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 Environmental Education and Advocacy
Global Warming - Background
What is global warming? Since pre-industrial times, the atmospheric concentration of carbon dioxide has increased by 31 percent. Over the same period, atmospheric methane, another global warming gas, has risen by 151 percent, mostly from agricultural activities like growing rice and raising cattle. As the concentration of these gases grows, more heat is trapped by the atmosphere and less escapes back into space. The increase in trapped heat changes the climate, causing altered weather patterns that can bring unusually intense precipitation or dry spells and more severe storms. Though Americans make up just 4 percent of the world's population, we produce 25 percent of the carbon dioxide pollution from fossil-fuel burning—by far the largest share of any country. Coal-burning power plants are the largest U.S. source of carbon dioxide pollution—they produce 2.5 billion tons every year. Automobiles, the second largest source, create nearly 1.5 billion tons of carbon dioxide annually. SOURCES: Union of Concerned Scientists "Authoritative Report Confirms Human Activity Driving Global Warming" (2007); Pew Center on Global Climate Change, "Climate Change 101" (www.pewclimate.org); Union of Concerned Scientists, "Frequently Asked Questions About Global Warming" (www.ucsusa.org). Hasn’t the earth’s climate changed before?Although local temperatures fluctuate naturally, over the past 50 years the average global temperature has increased at the fastest rate in recorded history, and scientists confirm that this is due not to natural causes, but rather to human activity. And experts think the trend is accelerating: eleven of the last twelve years rank among the hottest years on record. Global average temperatures have risen over the twentieth century, and when scientists have attempted to reproduce these twentieth-century trends in their climate models, they are only able to do so when they include emissions from human use of fossil fuels in their models in addition to natural fluctuations in temperature. And scientists say that unless we curb global warming emissions, average U.S. temperatures could rise 10 degrees by the end of the century. SOURCES: Union of Concerned Scientists, "Authoritative Report Confirms Human Activity Driving Global Warming," "Global Warming 101: 2005 Tied 1998 As World's Hottest Year," and "Frequently Asked Questions About Global Warming" (www.ucsusa.org); Pew Center on Global Climate Change, "Climate Change 101" (www.pewclimate.org). What are the impacts of global warming now and in the future?Global warming is already causing damage in many parts of the globe. In 2003, extreme heat waves caused more than 20,000 deaths in Europe. In many parts of the western United States, severe drought has led to increases in wildfires and drops in water reserves. The 2007 IPCC report confirms that the intensity and extent of droughts have increased in the past four decades "particularly in the tropics and subtropics." Droughts have been linked to changes in sea surface temperatures, wind patterns, and decreased snowpack and snow cover. The IPCC report also confirms that the Arctic ice area has shrunk by about 2.7 percent per decade since 1978 and that "average Arctic temperatures increased at almost twice the global average rate over the past 100 years. "If nothing is done to halt this warming trend, we will see even more serious impacts around the globe, including severe drought in many areas with accompanying disruptions in food and water supplies, rising sea levels and coastal flooding, warmer sea temperatures leading to more intense hurricanes and typhoons around the globe, the unchecked spread of pests and diseases, and the extinction of many plant and animal species. The Intergovernmental Panel on Climate Change (IPCC) is a
group of leading scientists from around the globe who have been
studying data on climate for decades. Early in 2007, the IPCC began
releasing a series of reports that reflect the current state of
scientific knowledge about the causes of climate change, the impacts
it is already having in communities around the world, and what we
can expect to occur if steps are not taken to reduce emissions of
carbon dioxide and other gases that are causing the earth's climate
to grow warmer. SOURCES: Environmental Defense, "Global Warming Myths and Facts" (www.fightglobalwarming.com), and "The Latest Myths and Facts on Global Warming" (2005); Union of Concerned Scientists, "Authoritative Report Confirms Human Activity Driving Global Warming" (www.ucsusa.org); IPCC, "Climate Change 2007: The Physical Science Basis, Summary for Policymakers" (February 2007) (available for download at http://www.ipcc.ch/); IPCC, "Climate Change 2007: Impacts, Adaptation and Vulnerability, Summary for Policymakers" (April 2007) (available for download at http://www.ipcc.ch/) What Individuals and Congregations Can Do, and What the ELCA is Doing Printer-friendly version of the global warming fact sheet (pdf) February 2007
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