Just as James Lovelock once said, “We live at a time when emotions and feelings count more than truth, and there is a vast ignorance of science”, it is true that in this age it is increasingly important to listen to the scientific facts, as science is the best tool we have to discern whether or not climate change is caused by mankind. The term “anthropogenic” is used to describe human-made climate change and means originating in human activity. Climate change is defined in the change in global climatic patterns since the mid-20th century and is not limited to simply warming temperatures, but also extends to irregular precipitation, freak natural disaster events, record-breaking freeze spells, and much more. The heated debate about climate change must firstly be about numbers in order to gain an accurate picture of the earth’s situation and secondly must result in humanity taking action. Three causes of climate change will be explored in this paper: human fossil-fuel burning, carbon dioxide as a greenhouse gas, and the greenhouse effect’s role in increasing averaging global temperatures, and will demonstrate how climate-change is indeed caused by anthropogenic activity.
One of the most popularized forms of media that increased public awareness of climate change, or as it was previously known, global warming, is Al Gore’s documentary “An Inconvenient Truth”. The message of the film asserts that humans are causing global warming and that the effects can already be seen and will continue to devastate (Volgren, 2006). Although some sceptics claim Gore’s pictures and footage as “bogus” (Monckton, 2007), most scientists do agree that the Earth is heating up, due to the burning of fossil fuels, leading to an atmospheric increase in carbon dioxide, and support the message from Al Gore’s film. However, there is an important place for looking carefully at the numbers and discerning fact from fiction.
Perhaps the most talked about evidence of climate change is that of rising concentration levels of carbon dioxide. Carbon dioxide is a gas made from the combination of oxygen from the air with carbon deriving the man-made activities of from the burning of coal or oil, or from natural processes found in the carbon cycle. Some sceptics defend their case saying that carbon is natural and a part of life! And although this is true, we must consider that if carbon dioxide (CO2) had no harmful effects, then carbon emissions would not matter. However, the catch here is that carbon dioxide is a greenhouse gas and although it is not the strongest nor most prevalent in our atmosphere, it is significant nonetheless. The main effects of putting more of it in the atmosphere include the absorption of infrared radiation (heat) which impedes the natural flow of heat from the planet and has a warming effect. This scientific fact derived from the simple physical properties of CO2 molecules is a fundamental piece of knowledge, which drives scientists’ understanding of climate change.
The human activities that drive the burning of fossil fuels (driving, urbanization, food production, powering machinery that produces more fossil fuel, etc) undeniably have the effect of releasing carbon dioxide in the atmosphere. However, there are other greenhouse gases that are released from these activities, such as water vapor (increases as Earth’s atmosphere warms), methane, nitrous oxide and chlorofluorocarbons (CFCs). It is important to recognize all of the forms of greenhouse gases, but carbon dioxide is the gas most frequently researched and discussed by scientists. As shown in Figure 1, the rate of carbon dioxide concentration used to be steady; a flat plateau from the 1000s to the 1800s.
Figure 1: Carbon dioxide concentrations over the last 1100 years (in parts per million). This data was measured from two sources: air trapped in ice cores which show varying concentrations of carbon dioxide up to 1977 and directly in Hawaii from 1958 onwards.
Source: MacKay’s Sustainable Energy Without the Hot Air (p. 5)
In the year 1769, a noticeable shift occurred and the amounts of carbon dioxide began to increase rapidly at an exponential rate. Some sceptics would say that this recent increase in carbon dioxide concentration is a “natural phenomena”; however, by looking at the data that scientists have carefully put together, it is evident that this spike in carbon dioxide is not the workings of nature. In fact, the year 1769 marks the start of the Industrial Revolution, when James Watt patented the steam engine and is the beginning of unprecedented amounts of coal being burned from making iron and ships, heating buildings, powering vehicles and other machinery, and of course, powering the pumps that enabled more and more coal to be mine inside of hills all over Europe (Mackay, 5). Therefore, this shows that the correlation between higher amounts of carbon dioxidation is by no means an accident nor was it a part of a natural process from the preceding thousands of years.
Although the facts speak for themselves, many politicians and members of the public are still skeptical that increased levels of carbon dioxide are caused by anthropogenic activities. David MacKay dispels this myth effectively in the following argument. He demystifies the following quote by Dominic Lawson, a column-writer from the Independent:
“The burning of fossil fuels sends about seven gigatons of CO2 per year into the atmosphere, which sounds like a lot. Yet the biosphere and the oceans send about 1,900 gigatons and 36,000 gigatons of Co2 per year into the atmosphere - one reason why some of us are sceptical about the emphasis put on the role of human fuel-burning in the greenhouse gas effect. Reducing man-made CO2 emissions is megalomania, exaggerating man’s significance. Politicians can’t change the weather” (MacKay, 8)
The argument posed is appealing. However, MacKay demonstrates its misconceptions using scientific data. MacKay points out that all three numbers used by Lawson (seven, 1,900, and 36,000) are wrong and that they should be 26, 440, and 330, respectively (MacKay, 9). Although these numbers still seem in line with the sceptic’s argument, it does reduce his credibility, and there are still assumptions in his response. It is scientifically correct that natural flows of CO2 (ie: outputs from the biosphere and ocean) are larger than the additional concentrations that have spiked since 200 years ago, as shown in Figure 1. However, it is misleading to quantify and show only the large natural input of carbon dioxide into the atmosphere without talking about how almost exactly the same amount flows out of the atmosphere back into these natural sinks (ie: the biosphere and ocean). Just a simple elementary schooler could tell you that earth systems work in cycles; for example, nitrogen and water cycles through the earth, the atmosphere, the ocean, and back to earth. This simple law of nature applies to the cycling of carbon as well, and is not accounted for in charts, such as shown in Figure 1, because these large natural flows, cancel themselves out. Therefore, it is not relevant that these natural flows are greater than human emissions and sceptics such as Lawson have no argument.
Building on the first two points that new flows of carbon, onset by human activities such as burning fossil fuels, although small amounts in comparison to natural processes, are not “cancelled out” in the atmosphere, but rather stay there, we’ll move onto the effects of these increased levels and their contribution to a phenomena known as the greenhouse effect. The greenhouse effect is the “trapping and build-up of heat in the atmosphere (troposphere) near the Earth’s surface. Some of the heat flowing back towards space from the Earth’s surface is absorbed by water vapor, carbon dioxide, ozone, and several other gases in the atmosphere and then reradiated back toward the Earth’s surface” (EPA, 2013). This phenomena is closely related to increasing amounts of carbon dioxide (as previously discussed) as well as other greenhouse gases, which act as a thermal blanket for the Earth, to support life at an average of temperature of 59 degrees Fahrenheit (15 degrees Celsius). Changes to this average temperature will have serious consequences for all life on Earth as we know it (Jenkins NASA). An important aspect of the greenhouse gas is that it is true that when atmospheric concentrations of greenhouse gases increasingly become trapped in the troposphere, the average temperature of the lower atmosphere, which affects human life, will also gradually increase.
Climate scientists, physicists, university researchers, world leaders and so many more, have found the evidence and continue to do research on the nature of climate change and how humans are affecting it. So far, the factors of fossil fuel burning, increasing levels of carbon dioxide, and the greenhouse gas have been discussed; by what changes are scientists now witnessing and will these worsen? According to Amber Jenkins from NASA, although it is difficult to predict the consequences of changing the natural atmospheric greenhouse condition, the following effects are agreed upon by scientists to be likely. On average, surface temperatures on Earth seem to be getting warmer, as evidence shows that the so-called average global temperature has increased 1 by 0.6 ± 0.2 ◦C since the late 19th century (estimate given with a 95% confidence level). This increase is slightly more severe in the northern hemisphere than southern, with rapid glacier melting occurring in places such as Alaska, Greenland, the Himalaya, the Arctic ice shelf and other mountainous regions; however, Antarctica is less affected, contrary to popular belief (Dittmar and Nicollerat, 2004).
Furthermore, increasing global temperatures results in shorter and warmer winter seasons in many areas of the world. These warmer conditions lead to more evaporation and overall precipitation levels; however, individual regions vary as some become wetter (ex: flooding in United Kingdom) while others become drier (ex: Southwestern United States). These factors have a serious toll on humanity considering that water and weather our necessary for our agricultural food systems. Although some crops and plants may respond positively to increased levels of atmospheric carbon dioxide, many more will suffer from soil failure and water shortage. These effects outlined are just a short beginning to the complex, interrelated web of climate change consequences.
Beyond drought and uncertain weather events, there are several other ways that humanity will be affected by climate change. Our air and bodies of water will continue to be polluted and dirty due to the increase is atmospheric ozone due to climate change. This has tolls on human health as we may see more cases of allergies and asthma will continue to rise, especially in urban areas such as New York City, as well as longer pollen seasons which will result in more air-based allergies. Sea-level rise is also a major concern for city-dwellers and other coastal communities. Cities are more susceptible to natural disasters wrought by climate change (increased hurricanes, more severe storms, flooding, etc) and many cities do not have climate-change ready emergency plans. Thus, city life could become far more dangerous than suburban areas.
A big question in moving forward, is how can national governments as well as individuals do their part in stopping or slowing down climate change. Although there may be ways of nature that are out of human control, it is important to try to reduce our “carbon footprint” to lower levels of greenhouse gases in the atmosphere. Also, communities and countries should prepare for a “zero-carbon” or “post-carbon” world and aim to live truly sustainably. Individuals can do their part every day, on a small scale from biking instead of driving cars, and on a big scale through community organizing to make large, systematic changes to reduce climate change. Cooperation is a key part of making our planet a more liveable, healthier place in the future.
Human activities undoubtedly have a role in climate change. In a recently released “Fourth Assessment Report” by the Intergovernmental Panel on Climate Change (IPCC), the leading organization researching and processing climate data and information, it is concluded by a group of over 1,300 independent scientific experts from all over the world that more than a 90% probability that human activities over the past 250 years have warmed the planet (Jenkins, NASA). Those who wish to dismiss this statement are in denial of a truth that is inconvenient, yet unavoidable. Politicians, members of the public, world leaders, etc, must start and continue saying “yes” to taking actions to help mitigate climate change and protect humanity.
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