Global Warming and Climate Change
Global Warming and Climate Change Date: 2020 From: Gale Opposing Viewpoints Online Collection Publisher: Gale, a Cengage Company Document Type: Topic overview Length: 3,268 words Content Level: (Level 5) Lexile Measure: 1400L Full Text: Though the terms global warming and climate change are often used interchangeably, they have different meanings. Climate change describes long-term shifts in the earth’s weather patterns that affect such factors as temperature, humidity, wind, cloud cover, and precipitation levels. Global warming specifically refers to an increase in the Earth’s average surface temperatures caused by human activities, primarily the burning of fossil fuels. Overwhelming scientific evidence supports the reality of both global warming and climate change, but a vocal minority disagree with the consensus conclusion that these trends are being driven by human activity. The widely accepted scientific model posits that global warming and climate change are being caused and accelerated by the continued use of carbon-rich fossil fuels, as carbon is one of the gasses that traps heat in the earth’s atmosphere. Opponents of this theory believe that current changes in climate and weather patterns are the result of natural cycles that have repeated again and again over the course of Earth’s history. Global warming and climate change are contentious issues with many political implications in the United States. Concerns about the phenomena have inspired activism, laws, and international treaties while also sparking heated debate. The debate over climate change has an influential effect on social and economic policy. Voters have demonstrated a growing willingness to cast ballots in favor of political candidates who share their views. Main Ideas There is strong scientific evidence for global warming and climate change, but some people disagree the trends are anthropogenic, or driven by human activity. The Earth’s atmosphere contains several gases that trap heat from the sun in a phenomenon called the greenhouse effect. These gases are commonly called greenhouse gases and include carbon dioxide, methane, and nitrous oxide. The Intergovernmental Panel on Climate Change (IPCC) estimated in 1990 that sea levels would rise at a rate of 1.9 millimeters per year, but data from NASA shows the actual rate between 1993 and 2019 was much higher at 3.3 millimeters per year. Massive wildfires devastated areas of California in 2018 and 2019. Global warming intensifies the ferocity and frequency of wildfires due to the increased abundance of extremely dry vegetation and high temperatures. The hurricane season of 2017 brought severe weather and sea surges that killed many people and caused more than $215 billion of property damage in Florida, Texas, and Puerto Rico, as well as in several other southern states and countries near the Caribbean Sea. In June 2017 US president Donald Trump announced the United States would withdraw from the Paris Agreement, a 2015 global treaty aimed at limiting the rise in global temperatures that had been championed by his predecessor. Causes of Climate Change Earth’s atmosphere contains several gases that trap heat from the sun and prevent it from escaping into space. This phenomenon is known as the greenhouse effect, and the gases are referred to as greenhouse gases. The main greenhouse gases that occur in nature are carbon dioxide, methane, and nitrous oxide. Without the greenhouse effect, Earth would be too cold to support life. Over time, the amount of greenhouse gases trapped in Earth’s atmosphere has increased significantly, causing worldwide temperatures to rise. Natural processes on Earth constantly create and destroy greenhouse gases. For example, the decay of plant and animal matter produces carbon dioxide, which plants then absorb during photosynthesis. This natural cycle stabilizes atmospheric levels of carbon dioxide. Shifts in the planet’s crust and changes in ocean patterns impact weather, as do fluctuations in the sun’s output of radiation. Volcanic activity also affects the climate because eruptions discharge greenhouse gases and other contaminants into the atmosphere. Climate change scientists at the National Aeronautics and Space Administration (NASA) and other federal and international agencies recognize that these natural factors continue to play a role in climate change, but they generally agree that the impact of these factors alone does not explain the substantial recent rise in Earth’s temperature. Natural causes of climate change are referred to as naturogenic, while causes of climate change related to human activity are called anthropogenic. Earth’s vegetation releases and absorbs more than two hundred billion metric tons of carbon dioxide annually. Human activities, such as the burning of fossil fuels, add approximately seven billion more metric tons per year. Climate scientists believe the cumulative effect of this additional carbon has had a dramatic effect on the atmosphere. In the past 150 years, the concentration of carbon dioxide in the atmosphere has risen by more than 30 percent. Deforestation has also played a role in this increase by eliminating forests that would otherwise have absorbed many tons of carbon dioxide. Increased levels of other greenhouse gases, such as nitrous oxide and methane, have also resulted from human activity. Several agricultural and industrial processes, such as the use of certain fertilizers in farming, produce nitrous oxide on a mass scale. Methane emissions come from the production of fossil fuels as well as landfills and livestock. Even though much smaller quantities of these gases exist in the Earth’s atmosphere, some scientists believe they cause more harm than carbon dioxide, because they appear to have a much greater per-pound effect on the Earth’s temperature. Methane, for example, is about twenty-one times as potent as carbon dioxide at trapping heat. Beginning in October 2015, a methane gas leak from a California storage facility vented about five billion cubic feet of gas into the atmosphere. The leak took more than three months to seal and was finally capped on February 18, 2016. The incident constituted the largest accidental discharge of greenhouse gases in US history, releasing the equivalent of the yearly exhaust emissions from 572,000 automobiles. Humans have also created and released greenhouse gases that do not occur in nature. These include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). These gases, released during such industrial processes as aluminum production and electrical transmission, trap thousands of times more heat in the atmosphere than carbon dioxide. Climate Change Predictions Because climate science measures changes that occur on a regional or global scale over a long period of time, it can be difficult to provide definitive answers to specific questions like “When did climate change begin?” However, since the 1990s, numerous studies have provided evidence of a consensus in the scientific community that anthropogenic climate change is occurring. These studies included surveys as well as analyses of peer-reviewed articles. At least 97 percent of actively publishing climate scientists around the world agree that human activities have contributed to rising global temperatures. Most also agree that the consequences may be devastating, though the exact nature of the changes are difficult to predict. No climate model formulated by scientists to chart climate patterns has had 100 percent accuracy in predicting changes. For instance, most climate models failed to predict a slowdown in rising temperatures starting in 1998 and ending in 2012. Similarly, some predictions have underestimated threats. In its initial assessment of rising sea levels in 1990, the Intergovernmental Panel on Climate Change (IPCC) originally anticipated a sea level rise of 1.9 millimeters per year from that year onward. However, studies by NASA have revealed that sea levels have in fact risen at a rate of 3.3 millimeters per year. Because of the difficulties in creating completely accurate climate change models, skeptics of global warming and climate change note that Earth has experienced cyclical changes in its climate patterns for eons. They also tend to believe that recent climatic shifts are not as severe as indicated and may not necessarily be a direct consequence of human activity. Climate scientists contend that such skepticism may stem from an unwillingness to face the scope of the threat posed to the planet by human activity. Additionally, conservative donors, including several foundations established by wealthy families, have contributed large amounts of money to organizations that promote climate change denial. For instance, the environmental organization Greenpeace claims that foundations linked to the prominent Koch family have donated more than $127 million to such organizations between 1997 and 2017. In 2019 tech giant Google came under fire for making a “substantial” donation to the Competitive Enterprise Institute (CEI), a conservative think tank that helped influence the Trump administration’s 2017 decision to abandon the US commitment to the 2015 Paris Agreement on climate change. However, acknowledgment of the effects of human activities on global warming and climate change has grown steadily in the twentyfirst century. According to a 2019 The Washington Post/Kaiser Family Foundation poll, the majority of Americans accept that anthropogenic climate change is happening. In addition, about half of Americans believe the United States is not doing enough to prevent it and want immediate action on the issue. According to annual polls conducted by Gallup since 2001, the public’s beliefs about global warming had shifted considerably by 2019. About 66 percent believed that global warming is caused by human activity (up from 57 percent in 2001), that climate change has begun to take effect (up from 54 to 59 percent), and that global warming will soon pose a serious threat (up from 35 to 45 percent). Researchers have observed a strong correlation between people’s political affiliations and their levels of concern regarding global warming and acceptance of climate science. In 2019 Pew Research Center reported that 84 percent of Democrats and Democratleaning independents believe climate change is a major threat to the United States, compared to just 27 percent of Republicans and Republican-leaning independents. Numerous Pew studies have yielded similar partisan trends on climate changerelated issues, while Gallup polling has also found that people aged eighteen to thirty-five are more likely than older respondents to believe that the media underestimates the threat of climate change. Effects of Global Warming
