No issue exists in the world today that is more salient to scientists and policy makers than the real and potential human influence on weather and climate. Since I was born in 1941, world population has exploded from 2.3 billion to more than 6.7 billion persons. Indeed our proclivity for breeding is far more prolific than the lowly rabbit's with its not-so-well-deserved reputation for uninhibited parturiency: British scientists revealed in the early 1970s that humans were 100 times more lecherous than the hare. Coupled with the exponential pullulating of humans is the concomitant expansion of our practical activities in both agriculture and industry. Enabling this phenomenal growth is technology, which to date has been based on the combustion of carbon-bearing fossil fuels (coal, oil, and gas), virtually all of which were stored in the Earth's crust until A.D. 1300. Four centuries later, on the eve of the Industrial Revolution, Londoners consumed one thousand tons of coal per day, but at that time few other world citizens could claim to have had the "pleasure" of that experience. For the next 150 years, Britain would have a near-monopoly on the Industrial Revolution, and it would be the British who best understood the connection between industrial smoke, bad air, black fogs, and the pungent smell of sulfur. At the end of the nineteenth century, the Industrial Revolution had invaded much of Eurasia and the United States, and until 1950 coal was king. By 2004, humans worldwide consumed ten billion metric tons of oil-equivalent energy, 26 percent of which was coal. Burning these fossil fuels released more than 23 billion tons of the major greenhouse gas, carbon dioxide (CO2). In other words, burning a ton of fossil fuel emitted an average of 2.3 tons of CO2.
Recent research indicates that human modification of the weather may have roots much older than those of the Industrial Revolution. Agriculture originated as a primary economic activity in the eastern Mediterranean 11,000 years ago. There is some evidence that it arose simultaneously in Southeast Asia and shortly thereafter in northern China. It evolved much later in the western hemisphere. Even though human populations never exceeded 200 million until the Hellenic Era (323-146 B.C.) during the passage of those nine millennia, every crop now known to humans had been domesticated somewhere in the world. Huge tracts of forest had been cleared, rice paddies had been flooded, grasslands had been burned, and irrigation waters had been dispersed along mature river basins. In the process, massive quantities of human-induced greenhouse gases were released into the atmosphere. In a seminal article in Scientific American, marine geologist William Ruddiman revealed that humans may have avoided an ensuing ice age by raising the levels of carbon dioxide (CO2) and methane in the atmosphere by clearing up to 25 percent of the Earth's macrofloral natural biomes and replacing them with microfloral crops. The result of this activity was an increase of CO2 alone from 160 parts per million (ppm) in 6000 BC to 240 ppm in 1800, four decades before the rapid diffusion of the Industrial Revolution from Great Britain to the European continent (Ruddiman 46, 48-53).
CO2 is the best known "greenhouse gas." The Greenhouse Effect is a concept involving the atmospheric transmission and absorption of shortwave sunlight by the Earth's surface that in turn re-radiates long-wave heat energy back to space. There the combination of atmospheric CO2 and water vapor (another greenhouse gas) absorbs some of the outgoing terrestrial radiation, which raises the temperature of the Earth. Without the Greenhouse Effect, Earth would average a temperature of minus 4oF. Although CO2 attracts the greatest attention for its "global warming potential," it has plenty of company in the atmospheric environment. In reality, there are at least thirty greenhouse gases, the most conspicuous of which are the already-mentioned water vapor, methane (CH4), nitrous oxides (N2O), hydrofluorocarbons (HFCs), tetrafluoromethanes (CF4), sulfur hexafluorides (SF6), and ozone (O3). All of these are more potent to global warming than CO2: CH4, for example, possesses 21 times the potency of CO2 and SF6 is 23,900 times more powerful. In addition, except for CH4 and a few of the HFCs, they all remain in the environment for far longer periods than CO2. CF4, for instance, persists for 50,000 years! Thankfully, except for water vapor, with its ironic property to both absorb and reflect sunlight, and methane, which lingers less than 15 years, the remaining gases are yet far less influential. The huge volume of CO2 and its 50- to 200-year lifetime in the atmosphere, however, ensure its "celebrity status" among greenhouse gases for centuries to come.
Almost 20,000 years ago, the world's average temperature was 9oF cooler than today's 59oF. The time marked the end of the most recent ice advance that Americans refer to as the Wisconsin glacial and Europeans call the Würm. Accordingly, the majority of Earth's warming occurred well before the Agricultural and Industrial Revolutions and when human beings were fewer than 10 million. Since the inception of the Industrial Revolution (as early as 1700), Earth has experienced a global warming of a mere 1.13oF and its primary cause has been an increase of atmospheric CO2. Yet, 56 percent of all CO2 freed by human actions since that technological change is still in the atmosphere, and, "directly or indirectly," this may account for 80 percent of all contemporary global warming (Flannery 28).
Based on our pitifully brief human lifetimes, climate change is painstakingly slow. With the passage of ten or twenty years, laypersons barely notice any average temperature change. Between 1930 and the 1970s, in fact, the globe's average temperatures plateaued and periodically declined. Between 1960 and 1964, when I was a college undergraduate, pundits were more concerned about "global cooling" and an ensuing ice age than they were about the inexorably rising CO2. Indeed, one of the modern arguments against human-induced global warming is the paradox of global cooling between 1930 and the 1970s, a time when the volume of CO2 soared. It turned out that rampant, unabated coal-particulate pollution increasingly reflected shortwave sunlight back into outer space, thus causing the drop in temperature. By the 1970s as "scrubbing technology" cleaned the air of particulates and aerosols, and the world converted from dirty coal to clean oil and gas, the atmosphere became relatively clean again, permitting the Earth's surface to absorb more of the solar spectrum, thereby permitting a reversal of the previous temperature trend.
Whether slow or fast, natural or human-caused, global warming in the early twenty-first century is a fact. What is not yet proven, but is nevertheless relevant, is precisely how much of the warming is brought on by human action. Over the next hundred years, whether Earth's average temperature increases a single degree or five degrees (F), the fates of hundreds of thousands of species and perhaps millions of human beings will be determined. Then again, 99.99 percent of all species that have ever existed on our planet are extinct: extinction is a way of life. Part of the reason for extinction is a species' inability to cope with environmental change, and modern society and existence are no exceptions: "At least one of every five living things is committed to extinction at [already] existing levels of greenhouse gases. We know that our planet must heat [up] by 2oF this century, come what may. 'Business as usual' will commit us to a 5oF increase in temperature" (Flannery 173, 183). Such dramatic changes cannot fail to alter the habits of life on Earth.
Disruption of habitat has always been a key to species eradication, and the most important herald of habitat destruction has been weather and climate change. Global warming is clearly evident in Alpine ecology. Composing only 3 percent of Earth's surface, Alpine habitats, which are located between treeline and snowline, environ more than 10,000 species. Since World War Two, the upslope retreat of Alpine ecosystems and their wildlife habitats has taken place at the rate of 20 feet per decade because of the melting of their glaciers and permanent snow fields (Flannery 173-174). The changes, however, are not restricted to the mountains. Already on U.S. flatlands and rolling plains, certain species of birds, including populations of the eastern meadowlark, the red-headed woodpecker, and the green heron, have fallen by half because of habitat loss, global warming, and competition from introduced species. Honey bee populations have declined by 40, 50, and 60 percent in many areas of the United States. No one knows why, but it may relate to mite infestation, disease, pesticides, or climate change. "A report from the World Resources Institute (WRI) in 1998 suggested that as much as 60 percent of the earth's coral reefs are threatened by human activity," such as overfishing, sedimentation, pollution, and marina developments. Other causes are coral bleaching, rising CO2 levels, and disease. "Scientists have said that as much as 95 percent of Jamaica's reefs are dying or dead" (Shah 1). All over the world, whole species of frogs have gone extinct. Even Antarctic krill are taking a beating, with their populations descending at a rate of 40 percent per decade in the last thirty years. That which is of concern here is that they represent a species that is very near the foundation of the globe's food web. In each of these disruptions, global warming may be contributing to what is going on.
I was honored to serve as leader of this HTI seminar. From the first week, the participating Fellows realized the importance of our topic and enthusiastically seized the opportunity to learn and elaborate on the myriad subjects. A few, but not all, of our Fellows were scientists, and they were selected to develop curriculum units that were focused on meteorology, weather, and climate classification. The majority of our Fellows, however, were social scientists, and they took up the challenge of analyzing the subjects of climate change, global warming, and the real and potential role of humans in the process. No one who participated in this seminar, least of all I, left it without a sense that, like the climate they studied, they too had changed.
Deborah Dabbs, our intrepid Seminar Coordinator, teaches Creative Writing to sophomores, juniors, and seniors at M. B. Lamar High School. Her unit is a clarion call to raise the awareness of the complexities of global warming among adolescents while they are still impressionable and idealistic. She argues that our youth can then "multi-level-market" their knowledge to their parents, relatives, and friends, thus creating a more knowledgeable "extended public." Students would inculcate the subject matter through the creative writing of papers, plays, and novellas that deal with weather and climate change.
Shelly Brown, our kindly but stouthearted Writing Mentor, teaches a wide variety of subjects (reading, math, spelling, English, Science, and Social Studies) to fourth graders at John E. Codwell Elementary School. Her unit focuses on the elements of the weather and the controls of climate. Her lesson plans deal with student involvement in weather forecasting, the practical analyses of daily weather, and how those elements feed into long-range climate patterns.
Elizabeth Ortiz teaches the "basics" to bilingual pre-kindergarteners at Brookline Elementary. A native of Colombia, Elizabeth designed a unit that is aimed at teaching introductory weather and climate to-in her own words- "little ones." Her lesson plans deal with how to clearly present common Earth-Sun relations (rotation, orbit, and inclination) to children five and younger, many of whom have yet to master English.
Francisca R. Sorensen teaches science and ESL to fifth graders at Dora B. Lantrip Elementary School. Born in Mexico, Francisca created a unit that thoroughly covers atmospheric moisture, lapse rates, and violent storms. She writes with a smooth, understandable style that reduces complex notions to their simplest essence. The unit is filled with details and reveals excellence in understanding the science of weather. Her lesson plans are aimed at fifth graders but are also useful for older pupils.
Jose Tapia teaches elementary science to fifth graders at Love Elementary School. As the work of a true scientist, Jose's unit reveals his gifts at conveying potentially difficult concepts in simple language suitable for pupils between nine and twelve years of age. His work is copiously illustrated with figures of his own original design, and his lesson plans prove that exposure to such subjects as atmospheric composition, Earth's energy budget, the Greenhouse Effect, air pressure, and atmospheric motion can be both educational and fun.
Selendia Terry teaches reading, language, science, social studies, and writing to fourth graders at John E. Codwell Elementary School. Her unit is a readable survey of the eons, eras, periods, and epochs in geologic time, with emphasis on climate change. One of the most difficult concepts for young persons to master is the concept of time: they themselves are ageless, and the oldest phenomena they know are their grandparents. Selendia's lesson plans help to convey the message of "millions" and "billions" of years.