The theory that global warming has anthropogenic causes has existed for over a century, and scientists have collected evidence on global warming for over fifty years. In spite of the evidence, the public generally lives in the dark, constantly wondering if global warming is fact or fiction. Global warming is the increase in the Earth’s temperature caused by increased emission of greenhouse gases into the atmosphere (1). The greenhouse G gases, including CO2, form a blanket in the Earth’s atmosphere that traps heat and causes global temperatures to increase (1).
This theory of global warming was first offered by a Swedish chemist named Svante Arrhenius in 1896 (2). Arrhenius estimated that “doubling the level of carbon dioxide in the atmosphere would raise the mean global temperature by several degrees” (2). Even then, his audience was skeptical as many other factors could also affect global temperature. Since Arrhenius’ paper, the global warming discussion has grown convoluted as both scientists and the media have addressed the subject. Scientists track climate change and publish their evidence, but then the media hypes it up in its articles to the public.
To add to the confusion, the public tends to avoid thinking much about the topic unless extreme weather occurs unexpectedly. However, despite overwhelming opinions, there are facts to support both sides of the debate. Media vs. Science The greatest source of confusion about global warming comes from the media. During periods of natural disaster—earthquakes, floods, hurricanes— the media reports more heavily about the existence of global warming. At other times, and in certain regions, the media stops discussing global warming completely.
When global warming first came to the forefront of science, politics, and our culture, scientists were the main sources of information for the media (3). More recently, the sources have changed to interest groups and politicians rather than those directly researching the topic (3). For example, in 2006, Al Gore created the well-known documentary “An Inconvenient Truth” to relay certain facts and predictions about global warming. His documentary made over $49 million, reaching millions of people and starting more conversations about global warming (4).
Its success outweighs the success of most Image courtesy of Robert Simmon/NASA. During the decade between 2000 and 2009, average surface temperatures increased by as much as two degrees Celsius in certain locations over benchmarks recorded between 1951 and 1980. FALL 2011 15 papers published in scientific magazines because it reached such a vast audience (4). The politician replaced the scientists as the informer of the public. This mixing of sources from scientists and politicians has caused the media to convey a greater sense of uncertainty about global warming.
PhD student Jessica Durfee and associate professor Julia Corbett from the University of Utah department of communication studied the public’s response to articles about global warming that used conflicting sources. Durfee and Corbett made up four versions of a news story based on a scientific article that suggested some uncertainty about global warming. Several people read each version, which differed in the amount of controversy and context they included, and then took a survey about their certainty of global warming. Durfee and Corbett found that scientific context led to the greatest ertainty about global warming, and controversy caused greater uncertainty about the issue. Furthermore, added controversy between the differing scientific and political opinions diminished the perceived importance of global warming. (3) The Internet provides another source of confusion about global warming. Scientific articles, news articles, and blog entries found on the Internet all provide accounts of global warming but have dramatically different levels of credibility. However, the average Internet user does not take the credibility of his or her sources into account.
To further complicate matters, the Internet has so many articles on the subject that the information a reader receives depends on factors such as the Web design of the article and the sites to which the article is linked rather than the credibility and truth of the article. Thus, the Internet does not always provide clear, high-quality facts and evidence for global warming. (1) Scientific Evidence The global warming controversy also exists within the scientific community. Scientists agree that the theory makes sense: increased concentrations of greenhouse gases within the atmosphere should cause temperatures to rise (1).
However, they disagree about whether and 16 how global warming has occurred. Scientists have a wide array of evidence to support the theory that man has caused global warming. Firstly, evidence from meteorological stations that record the global mean temperature supports the claim that global temperature has steadily risen since 1980. Scientists have also studied ice cores to measure the amount of carbon dioxide present in the atmosphere during a given year. By plotting the temperature information with the measurements of carbon dioxide, scientists have found that the two have a positive correlation.
Both temperature and the amount of carbon dioxide in the atmosphere have steadily increased since 1980, causing many scientists to agree that greater carbon dioxide emissions cause the temperature to increase. (5) In 2007, Nature published a recap of changes that had occurred since 2005. Within those two years, the rate of polar ice melting increased, Antarctica weather balloons steadily warmed, and the sea level rose (6). Earth scientists also point to evidence from the natural climate change cycles of the Earth. The Earth has gone through many natural phases of climate change.
Until approximately 2. 75 million years ago, the climate changed every 23,000 years or so (7). After that, the intervals between the climate changes increased to today’s interval of 100,000 years. Again, the science world has reached a consensus that with this evidence, the Earth does appear to be warming. However, the skeptics still assert that man has not acted as the sole or primary factor causing global warming. Skeptical scientists point to evidence to back their claim that man is not the cause of global warming. These skeptics believe that global warming is a purely natural process.
Skeptics discount much of the evidence that pro-global warming scientists have put forth. They claim that some research units that provide the global mean temperature series are “hiding data and falsifying scientific evidence on global warming. ” More substantively, the skeptics also point out that the temperature data does not cover much of the world’s geography, and the temperature data is negatively affected by urban expansion in what is known as the “heat island effect. ” Skeptics also accuse climatologists who predict future global warming of leaving out the impact of natural processes, which are not easy to predict. 8) Another factor that affects both groups’ opinions is the groups’ different sources of funding. The skeptics tend to be backed by industries that work with fossil fuels. Fossil fuel industries do not care so much about the debate as creating confusion amongst the public about the topic of global warming. Thus, while scientists generally agree that the Earth is warming, they disagree about the cause of global warming. More research will be needed to assign a definite cause to global warming. (1) Global Warming as a Boon and a Bane
With all the confusion surrounding the global warming debate, much of the public only takes from the media that global warming will harm our world. However, global warming has potential benefits as well as drawbacks. First of all, as the temperature increases, the Earth will have a longer growing season in many areas. In general, there will be less freezing weather, and the increased temperatures and carbon dioxide levels will allow more plant growth. With more plant growth and a longer growing season, there will be more food for people and livestock.
The warmer weather will also positively affect transportation. Airplanes, trains, buses, and cars will stop having cold weather-related delays for ice and snow. Thus, contrary to popular belief, global warming can have some benefits. (9) Of course, global warming also has many negative effects on the Earth. Global warming is and will continue to have dramatic effects on aquatic life and biodiversity. To compound the natural detrimental effects to ecosystems, humans may further disturb the ecosystems. For example, by trying to combat the effects of rising sea levels, man may work to maintain the coastline.
In our attempts to protect the coastline habitat, other species may disappear. Increased temperatures will also negatively affect the food supply in many places, nullifying the benefits of a longer growing season. The temperature increases will bring hotter temperatures in the sum- DArtmouth unDergrADuAte JournAL oF Science mer, which may cause plants to die. It could also cause weather patterns, such as more intense floods and storms. (9) In the future, global warming could prove to be a boon and a bane to the world, but it is impossible to estimate just how much of either it could be.
Water Vapor as a Greenhouse Gas Carbon dioxide is not the only greenhouse gas contributing to global warming; at high altitudes, water vapor also acts as a greenhouse gas, trapping heat on the Earth’s surface (10). Water vapor acts as positive feedback to the greenhouse gas phenomenon because it prevents heat from leaving the Earth’s atmosphere, just like carbon dioxide. Carbon dioxide causes the greenhouse effect, but water vapor is a more serious problem because as the temperature rises from the greenhouse effect, more water is able to stay in its gaseous form higher in the atmosphere (10).
Scientists have used computer models to find that the water vapor intensifies the warming effects of carbon dioxide by at least a factor of two (11). On the other hand, water vapor also contributes the global cooling process as it condenses and falls as rain when too much of it exists lower in the atmosphere. It also blocks some of the sun’s heat from reaching the Earth (11). Overall, water vapor currently has a net effect of keeping the Earth cooler even though it acts as a greenhouse gas (11). can each decide for ourselves where we stand in the global warming debate. References: 1. P. Moriarty, D.
Kennedy. Cybernet. Syst. 35, 723-725 (2004). 2. S. Weart, B. Atom. Sci. 67, 41-50 (2011). 3. J. Durfee, J. Corbett. Nieman Reports 59, 88-89 (2005). 4. S. Quiring, GeoJournal 70, 1-3 (2007). 5. G. A. Florides, P. Christodoulides. Environ. Int. 35, 390-401 (2009). 6. P. Pockley, Australasian Science 28, 28-31 (2007). 7. J. Rose, P. Geologist. Assoc. 121, 334-341 (2010). 8. S. Wang, Chinese Sci. Bull. 55, 1961-1962 (2010). 9. T. Moore, EMBO Reports 9, S41-S45 (2008). 10. S. Sherwood, Australasian Science 30, 25-27 (2009). 11. R. Spencer, Social Science and Public Policy 44, 45-50 (2007). Conclusion
When trying to determine if global warming is fact or fiction, we must take into account evidence from all sides. Plenty of evidence exists within the science community, including skeptical opinions against global warming. While the evidence points to the existence of global warming, the cause is still widely disputed. Additionally, the media reports on other sources of evidence for global warming from different political groups. Ultimately, the world still lacks a consensus on the topic of global warming: its causes, its presence, and its effects. However, armed with the proper knowledge, we FALL 2011 17