SUMMARY
INTRODUCTION

ENERGY MYTHS

ENVIRONMENTAL MYTHS

OPEN QUESTIONS AND OVERLOOKED REALITIES

POLICY IMPLICATIONS
APPENDIX


 

 

 

 

ENVIRONMENTAL MYTHS

MYTH 9: GLOBAL WARMING HAS ACCELERATED IN THE PAST FIFTY YEARS

Since the beginning of the Industrial Revolution in the mid-eighteenth century, human activities have added a considerably larger share of heat-trapping greenhouse gases to the atmosphere than during any previous era.[18] For that reason, discussion of global warming has emphasized the role that these activities—notably, coal combustion for electricity generation and oil combustion for transportation—may play in climate change. It is not surprising, then, that more than three-quarters of respondents believe that the planet warmed more during the latter half of the twentieth century, when global energy consumption was greater and fossil-fuel combustion was much higher.

Nevertheless, scientists generally believe that the earth warmed at least as much, if not more, from 1900 to 1950 than during the subsequent fifty years. Indeed, the global climate pattern saw a relatively pronounced rise in temperatures from shortly after the turn of the century to about 1945. Then temperatures cooled somewhat until 1976, when they began to rise again with slightly more acceleration.[19]

To what degree are human-induced greenhouse gases responsible for warming the atmosphere? The answer is unclear. Despite the certitude with which the media and politicians treat the issue, the science remains muddled. Temperatures fluctuate: they go up in some regions, down in others, and may be affected by naturally occurring phenomena, such as El Niño.

There are some—most notably, former vice president Al Gore—who argue that the climate fluctuations of the twentieth century are due to greenhouse gas emissions, particularly carbon dioxide generated by burning fossil fuels. But other observers are not so sure. According to the George C. Marshall Institute, “Much of the observed temperature rise of 0.5°C [approximately 1°F] occurred before 1940, whereas most of the additional carbon dioxide (over 80 percent) entered the atmosphere after 1940.… The increase in greenhouse gases cannot explain the rapid rise in temperature prior to 1940, and it cannot explain the drop in temperature from 1940 to 1970.… Natural factors must have caused most of that [early-twentieth-century] warming.”[20]

In their book Energy: The Master Resource, Robert L. Bradley, Jr. and Richard W. Fulmer raise an interesting point about the supposed impact of carbon dioxide as the principal agent of climate change: “The most common greenhouse gas is water vapor, which accounts for about 94 percent of the natural greenhouse effect. Its atmospheric concentration is ten times that of CO2. Water vapor’s impact on the climate is complex and not well understood. It can both warm and cool the atmosphere.”[21]

The lack of certainty that surrounds the climate-change debate was underscored in December 2006, when Britain’s Sunday Telegraph reported that the United Nations Intergovernmental Panel on Climate Change (IPCC) was preparing to reduce its overall estimate of mankind’s impact on climate change by as much as 25 percent. The story also noted that the IPCC had already “been forced to halve its predictions for sea-level rise by 2100, one of the key threats from climate change.”[22]

 

ENERGY AND THE ENVIRONMENT: MYTHS AND FACTS

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Clarice Smith
Deputy Director,
Communications
Manhattan Institute
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Copyright The Manhattan Institute 2007