This paper provides a general overview of the scientific evidence supporting global warming. The paper is primarily factual in nature, although it clearly supports the idea that global warming is real, and states that drastic steps must be taken to prevent the phenomenon of human-generated climate change from escalating. It provides policy prescriptions in its conclusion.
Global warming is one of the most contentious political issues of our times. It was famously dramatized in Al Gore's An Inconvenient Truth, and remains a hot-button topic of debate. The majority of unbiased, legitimate scientific research supports the existence of human-generated global warming, although the question of what to do to slow the rate of escalating temperatures remains far from settled in the arena of politics. According to one recent review of major scientific publications, 97-98% of "the climate researchers most actively publishing in the field & #8230; supported the basic tenets of ACC (manmade global warming) established by the Intergovernmental Panel on Climate Change" (Blakemore 2012).
The earth's climate and temperature has always been unstable, and there have been periods when overall temperatures have increased or decreased in the earth's history, before modern industrialization. But climate changes after the Industrial Revolution, particularly those since the 1980s, have been particularly rapid -- and troubling. The evidence suggests they are not 'natural' in origin. "Even though the 2000s witnessed a solar output decline resulting in an unusually deep solar minimum in 2007-2009, surface temperatures continue to increase" ("Climate change: Evidence," NASA, 2012). Right now, we should be in a cooling period, according to solar patterns, but because of the "heat-trapping nature of carbon dioxide and other gases" the earth's temperatures have risen ("Climate change: Evidence," NASA, 2012).
Since the 19th century, the thermogenic or heat-trapping properties of carbon dioxide have been known and the earth has grown warmer since 1880. "Most of this warming has occurred since the 1970s, with the 20 warmest years having occurred since 1981 and with all 10 of the warmest years occurring in the past 12 years" ("Climate change: Evidence," NASA, 2012).There is a clear correlation: the greater the rate of industrialization and the more widespread industrialization occurs across the globe, the swifter the rate of warming. Also, in contrast to past epochs, the changes in the earth's climatic patterns have happened "very quickly, geologically-speaking: in tens of years, not in millions or even thousands" ("Climate change: Evidence," NASA, 2012). With the increased rate of melting of the polar ice caps, "global sea level rose about 17 centimeters (6.7 inches) in the last century. The rate in the last decade, however, is nearly double that of the last century" ("Climate change: Evidence," NASA, 2012). The oceans have also grown warmer, with "the top 700 meters (about 2,300 feet) of ocean showing warming of 0.302 degrees Fahrenheit since 1969" ("Climate change: Evidence," NASA, 2012). Shrinking ice sheets and ice mass have also contributed to the increased acidification of the ocean.
The pace of global warming seems destined to continue, unless all nations begin to modify their behaviors. Yet the rapidly-developing world, particularly India and China, seem to be showing a tendency to adopt more Western behaviors, further placing pressures upon the U.S. "There are several greenhouse gases responsible for warming, and humans emit them in a variety of ways. Most come from the combustion of fossil fuels in cars, factories and electricity production" ("Global warming causes," National Geographic, 2012).The heat-trapping gas CO2 has increased in its concentration in the atmosphere. Methane, produced by domestic livestock manure and "ruminant digestion" is "on a molecule-for-molecule basis...a far more active greenhouse gas than carbon dioxide and the second- highest contributor to global warming (Le Blond 2012; "Causes," NASA, 2012). N2O, "the third highest contributor of climate change" is an essential element in food production and is produced by the fertilizers "used to grow crops in the agricultural industry" as well as "gases used for refrigeration and industrial processes" (LeBlond 2012; Global warming causes," National Geographic, 2012).
To reduce the concentration of these gases in the atmosphere requires radical modifications in the way human beings live today. "A proposed reduction in the world's carbon emissions set by the Intergovernmental Panel on Climate Change (IPCC) can only be met if the developed world cuts down meat consumption by 50% per person" and "cuts emissions by an equal amount by 2050" (LeBlond 2012). According to Dr. James Hansen, one of the first NASA scientists to publicize the evidence of global warming: 'if we wanted to restore the energy balance this century, we would need to reduce emissions by six per cent a year, starting this year [2012]. If you wait another 10 years you would have to reduce emissions by 15% a year. That would be almost impossible" (Gray 2012).
There have been some positive developments on the political level as well as in terms of personal consumption to fight global warming. "Since the U.S. government imposed its first minimum mileage standards in 1974, they have been progressively strengthened. Last year, the Obama Administration and automakers agreed to gradually increase the average mileage of U.S. cars to 54 miles per gallon, starting with an average 35 miles per gallon by 2016" ("Global warming: It's real," Patriot-News Editorial Board, 2012). Some recent consumer trends have shown a shift in favor of the public's commitment to environmentally-friendly policies. Switching to electric or hybrid driving vehicles has grown in popularity, particularly given the increased price of gas. The success of the Toyota Prius was unexpected but now almost all of the major car manufacturers today have a hybrid fleet. Even GM, once the purveyor of gas-guzzling cars has produced the Chevy Volt ("2012 Chevy Volt," GM, 2012). Electric cars "charged from the electricity grid produce lower global warming emissions than the average compact gasoline-powered vehicle (with a fuel economy of 27 miles per gallon) -- even when the electricity is produced primarily from coal in regions with the 'dirtiest' electricity grids" ("State of change," Union of Concerned Scientists, 2012). With clean electric grids dominated by wind and solar energy, the impact is nearly zero from electric cars.
Reducing meat consumption, however, has been a harder 'sell,' particularly in the developing world, where increased prosperity inevitably leads to increased meat consumption (Goldenberg 2012). "Some scientists are at work growing artificial meat which would avoid the fertilizers and manure responsible for climate change" (Goldenberg 2012). Fish and chicken leave a smaller carbon footprint than cattle, since cows and other ruminant livestock require extensive grazing land and deforestation. Simply not eating animal products at all (vegetarianism and veganism) is another option embraced by some environmentalists (Goldenberg 2012).
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