"Global warming… what a crock. I've been in the business for thirty-five years and I can tell you that there is no such thing. It's just a lot of talk. I can tell you for a fact that I've put in more furnaces than air-conditioning units in the past year. I've been around a long time," he said with the frost of his breath still slightly visible coming from his animated voice. "Does this seem like global warming to you?" He gesticulated into the air. "Anyways, I can tell you that I know that there is no such thing. The weatherman can't even tell you what the weather is going to be tomorrow. This winter is as cold as any other winter if not colder."
"Actually," my enlightened girlfriend responded, "There is a lot of scientific evidence that global warming in fact results in extreme weather changes, either hot or cold. The current melting of the glaciers is a powerful indication that the Earth is warming-"
"That global warming is just a bunch of malarkey." John interrupted. "I've been in this business a long time and anyone that tries to tell me otherwise is going to get a piece of my mind."
"You're out of your head," I thought. His message that global warming is a myth was absurd but I didn't know how to correct his misconceptions but I thought of my students and wondered how many of them were misinformed about global warming. My students are voting age or soon to join the ranks of the voting public. I want to make sure that they are informed citizens about the issues related to global warming and that they can help to inform others. Now I hope to give a voice to others who find themselves in situations where the science of global warming is discredited by anecdotal evidence and provide them with the scientific evidence.
The science is absolutely clear that global warming is occurring. Temperatures are climbing and the number and severity of storms are increasing. The polar ice caps are melting and the ocean levels are rising. Extreme hot weather as well as extreme cold weather becomes more prevalent. The weather is unpredictable because it is a chaotic system. The extreme increase in greenhouse gases, resulting primarily from burning fossil fuels, is the cause of these potentially catastrophic changes in the Earth's climate.
Overview
In these pages I will attempt to present the physics of global warming, explain the most likely consequences of global warming, address the chaotic nature of weather and why it is difficult to predict and discuss the current scientific theories about the possibility that stress on the climate system of our current rate of production of greenhouse gases could possibly result in a catastrophic change in our climate.
The science is unequivocal that there is global warming and that the Earth's average temperature has increased by nearly a degree Celsius in the past 150 years and the carbon dioxide levels have increased 35%. The energy increase from global warming is 0.1W/m 2 per year on the Earth's surface. In 100 years, at the current rate, the Earth's climate system will have increased by 3%, and the rate is increasing. This increase is enough to potentially destabilize the Earth's relatively fragile system.
Although there are many uncertainties about the specifics of global warming, it is clear that it is one of the most pressing issues facing humankind. It is a global issue that must be addressed and mitigated with a sense of urgency that may be unprecedented. The scientific community is beginning to mobilize on this issue and it is essential to create a global, public awareness to address this issue. There is much that is uncertain about the exact implications of global warming but what is clear is that the human production of the greenhouse gases is growing at an alarming rate, is as high now as it has been in 3.5 million years and will exceed the level at any time in the past 50 million years when it doubles the pre-industrial levels in the next 40 to 200 years. Increased greenhouse gases result in a rise in temperature. A rise in global temperature will result in a rise in sea level, an increase in the severity and frequency of storms, drastic changes in rainfall distribution and a change in ecosystems. In addition, there is the possibility that climate may be a chaotic system and that these effects might be magnified and culminate in extreme changes in climate such as precipitating the return of an ice age as some scientific weather models predict.
The primary lesson here is that, although there is a lot that we do not know at this point, the evidence indicates that globally we had better err on the side of caution. Global warming has the potential to annihilate the human race by making our relatively fragile Earth uninhabitable. We must be responsible to our children and our children's children. Are we facilitating their demise by our irresponsible rampant production of greenhouse gases? How do we control our emissions of greenhouse gases before it is too late? Scientists are adamantly predicting that we are approaching a critical point of no return. How do we mitigate this crisis?
The good news is that if we act quickly and with single-minded determination that we do, in fact, have the scientific means to address, reduce and potentially control this problem. Limiting global warming will take a concerted global effort. However, there are enough technological alternatives to the greenhouse producing gas energy sources upon which we are currently dependent for humankind to curb this trend. It is inevitable that the level of carbon dioxide, which is the predominant human made greenhouse gas, will double from the pre-industrial age. The question we are facing is whether that will happen in forty years or two hundred. We are not going to be able to reverse this trend, but the goal is to stop this runaway process and limit the future damage that we are going to inflict upon the planet as a result of global warming. We can not change the past but we do have the ability to control the future. So, now is the time to act. If we do that then given the human ingenuity to solve problems we will buy ourselves enough time to find creative solutions to this problem. It is apparent now to anyone who is able and willing to interpret the scientific evidence that the continued flagrant, irresponsible and unwise production of greenhouse gases will have damaging if not fatal consequences for humanity. So what can we do? Well, first we must understand the problem.
It is also my hope that any teacher who is interested in the issue of addressing the problems of global warming will find within this unit the background scientific information to address the subject in their classroom. This unit is intended to provide relevancy to the study of global warming for high school physics classes and general science classes. The unit can be taught as a capstone on thermodynamics, conservation of energy and waves and the information on climate can introduce chaos theory. The level of instruction can be adjusted to make the unit applicable for general science by presenting the conceptual issues without the mathematical explanation. The primary goal of the unit is to make our students better global citizens who are able to make informed decisions based on current scientific knowledge and to counteract the misinformed myth that global warming does not exist. An informed citizenry is necessary for the protection of our global health. It is my sincerest hope that this unit will be accessible to anyone who wants to become more aware of the scientific issues about global warming.
Specifically this unit is written with my Peabody High School students in Pittsburgh, Pennsylvania in mind. My physics students are juniors and seniors and are among the best students in the school. My general science students are freshmen or are taking the class for the second time because they failed as freshmen. Peabody is 95% African American, 4% white and 1% other. It is a low socioeconomic school in which 98% of the students receive free or reduced lunches and a low performing school in which only 4% of the students passed the state PSSA math test and 20% passed the reading and writing test.
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