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Global WarmingThe Hottest Debate of the Decade

kriSten Flint ‘14

worLD

Global warming has been a point of contention in our society for years, and the extreme views

from both sides of the argument have transformed the subject of global warm-ing from a factual theory into a mythical idea. At one extreme, those who con-sider themselves “green” bemoan the tragedy that man is causing our planet’s climate to heat up while the other side of the debate refuses to believe any part of the global warming theory. Behind both opinions, there is often confusion, misunderstanding, and a general lack of knowledge. The theory that global warming has anthropogenic causes has existed for over a century, and scien-tists have collected evidence on global warming for over fifty years. In spite of the evidence, the public generally lives in the dark, constantly wonder-ing if global warming is fact or fiction.

Global warming is the increase in the Earth’s temperature caused by in-creased emission of greenhouse gases into the atmosphere (1). The greenhouse

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 Swed-ish 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 skep-tical as many other factors could also affect global temperature. Since Arrhe-nius’ paper, the global warming discus-sion has grown convoluted as both sci-entists 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. ScienceThe greatest source of confusion

about global warming comes from the media. During periods of natural disas-ter—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, poli-tics, 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 re-searching 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 documenta-ry made over $49 million, reaching mil-lions of people and starting more con-versations 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.

DArtmouth unDergrADuAte JournAL oF Science16

papers published in scientific maga-zines because it reached such a vast au-dience (4). The politician replaced the scientists as the informer of the public.

This mixing of sources from sci-entists and politicians has caused the media to convey a greater sense of un-certainty about global warming. PhD student Jessica Durfee and associate professor Julia Corbett from the Uni-versity of Utah department of commu-nication 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 sug-gested some uncertainty about global warming. Several people read each ver-sion, which differed in the amount of controversy and context they included, and then took a survey about their cer-tainty of global warming. Durfee and Corbett found that scientific context led to the greatest certainty about glob-al warming, and controversy caused greater uncertainty about the issue. Furthermore, added controversy be-tween the differing scientific and politi-cal opinions diminished the perceived importance of global warming. (3)

The Internet provides anoth-er source of confusion about global warming. Scientific articles, news ar-ticles, and blog entries found on the Internet all provide accounts of global warming but have dramatically differ-ent levels of credibility. However, the average Internet user does not take the credibility of his or her sources into ac-count. 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 al-ways provide clear, high-quality facts and evidence for global warming. (1)

Scientific EvidenceThe global warming contro-

versy also exists within the scien-tific 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

how global warming has occurred.Scientists have a wide array of evi-

dence to support the theory that man has caused global warming. Firstly, evidence from meteorological stations that record the global mean tempera-ture 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 dur-ing a given year. By plotting the tem-perature information with the mea-surements of carbon dioxide, scientists have found that the two have a positive correlation. Both temperature and the amount of carbon dioxide in the atmo-sphere 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 re-cap of changes that had occurred since 2005. Within those two years, the rate of polar ice melting increased, Antarc-tica weather balloons steadily warmed, and the sea level rose (6). Earth scien-tists 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 pri-mary factor causing global warming.

Skeptical scientists point to evi-dence 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 re-search units that provide the global mean temperature series are “hiding data and falsifying scientific evidence on global warming.” More substan-tively, the skeptics also point out that the temperature data does not cover much of the world’s geography, and the temperature data is negatively af-fected by urban expansion in what is known as the “heat island effect.”

Skeptics also accuse climatologists who predict future global warming of leav-ing out the impact of natural process-es, 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 creat-ing 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 surround-ing the global warming debate, much of the public only takes from the me-dia 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 gen-eral, 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, hu-mans may further disturb the ecosys-tems. 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, nulli-fying the benefits of a longer growing season. The temperature increases will bring hotter temperatures in the sum-

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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 esti-mate 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 va-por also acts as a greenhouse gas, trap-ping 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 car-bon 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 in-tensifies 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 at-mosphere. 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).

ConclusionWhen 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 skepti-cal opinions against global warming. While the evidence points to the ex-istence of global warming, the cause is still widely disputed. Additionally, the media reports on other sources of evidence for global warming from dif-ferent 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

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).