Human activities are causing an enormous, dangerous experiment to be conducted around the globe—in fact, to the globe. In the atmosphere, various gases, including water vapor, carbon dioxide and other trace chemicals, act like the glass of a greenhouse and trap heat near the earth’s surface. This natural "greenhouse effect" is essential for life on the planet, keeping global average surface temperatures warmer than they otherwise would be. But human activities are changing and enhancing this natural effect – thickening the walls of the "greenhouse" – with significant consequences for the global climate. The burning of fossil fuels, deforestation, and certain agricultural activities and industrial practices unleash billions of tons of carbon dioxide (CO2) into the environment. Since the industrial revolution, atmospheric levels of carbon dioxide have increased by more than 30 percent to levels unsurpassed in the past 160,000 years.
The increase in the earth’s average temperature is often referred to as "global warming." But since higher temperatures may not be the only effect of increased pollutants in the atmosphere, many scientists and environmentalists now prefer to use the broader term "climate change." Scientists have discovered that in some places, climate change may cause temperatures to decrease, even if the earth’s average temperature rises, and the term global warming does not imply the other atmospheric changes, such as severe weather patterns, that are predicted to occur.
At the behest of the Reagan and first Bush Administrations, a massive international scientific effort known as the Intergovernmental Panel on Climate Change (IPCC) was launched to explore the scientific and policy issues associated with the climate challenge. The IPCC assembled 2,500 climate change experts and conducted one of the most thorough, comprehensive and peer-reviewed scientific inquiries in human history. In the IPCC’s 1990 First Assessment Report, scientists predicted an increase of two to six degrees Fahrenheit over the next century, and called on industrialized nations to cut global warming pollution by 60 to 80 percent. This report was used as background for the Framework Convention on Climate Change, which was signed by President George H.W. Bush in 1992 and ratified by the Senate that same year. The treaty suggested that industrialized countries voluntarily cut carbon dioxide emissions, but imposed no binding requirements on the signatories. The IPCC’s Second Assessment Report, issued in 1995, concluded that "the balance of evidence suggests that there is a discernable human influence on global climate."
The Third Assessment Report, released in 2001, predicts an increase in the earth’s average temperature of as much as 10.4 degrees by 2100, more than 60 percent higher than what the IPCC predicted in its last study. An increase of this magnitude would be the most rapid change in 10,000 years. The report, approved unanimously, is the most comprehensive study on global warming to date.
The science is clear: unless we change our ways and stop polluting the atmosphere, the world’s climate will change even more dramatically; further increasing temperatures, raising sea levels, flooding coastal areas, threatening forests and agriculture, and spreading harmful diseases.
Over the next 100 years, the IPCC predicts that increasing temperatures could raise sea levels by as much as 34 inches, causing floods that could displace tens of millions of people in low-lying areas such as China’s Pearl River Delta, much of Bangladesh, densely populated areas of Egypt, and in small island nations such as the Marshall Islands. Malaria, dengue fever, and other infectious diseases could spread to areas that have never experienced them before due to increased flying ranges for mosquitoes. Droughts could strike farmlands, exacerbating world hunger.
While the world’s wealthiest nations are most responsible for climate change, communities and nations that are poor, agriculturally marginal, and lacking adequate health infrastructures will be most severely impacted. Farmers are most vulnerable to changing rainfall patterns that may make their land infertile. Slum-dwellers in coastal areas or in floodplains are least able to relocate to avoid chronic flooding. Undeveloped areas are least able to prevent the spread of infectious disease.
The United States will be better able to counteract the negative effects of climate change than developing nations, but it will not be immune from those effects. In America, places like South Florida, coastal Massachusetts and California, Southern Louisiana and other Gulf Coast areas and Manhattan Island are likely to experience severe flooding as a result of sea level rises associated with climate change. An Environmental Defense Fund report suggests that by the end of this century, large portions of New York City and surrounding areas could experience "temporary flooding or permanent inundation."
The Third Assessment Report cited "new and stronger evidence that most of the observed warming of the last 50 years is attributable to human activities," primarily the burning of oil, gasoline, and coal, which produce carbon dioxide and other gases that trap heat in the earth’s atmosphere. Carbon dioxide levels have increased by 31 percent over the past 250 years, reaching a concentration unseen on the planet in 420,000 years and perhaps as far back as 20 million years.
We in America use twice as much energy to produce a unit of gross domestic product as our primary industrial competitors, Germany and Japan. The top five producers of CO2 are the U.S., China, Russia, Japan, and U.S. autos. U.S. cars emit more CO2 than all but four of the world’s countries. However, despite our current consumption habits, there are tremendous economic opportunities available to the United States in leading a broad international effort to meet the climate challenge. In fact, a group of 2,500 economists, including eight Nobel Prize winners, issued a statement in 1997 rejecting the idea that addressing climate change requires trading off our economic well-being and asserting that the United States could, in fact, prevent further environmental damage and increase economic efficiency by converting to alternative modes of energy production and consumption.