Anthropogenic Climate Change
This team investigated the subject of anthropogenic climate change by consulting a wide variety of academic sources. There is a rich history of concern for anthropogenic influence on climate change dating as far back as the early 1800s. Humans have continued to alter the complex natural cycles of the Earth and emit unprecedented emissions into the air causing the average climate of our planet to rise and put pressure on the ecosystems and the organisms within them, including our own species. Climate change proves to be a highly relevant global issue that will require significant amounts of mitigation through innovation and adaptation to persist through those unavoidable changes. Effects will significantly impact regions in different ways and to different degrees. By turning toward a variety of solutions early, it is possible to minimize the damage that will ensue and maintain functionality of the planet for many future generations to come. The following will explore the history of climate change, the science behind it, the effects it is responsible for, and the potential solutions.
The Early Years
The study of the Earth’s climate throughout the years has revealed the complexity and uncertainty surrounding the subject. One of the most important areas of study was that of Earth’s gaseous atmosphere. Joseph Fourier, in the 1820s, further developed the scientific understanding that atmospheric gas could “trap” heat from the Sun (Weart). Fourier recognized that the energy from the Sun’s visible light easily penetrated the atmosphere, but when turned into heat near the Earth’s surface it could not so easily escape. This effect would later be called “the greenhouse effect.” In 1859, John Tyndall began a series of laboratory experiments to determine whether Earth’s atmosphere contained such gases that could “trap” heat (Weart). Tyndall discovered that simple water vapor (a large component of Earth’s atmosphere) and carbon dioxide were very effective at trapping heat. In 1896, Svante Arrhenius, from Stockholm, was one of the first scientists to attempt to make the connection between variations in C02 levels and global temperature (Ponting 388). However, while Arrhenius’ studies focused on the low C02 levels of ice ages, his colleague, Arvid Högbom was inspired to calculate human emissions of C02 from factories (Weart). While volcanoes and other natural cycles were thought to be the primary contributor to global C02 cycles, Högbom found that human activities were contributing just as much C02. The relatively low rate of C02 emissions in 1896 was not cause for concern to Arrhenius and Högbom. At the time, emission rates were not expected to increase exponentially and the idea of a slight increase in temperature was even welcomed by some (Weart). Arrhenius still saw future warming as a possibility and published a book on climate change in 1908. At this time, coal burning and C02 emission were already much higher than in 1896, leading Arrhenius to change his timeframe for warming from several thousand to several hundred years.
Uncertainty, Skepticism and Ongoing Debate
From the very beginning climate scientists experienced skepticism. The simplistic initial calculations and uncertainty surrounding others were cause for concern in the scientific community. The controversy surrounding climate change studies combined with conflicting experiments would put the subject on the scientific backburner for a few decades. However, in the 1930s, it was widely understood that the United States and the North Atlantic region had warmed. Still, only one scientist, G.S. Callendar, predicted greenhouse warming (Weart). In the 1950s, government funding and technological advancements led to much more accurate studies. These new studies demonstrated the underestimation of earlier calculations in showing that carbon dioxide levels could increasingly build up, leading to an increase in temperature. Callendar compiled old measurements of global temperature and atmospheric carbon dioxide levels to find that they were definitely on the rise (Weart). Most climatologists were still skeptical and did not trust the older data for accurate comparisons. These same climatologists were confident that the Earth’s oceans could absorb the excess carbon dioxide. Scientific calculations and models of climate and carbon cycles were still incomplete and far too simple to explain the real world phenomenon. Even more damaging to the early adoption of the anthropogenic climate change model was the (inaccurate) widespread belief that human activity could not possibly alter the large-scale natural balances of the Earth (Weart).
Advancements and Increased Interest
While Callendar’s claims were still largely unaccepted, the curiosity of the scientific community had been revitalized. The 1960s would see the development of mathematical climate models and geological methods of determining past temperatures. These data combined with advanced atmospheric computer models showed that climate change could very well happen, and quite possibly was occurring. While these calculations predicted average global temperature increases of several degrees Centigrade within the next century, there was still no sense of urgency. The tendency was to call for further research and more accurate data (Weart).
A Shift in Social, Scientific and Political Thought
– An Era of Awareness and Increased Skepticism
The rise of environmentalism in the 1970s would revisit the idea that human activities were having negative impacts on our planet. Climate scientists were joined by those pointing out the increase in pollution of dust and smog. At this point, scientists still agreed that there was much to learn about the global climate, but that negative changes were definitely plausible. The increasing application of systems theory accompanied the acceptance of the fact that the climate is an extremely complex, dynamic system interacting with many variables. The interrelated complexity of our climate led scientists to predict negative effects in many cycles: ocean currents, droughts, storms, sea level rises and other disasters. Scientists were making advancements but the research was mostly disorganized, independent research; the call for coherency and consistency was still coming from the scientific community (Weart). Further studies on chemicals and the environment found that the levels of other gases in the atmosphere were also rising, and even damaging the protective ozone layer in some instances. The public and some politicians were beginning to grow concerned about the fragility of our atmosphere (Weart). By the late 1970s, global temperatures were continuing to rise and predictions stated that by the year 2000 we would experience permanent global warming. 1988 was the hottest year recorded up to that point and the public was now paying full attention to climate science (Ponting 389). During this year, an international group of scientists came together to warn that steps should be taken to reduce greenhouse gas emissions. This warning would spark immense opposition from corporations and anti-regulation government protesters. Millions of dollars were spent on advertisements and literature attempting to discredit or disprove the recent discoveries and warnings of climate scientists. At the same time, environmental groups were fighting just as hard, but with limited funding, to bring the issue onto active political agendas.
Looking Toward the Future
The 1990s would see the most accurate, detailed computer climate models to date that explained the current temperature increases to the rise of greenhouse gases when compared to historic levels. Further studies of C02 levels embedded in Antarctic ice cores supported computer predictions by showing that, historically, a doubling of atmospheric carbon dioxide always accompanied a 3 degree Celsius temperature increase (Weart). Around this time, the Intergovernmental Panel on Climate Change (IPCC) was formed to organize and collect the scientific community’s research on climate change and to advise governments accordingly. In 2001, the IPCC had reached a consensus that our civilization was more likely than not to experience severe global warming in the future (Ponting 389). There was still much scientific uncertainty in regards to climate, but the fundamentals had been discovered. At this point, the emphasis began to shift towards policy formation and how government’s would use the information at hand, despite the uncertainty. A 2007 IPCC report supported the previous claims that humans were changing the climate. The complex variables in the climate were already produccing negative effects: deadly heat waves, stronger floods and droughts, and temperature-related changes in species range and behavior were all increased (Ponting 389-90). Throughout the progression of climate change science, one thing that has remained constant is uncertainty and subsequent skepticism. However, as the scientific data and consensus was the most accurate and convinced of global warming, the opposition was also at its height, for fear of economic intervention and regulation. Recent temperature recordings certainly support the earlier predictions that the globe would warm by the year 2000. While uncertainty is always a crucial component of science, a growing number of individuals and governments began to lean towards the side of caution. Many people began to change their behavior, laws and regulations were strengthened, and governments around the world set up programs to cut back greenhouse gas emissions. Just as the last century has seen the advancement and progression of climate science, the next century will be the crucial time for people to make effective policies and decisions to reduce the rate of greenhouse gas emissions and subsequent global climate changes.
Where does carbon come from and where does it go?
Carbon is stored in four sinks—the atmosphere, biosphere, ocean, and the lithosphere. Fluxes allow carbon to pass between these sinks through a biogeochemical cycle called the carbon cycle. Carbon in the atmosphere is drawn into the biosphere in the form of carbon dioxide. Terrestrial autotrophic organisms extract the carbon in the process of photosynthesis. Forests constitute the bulk of the terrestrial carbon cycle, composing 86 percent of the planet’s above-ground carbon and 73 percent of the planet’s soil carbon (Sedjo). These organisms eventually become food for heterotrophic animals or die and decompose, transferring the carbon to the lithosphere.
The ocean carbon sink is the largest of the carbon sinks. Carbon dioxide enters the water via diffusion processes and forms carbonate and bicarbonate. Biotic marine life, primarily coral, clams and oysters fix this carbonate and bicarbonate to produce calcium carbonate that forms their shells. As these creatures die their remains fall to the bottom of the sea as sediment to become part of the lithosphere. The Milankovitch Cycles play an important role in the functioning of the carbon cycle and the rates of exchange that occur between sinks. There are three major planetary events occurring influencing these changes. First, Earth’s elliptical orbit causes 100,000 year climate change cycles, second Earth’s axis tilt changes by a degree or two every 40,000 years, and third Earth’s orbital plane relative to the sun changes in 21,000 year cycles (Friedman, 161). Intensified sun due to Milankovitch Cycles has caused massive dead zones and sediment build up helping to lock atmospheric carbon into fossil fuels and sedimentary rock in the lithosphere.
Carbon returns to the atmosphere through several ways—cellular respiration, aerobic and anaerobic decomposition, volcanic activity, degassing of oceans, and combustion. Combustion is most responsible for returning carbon to the atmosphere and is skewing the global carbon budget. Atmospheric carbon in the 1700s was 578 billion metric tons. Presently it has risen to roughly 750 billion metric tons (Przyborski).
Why are greenhouse gases important?
While the ozone layer works to block ultraviolet radiation, greenhouse gases are infrared absorbing gasses and about 90 percent of solar radiation is absorbed (Pidwirny—The Greenhouse Effect). This absorption of solar radiation helps maintain the 6 degree C range that separates warm and cold interglacial periods (Friedman, 162). Presently we are experiencing a warm interglacial cycle as per the Milankovitch Cycles, which is helping to keep the average temperature here on Earth at roughly 15 degrees C and thus the reason there is life on Earth (Ponting, 385). Without these gases Earth would be cold and uninhabitable with “an average temperature of minus 18 degrees C” (Zachary Smith, 113).
What are greenhouse gases?
Greenhouse gases are carbon dioxide, methane, nitrous oxide, and Chlorofluorocarbons (CFCs), as well as a variety of other trace gases including ozone and water vapor. There is an inverse relationship between the amount of each greenhouse gas present and the intensity of these gases.
Carbon dioxide is the largest component, accounting for up to two-thirds of the total effect of greenhouse gas emissions (Ponting, 387). Average temperature ice core data shows when Earth has gone from glacial to interglacial periods—those 6 degree C changes—carbon dioxide concentrations have changed by only 180 ppm (Friedman, 162). The world has been stable for approximately 10,000 years at the pre-industrial revolution levels of 275 to 280 ppm, but it has now rocketed to 380 ppm “where it has probably never been for twenty million years” (Friedman, 163). Carbon dioxide levels in atmosphere now 30 percent higher years and increasing 200 times faster than any time in last 800,000 years (Ponting, 394).
Methane is another important and relatively plentiful greenhouse gas. Methane is 20 times more infrared absorbing than carbon dioxide and accounts for a fifth of the greenhouse effect (Ponting, 387). Core data shows methane levels 130 percent higher than any time in the last 800,000 years (Ponting, 394). Nitrous oxide makes up only 5 percent of greenhouse gases but is 120 times more powerful than carbon dioxide (Ponting, 388). CFCs and other aerosols follow a similar trend in that they are thousands of times stronger than carbon dioxide and also reduce the amount of stratospheric ozone that filters ultraviolet radiation due to the chlorine contained in the chemical. These gases make up 12 percent of the total greenhouse gases and are expected to decline as a result of the Montreal Protocol agreement banning their use (Ponting, 388). Many of the trace gases such as ozone and water vapor have yet to be fully understood in terms of their enhancing capacities (Pidwirny).
What do increasing greenhouse gas levels mean?
Rising greenhouse gas levels are substantially influencing climate and causing temperature increases. The twentieth century witnessed an average increase of 0.55 degrees C in equatorial regions (Zachary Smith, 114). Parts of Europe and higher latitudes saw more dramatic increases though with averages as high as 0.95 degrees C (Ponting, 388). The twentieth century has been recorded as the warmest in the last millennium, with nineteen of twenty of the warmest years occurring after 1980 and the four warmest years ever recorded in 1998, 2002, 2003 and 2004 (Ponting, 389).
Impacts of Climate Change
2007 IPCC Report
As presented in the 2007 report from the International Panel on Climate Change (IPCC), accelerated global climate change is well under way and human activities, especially the burning of fossil fuels and deforestation, are “very likely” to blame. Intergovernmental Panel on Climate Change. (2007). The climactic changes cannot be predicted exactly, but will be felt by all ecosystems and will affect life on Earth to varying degrees. The predicted changes run the gamut from somewhat minor to catastrophic. This paper will focus narrowly on four areas: oceanic changes, agricultural shifts, shifting centers of human population, and weather changes. Because the altering of the Earth’s climate system is happening very rapidly in evolutionary terms, yet slowly compared to the social changes that one may experience over a normal human lifespan, it is possible for people who are not informed of the science of climate change to have no direct knowledge of the massive problem that we humans are creating for future generations. Climate change is not something that can be readily “seen.” If we are to alter the current path, which by almost all accounts is one of vanishing resources and dangerous climatic change, it is imperative that all people be informed of the causes of the problem and ways that each of us can move toward a more sustainable way of living. http://www.youtube.com/watch?v=lUK4dK82nvk
The Earth is 75% ocean. It only seems logical that the oceans would be integral to the overall health of the planet. Indeed, we now know that the Earth’s climate is greatly influenced by our oceans. The water in the sea serves as a sponge for carbon dioxide, (CO2) and has long helped to create the proper balance of CO2 in the atmosphere, moderating the temperature of the planet and making it hospitable to an amazing diversity of life forms. Since the industrial revolution, we have greatly increased our output of CO2 into the atmosphere. The ocean has absorbed much of this extra CO2 and has, in the process, become more acidic. Coral reefs are showing dramatic loss of life due, in great part, to the acidification of the sea. Microscopic organisms that serve as the start of the food chain in the ocean are also in peril. Oxygen is also being depleted in the oceans due to a complex series of events that put the balance of our oceans at risk. see http://www.youtube.com/watch?v=OlJfWnlwUFg
The flow of the water itself is known to be effected by temperature changes. Ocean currents are at risk of being altered due to temperature changes. Northern Europe is kept warmer than it would be, based on its latitude, by the currents of the ocean. This is one location on Earth that would actually get much colder due to “global warming.” The polar ice caps are melting at an increasing rate causing sea level rise and further increased temperatures due to less ice reflecting light (heat) back into the atmosphere. Rising temperatures in the ocean also increase the volume of the water (hotter water expands), thus leading to further sea level rise. Island nations are the first to experience the effects of sea level rise and some will see the loss of all their land within the next two generations. Oceanclimate.org. 10 Mar 2011. The World Ocean Observatory. http://www.oceanclimate.org/
Population shifts are already happening due to a rather new, but sure to grow phenomenon: environmental refugees. Ten percent of the world’s population lives on the coasts. In the United States, a full fifty percent of the population lives within fifty miles of the coast. It is not difficult to imagine that a rising sea will displace many millions of people in a relatively short period of time. A growing shortage of freshwater is also likely to shift population away from arid areas that have seen booming population growth such as the desert southwest of the United States. A cruel irony looms: too much unusable water from the sea and not enough freshwater on the land. Temperature changes and increased levels of atmospheric CO2 will cause already hot areas to become hotter, dryer and perhaps unlivable. Agricultural output, which has boomed over the last century enabling astounding population growth (1.5 billion in 1900 to 6.91 billion 2010 US Census Bureau), will be greatly challenged by the shifting climate.
Large scale agriculture contributes to global climate change through altered land use (deforestation) and the heavy use of petrochemicals which generate greenhouse gasses. It is predicted that the poorest countries will experience the most dramatic declines in agricultural output. Many are located in regions already hot and dry and unable to withstand even a moderate increase in temperature. This may lead to population shifts as mentioned earlier. Agricultural practices are going to have to change in order to deal with the problem they helped to create. The “growing” of animals for human consumption is responsible for 18% of greenhouse gas emissions. According to a 2006 United Nations report, “Livestock now use 30 per cent of the earth’s entire land surface, mostly permanent pasture but also including 33 per cent of the global arable land used to produce feed for livestock. As forests are cleared to create new pastures, it is a major driver of deforestation, especially in Latin America where, for example, some 70 per cent of former forests in the Amazon have been turned over to grazing.” With a growing population to feed, we must adhere to the most efficient way of eating that has the least environmental impact. A plant based diet, according to a report by the United Nation’s International Panel for Sustainable Resource Management, is the way to go.
When speaking about global climate change, most people think of weather changes having to do with the Earth getting hotter. Because we often hear climate change referred to as “global warming,” many people point to record snow storms as “proof” that global climate change is not real. The terms climate and weather are not interchangeable. Climate occurs over a long period and weather is seasonal. While the Earth is trending hotter, periodic unusually cold periods are not exempt from climate change. Collins, William, Robert Colman, James Haywood, Martin Manning, Philip Mote. "The Physical Science behind Climate Change." Scientific American 7.19 (2007) Web 16 Feb 2011 Climatologists’ modeling of Earth’s weather patterns as they relate to climate change indeed show that the severity of weather events is likely to increase, including cold weather events. Droughts will be more common as will floods. Record heat waves may follow an extremely cold winter. Weather patterns are likely to be more erratic and extreme, thus having a greater impact on the long term habitability of life on the planet.
As future generations look back, what will they say of their elders, of us? The best that could be said of any generation is that its leaders and its ordinary citizens had the courage to look critically at the current state of affairs and do their best to improve upon what was handed down to them. Hundreds of scientists from around the world have spent long careers studying the impact we humans are having on the planet. The data is overwhelming. The future we are looking into can also be overwhelming. It is up to each one of us to change our behavior and decide that we are willing to do whatever it takes in order to leave the Earth livable for the next thousand years. None of us will live long enough to see the outcome and that is probably the worst thing about the situation. If we had to live forever, we’d be doing more right now.
Humans carry themselves as if their actions and decisions have no effect on the world around them. We know that our need for and addiction to fossil fuels has a detrimental effect on the environment, that effect is known as global warming. Warming and cooling of the Earth’s atmosphere is not uncommon. It is a natural cycle that has been occurring for millions of years in Earth’s history. However, over the last one hundred years or so, temperature has been on a steady rise along with deposits of gases like carbon dioxide and methane. These excess gases capture the radiated warmth of the sun to the point where it raises the temperature of our whole world’s atmosphere over one degree Fahrenheit. That may not sound like a lot but it is more than enough to melt our polar ice caps, lead to rising sea levels, flooding and uncomfortable temperatures. (Neil et al., 2007).
All these effects are caused by the increase in greenhouse gases that come from burning fossil fuels in factories, cars and power plants. If we could find another way to power our homes, our logistics systems and our modes of transportation, we would be in much better shape for the future. That is why scientists have been investing time and money into new technologies such as hybrid technology, hydraulic power, wind turbines, solar panels, hydrogen fuel cells and more. All of these sources of energy use no fossil fuels or dramatically cut down on the need for them but they each have their set-backs. (Brown, 2003).
Most Americans know the joys and pains of owning an automobile. People get a rush from a sudden burst of speed from their powerful internal combustion engines and the feeling of freedom but pay a price at the gas pump. Hybrid and hydrogen fuel cell technology could change all that. Hybrid technology uses a joint system between a gasoline powered engine and an electric motor. The gas engine drives the car at normal speeds but when slowing down and driving at less than 25 miles per hour, the electric motor takes care of the rest. The stopping energy of the car recharges the batteries in the car driving the electric motor. This allows the car to use less gasoline and still have the travel radius of a normal car. However, these cars are fuel efficient and not high on power or performance. Hydrogen fuel cell vehicles are even more advanced. Instead of refined fossil fuels put into the tank, compressed, liquid hydrogen is used for fuel. The hydrogen combined with oxygen from the air makes electricity to power the car. Using hydrogen fuel cell cars is perfect for our way of life because it fits the niche of gasoline, but it will never run out because hydrogen is the most abundant element in the universe. Also, the only emission is water, nothing harmful to the environment. (Midili and Dincer, 2008).
Electrical Source Alternatives
Hydraulic power or power provided by dams is another option. Water is held up by the large dam and let through a man made outlet. Through this outlet, the water spins turbines that collect electric energy. It’s a novel idea that’s worked for a long time. However, its effects on the environment, especially fish, can be detrimental. It cuts off rivers and can affect temperatures in the standing lakes behind the dams. Fish cannot get back to their native waters to mate once they reach maturity. Most of all, dams only work where there is a large supply of running water. How can the deserts harvest renewable energy?
Solar panels succeed where dams cannot. Solar panels take the immense power of the sun and turning it into usable power. Photovoltaic cells, made of silicon, within the panel take the emitted photons from the sun and convert them into electrons. The fall back of solar panels is that they have a band gap. They can only use certain wavelengths of light to create energy. They only collect during the day, so at night no energy is being harvested, only used. Solar panels are much more practical when powering something small like a calculator. In order to power a building, the whole roof would need to be covered by these panels and they are not light or cheap to say the least. (Scott and Toothman, 2011).
Wind turbines also work in open areas like deserts or open planes. More simple versions have been used as early as 200 B.C. Giant, sky-scraping structures tower over prairies with a white glow about them. The moving wind mill coverts the kinetic energy of the wind into mechanical energy. The smallest turbines are used for applications such as battery charging or auxiliary power on sailing boats, while large grid-connected arrays of turbines are becoming an increasingly large source of commercial electric power. In order to harvest enough power to run cities, hundreds of giant turbines would need to be placed wherever possible and that is neither practical nor appealing to the eyes. Also, whenever the wind is not blowing at a strong, steady pace, no power is being created.
All these resources and technologies help with our global warming problem. They don’t use fossil fuels but rather harness the power of the Earth. However, they don’t supply the degree of power that fossil fuels do, nor do these solutions work in all regions and conditions like fossil fuels. The reason we are still killing our atmosphere is that we can’t find a better, stronger alternative to fossil fuels. Once we find a better, practical, renewable source of energy and the government stops dealing so much with oil companies, our society’s way of life seems much brighter in the future.
A., Neil, Jane B., Lisa A., Michael L., and Steven A. Biology: A P*. Edition 8th. 2007. Print.
Aldous, Scott, and Jessika Toothman. "How Solar Cells Work." Modified
March 27, 2011. How Stuff Works. Accessed March 27, 2011. Web.
Brown, DA. "The importance of expressly examining global warming
policy issues through an ethical prism." Global Environmental
Change-Human and Policy Dimensions. 13.4 (2003): 229-234. Print.
Collins, William, Robert Colman, James Haywood, Martin Manning, Philip Mote. "The Physical Science behind Climate Change." Scientific American 7.19 (2007). Web.
Friedman, Tom. Hot, Flat, and Crowded. New York: Picador, 2009. Print
Intergovernmental Panel on Climate Change. (2007). Climate change 2007: The physical science basis. New York, NY Retrieved March11, 2011, from http://ipccwg1.ucar.edu/wg1/Report/AR4WG1
Kimball, John W. “The Carbon Cycle.” Modified January 6, 2011. Accessed March 22,
Midilli, A, and I Dincer. " Hydrogen as a renewable and sustainable
solution in reducing global fossil fuel consumption."
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY . 33.16 (2008): 4209-4222. Print.
Pidwirny, M. "The Greenhouse Effect". Modified May 7, 2009. Fundamentals of Physical
Geography, 2nd Edition. Accessed March 22, 2011.
Ponting, Clive. “A New Green History of the World: The Environment and the Collapse of Great Civilizations.” New York: Penguin, 2007. Print.
Przyborski, Paul. “The Carbon Cycle” Modified March 25, 2011. NASA. Accessed March
Sedjo, Roger. “Part II. How does carbon move in and out of the atmosphere?” Oregon
Wild. Accessed March 22, 2011.
Smith, Zachary. The Environmental Policy Paradox. Upper Saddle River: Pearson
Education Inc., 2009. Print.
“Ocean Climate.” Modified March 10, 2011. The World Ocean Observatory. Accessed March 10, 2011. <http://www.oceanclimate.org/>.
2010 US Census Bureau
Weart, Spencer. The Discovery of Global Warming. The American Institute of Physics. July 2009. Web. May 2011. <http://www.aip.org/history/climate/index.htm#contents>
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