 


Global Warming 


Figure 45.7 

In Philadelphia, typical of most American cities, the daily mortality generally 
decreases with temperature, with the exception of the very hottest days. 

temperature,’’ which is the combination of heat and humidity that makes 
people uncomfortable. In general, heat-related deaths decline with effective 
temperature, although there are a few days that show remarkable death 
excursions at high temperature—the few dots that can be seen in the upper 
right portion of the graph. These are death excursions similar to those of 
Chicago’s July 1995 heat wave, which was responsible for several hundred 
excess deaths. 

But, as Figure 45.8 shows, as we progressed through the last half of 
the 20th century, the increase in the number of people who died at high 
temperatures declined to near-zero values. This is a result of increased 
use of air conditioning, effective medical care, and public education about 
the dangers of excessive heat. In other words, over time, the same technology 
that slightly raises the surface temperature (fossil-fuel-driven electricity 
production) saves lives. Proposals to make energy more expensive as a 
means of fighting climate change will have the perverse effect of killing 
those who can least afford expensive electricity, resulting in a return to 
the heat-related death patterns of the past. 

Future Warming Is Likely to Be Modest in Scale 

By now, dozens of different computer simulations that estimate future 
warming have been executed. How do we decide which, if any, is likely 
to be correct? 


CATO HANDBOOK FOR CONGRESS 
10 
15 
20 
25 
30 
35 
40 
45 
50Average Daily Mortality1964–1966 1973–1979 
1980–1989 1990–1998 
10 20 40 60 80 100120 

4 p.m. Apparent Temperature (°F) 

Figure 45.8 

In a northern city, such as Philadelphia, where extremely hot conditions occur less 
frequently than in the South, the population exhibits a higher mortality rate on hot 
days. However, over time, the sensitivity of the population of Philadelphia to high 
temperatures has been declining. 

The key to the future lies in the rather extended period during which 
humans have already altered the natural greenhouse effect—roughly from 
the start of the Industrial Revolution in the late 19th century to the present. 
The concentration of atmospheric carbon dioxide—the main greenhouse 
emission resulting from human activity—varied from 260 to 320 parts 
per million (ppm) between the end of the glacial stage, 10,800 years ago, 
and the Industrial Revolution. The average value during that period was 
near the low end of that range, about 280 ppm. The current concentration 
is 365 ppm, about a 30 percent increase. 

But there are other emissions that increase the atmosphere’s natural 
greenhouse effect. Methane emissions, for example, contribute a warming 
of another 20 percent beyond the enhanced carbon dioxide greenhouse 
effect. Another 15 percent increase comes from chlorofluorocarbons 
(CFCs), refrigerants whose atmospheric concentrations have yet to decline 
much, despite the Montreal Protocol against their manufacture because 
they might reduce stratospheric ozone. A host of other anthropogenic 
emissions contributes much smaller additional increments. When all is 


Global Warming 
said and done, in toto the emissions produce a ‘‘carbon dioxide equivalent’’ 
concentration that is about 60 percent above the background levels recorded 
prior to the Industrial Revolution. 
Nearly 20 years ago, a few climate scientists noted that the planet had 
notwarmed as much as would be expected fromearly computer simulations 
of greenhouse warming. By 1996 the IPCC acknowledged that that observation 
had become the consensus of the broad scientific constituency. 
Although it has been fashionable to try to ‘‘explain’’ the lack of warming 
by the presence of sulfate aerosols, a product of combustion that was 
thought to cool the surface, that explanation has never withstood simple 
tests. The alternative explanation put forth by the IPCCis that the sensitivity 
of surface temperature was simply overestimated. 
Evidence leads us to conclude that the warming we saw in the last 
third of the 20th century was largely from greenhouse changes. It is very 
linear (constant in rate) at about 0.15°C per decade at the surface. A small 
solar component is calculated to be around 0.02°C per decade. That leaves 
us with about 0.13°C per decade as a human greenhouse signal. 
Figure 45.9 shows the warming since 1960 as well as output from a 
large suite of climate forecast models. The models’ forecasts are also all 
–1 
–0.5
0 
0.5
1 
1.5
2 
2.5
3 
3.5 
NCAR CSM, 1%/year 
NCAR CSM, Adjusted 
HadCM2.1%/year 
HadCM2.Adjusted 
Hansen, Scenario B 
GFDL, 1%/year 
GFDL, Adjusted 
Observations 
1960 1980 2000 2020 2040 2060 2080 2100 
Year 
Temperature Change (°C) 
Figure 45.9 
Observed warming of the last 35 years superimposed on typical climate model 
projections. The observed linear trend is near the lowest value that the climate models 
predict and considerably below the mean projected warming. 
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linear, but note that they differ in the slope of their projected warming. 
These differences result from internal model dynamics and assumptions, 
including the rate of increase of greenhouse changes. For example, the 
rate of greenhouse increase has been running at about 75 percent of the 
UN’s ‘‘central’’ estimate for decades. Most computer models assume an 
even larger value than the UN’s already high figure; indeed, several 
researchers have recently demonstrated that the true value is a mere 45 
percent of the modeled assumption. 

Nonetheless, with few exceptions, all the climate models predict warmings 
over the next century that are essentially linear. It seems logical to 
now let nature adjudicate what the proper rate for warming is; this is also 
shown in Figure 45.9. By the middle of this century, we are left with an 
additional surface warming of 0.65°C to 0.75°C, with 0.75°C to 0.85°C 
in the winter half year and 0.60°C to 0.65°C in the summer. 

Interestingly, these 50-year figures are quite similar to the warming that 
occurred during the late 20th century. 

What have we to show for a century of warming? In 1900 life expectancy 
at birth in the United States was 42 years. After 100 years of global 
warming, it was exactly twice that number, 84 years. Urban infrastructure 
in the United States has adapted so well to both average and warmed 
climates that heat-related deaths are disappearing. After a global warming 
of 0.6°C, U.S. crop yields quintupled. World food production per capita 
has increased by nearly 50 percent in the last half century. An untold 
story is that carbon dioxide itself makes most crops grow better: by the year 
2050 that direct stimulation of planetary greening will feed an increment of 

1.5 billion people the equivalent of today’s diet. 
The Kyoto Protocol Does Nothing about Global Warming 

No known mechanism can stop global warming in the near term. International 
agreements, such as the Kyoto Protocol to the United Nations Framework 
Convention on Climate Change, will have no detectable effect on 
average temperature within any reasonable policy time frame of 50 years 
or so—even with full compliance. Climate modelers at the U.S. National 
Center for Atmospheric Research calculate that full compliance with the 
Kyoto Protocol by all signatory nations would reduce global surface temperature 
by 0.07°C by 2050, and 0.14°C by 2100. Congress should note the 
dangers of an expensive environmental accord with no benefit. The Senate 
should consider the Kyoto Protocol for ratification, with the resultant 
negative vote paving the way for more rational environmental regulation. 


Global Warming 

Recently, National Aeronautics and Space Administration scientist 
James Hansen, whose 1988 congressional testimony started the global 
warming furor, wrote that reducing carbon dioxide is a highly ineffective 
means of slowing global warming in the 50-year time horizon. Rather, 
he argues, concentrating on the other greenhouse gases, such as CFCs 
and methane (which has stopped increasing in the atmosphere for only 
partially known reasons), is much more effective and politically acceptable 
than the costly Kyoto Protocol, which, he wrote, ‘‘cast the developed and 
developing worlds as adversaries.’’ Hansen is clearly stating that the Kyoto 
Protocol is scientifically ill-advised. 

Rather, the more serious question the facts on global warming provoke 
is this: Is the way the planet warms something that we should even try 
to stop? 

Suggested Readings 

Balling, R. C. Jr., P. J. Michaels, and P. C. Knappenberger. ‘‘Analysis of Winter and 
Summer Warming Rates in Gridded Temperature Time Series.’’ Climate Research 
9 (1988): 175–81. 

Davis, R. E., et al. ‘‘Decadal Changes in Summer Mortality in the United States.’’ 
Proceedings of the 12th Conference on Applied Climatology, Asheville, N.C., 2000, 
pp. 184–87. 

Hansen, J. E., et al. ‘‘A Common-Sense Climate Index: Is Our Climate Changing 
Noticeably?’’ Proceedings of the National Academy of Sciences 95 (2000): 4113–20. 
. ‘‘Global Warming in the Twenty-First Century: An Alternative Scenario.’’ 

Proceedings of the National Academy of Sciences (2000), www.pnas.org. 

Intergovernmental Panel on Climate Change. Climate Change 1995: The Science of 
Climate Change: Contribution of Working Group I to the Second Assessment Report 
of the Intergovernmental Panel on Climate Change. Edited by J. T. Houghton et al. 
Cambridge: Cambridge University Press, 1996. 

Karl, T. R., R. W. Knight, and N. Plummer. ‘‘Trends in High-Frequency Climate 
Variability in the Twentieth Century.’’ Nature 377 (1995): 217–20. 
Lean, J., and D. Rind. ‘‘Climate Forcing by Changing Solar Radiation.’’ Journal of 
Climate 11 (1998): 3069–94. 
Lins, H. F., and J. R. Slack. ‘‘Streamflow Trends in the United States.’’ Geophysical 
Research Letters 26 (1999): 277–330. 
Michaels, P. J. ‘‘The Consequences of Kyoto.’’ Cato Institute Policy Analysis no. 307, 
May 7, 1998. 
. ‘‘Long Hot Year: Latest Science Debunks Global Warming Hysteria.’’ Cato 

Institute Policy Analysis no. 329, December 31, 1998. 
Michaels, P. J., and R. C. Balling Jr. The Satanic Gases. Washington: Cato Institute, 2000. 
Michaels, P. J., et al. ‘‘Analysis of Trends in the Variability of Daily and Monthly 

Historical Temperature Measurements.’’ Climate Research 10 (1998): 27–33. 
. ‘‘Observed Warming in Cold Anticyclones.’’ Climate Research 14 (2000): 1–6. 
Wittwer, S. H. Food, Climate, and Carbon Dioxide. Boca Raton, Fla.: CRC Press, 1995. 

—Prepared by Patrick J. Michaels