Green Chemistry

Introduction

And man created the plastic bag, the tin and aluminum can, the cellophane wrapper and the paper plate. And this was good because man could then take his automobile and buy all his food in one place and he could save that which was good to eat in the refrigerator and throw away that which had no further use. And soon the Earth was covered with plastic bags and aluminum cans and paper plates and disposable bottles and there was nowhere to sit down or walk, and man shook his head and cried, "Look at this Godawful mess. ~Art Buchwald…1970

On Earth, we are lucky enough to have an atmosphere with constantly changing weather. The average pattern of weather over a large region, called climate, usually stays pretty much the same for centuries and will cycle in normal patterns as long as it is left alone. However, the Earth is not being left alone. Human choices are changing the planet, especially its climate, significantly. It is safe to say that the human activity that is most likely to have a large impact on the climate is the burning of fossil fuels that contain carbon (such as coal, oil and gas). Burning of these fossil fuels makes carbon dioxide gas, which is colorless and odorless. Our growing population and poor choices, sometimes due to mere lack of knowledge, have caused carbon dioxide gas to be added to the Earth's atmosphere at an alarming rate. According to the United States Department of Energy, "Fossil fuels currently represent over 85% of all energy consumption in the United States." In other words, people use fossil fuels more than any other source of energy and for more purposes than sustainable power sources can currently accommodate! Specifically, "since 1751, approximately 329 billion tons of carbon have been released to the atmosphere from the consumption of fossil fuels and cement production. Half of these emissions have occurred since the mid 1970s. The 2006 global fossil fuel carbon emission estimate of 8,230 million metric tons of carbon represents an all-time high and a 3.2% increase from 2005" (Carbon Dioxide Information Analysis Center ¹). The National Environmental Indicator Series Archives Website of Canada ² reports that the carbon dioxide emissions from fossil fuel use gross world product is over 25 trillion dollars! This rampant use of fossil fuels has caused climate change to become a major concern facing our planet. Walt Kelly's 1971 Earth Day poster, shown below (Figure 1 permission courtesy of Okefenokee Glee & Perloo, Inc.), famously sums up why this is happening, as character Pogo states, "We have met the enemy and he is us."

Figure 1

Unfortunately, even with statistical data as proof, I've found that many people, especially my high school students, don't really care about this issue. Maybe they don't take interest because they can't see it or they don't feel any personal connection to it. If only the effects of climate change were as obvious as those from acid rain or eating too many donuts, we might turn the lights off or recycle more often at home. Because, if the average temperature continues to rise, rain and snow patterns will change, the length of growing seasons will be altered, the frequency and severity of storms will increase, and sea level will rise. Farms, forests, plants and animals in the natural environment will be altered. In short, all humans will be affected to some degree, now and in the future.

My goal for this curriculum unit is to help my students understand that simple, daily shifts of habit can have a positive impact on the planet, while also entailing personal gain, specifically regarding their time and money (2 important factors in their lives). Any habit that can save them money, time and the planet is a win-win situation to me! I teach regular and honors Earth and Environmental Science courses that are a semester (2 quarters) in length. My students are mostly 9 ^th graders, although I do have the occasional upperclassman that has either failed it the first time or has simply waited to take it. This unit will be taught during the beginning of the course, particularly as an introduction to the environmental studies section (includes North Carolina state standards ³) and will run approximately 2 weeks long. The main objective is to change the way students think about the environment by making greener choices; however, emphasis will be placed on 2 of the 12 principals of green chemistry and a case study of plastics.

One part of making greener choices on an individual daily basis means choosing to purchase products that are recyclable, or better yet, reusable, so there will be less waste and a higher monetary savings long-term. My students will learn what their carbon footprint is (calculation of how much greenhouse gas emissions are causing climate change). They will explore the chemical make-up of plastic, the waste accumulated by it, and its harmful effects on the environment and the human body. Discussions surrounding 2 green chemistry principals (in particular #1: It is better to prevent waste than to treat or clean up waste after it is formed; and #10: Chemical products should be designed so that at the end of their function they do not persist in the environment and break down into innocuous degradation products) in conjunction with local (Charlotte, North Carolina) environmental justice issues will lead my students to a realization that taking care of the Earth is much more important and personal than they originally thought. Everyday actions do effect the environment and by making simple changes, they CAN make a difference and sustain their environment.