Introduction
Global warming has been a subject of much debate for the past few decades and hardly anyone today can deny the reality of it. Most scientists agree that its origins are human induced but, not surprisingly industrialists and merchants in different fields deny the possibility of anthropogenic influence on the atmosphere's chemical structure, much less the conditions of climate and its effects on the world's biota. These people are inclined to argue that the climate has always changed on planet Earth. Other people, among whom I count myself, admit that although this is so, the episode that we are beginning to encounter had its origins, not with natural processes, but by human's zeal to resolve our problems with little regard to the consequences, and thus we have polluted the stratosphere in a most dangerous way.
My goal in writing this unit is for my fifth grade students to learn about the history of the Earth and the shifts that plants and animals have had to make to survive and reproduce. I want them to understand that humans are part of the natural world and that our species too, has had to make adjustments to some of the changes. Those changes have helped us improve our cultural development while others have caused the downfall of cultural groups of advanced civilizations.
Another purpose in writing this unit is to impress upon my students the interrelatedness of species with each other as well as with the abiotic factors in their ecosystems. Therefore we will look at the effects of global warming on different aspects of our lives: water availability, storm events, land usage, agriculture, and health.
Although the projections of the International Panel on Climate Change (IPCC) are regarding countries around the world I will analyze the coastal plains on the Gulf of Mexico for evidence of global warming effects already taking place. I will focus on the metropolitan area of Houston toward Galveston bay because it is where my students and I live. Furthermore, the eastern portion of the Houston Metropolitan area is where a large portion of the pollutants are released into the air causing many illnesses such as cancer, asthma, and other bronchial and pulmonary diseases.
The cities in the metropolitan area were built on coastal wetlands so they are at sea level and the aquifers that underlie them and part of the Gulf itself provide fresh water for agriculture as well as urban needs. But in the past those aquifers have been over exploited permitting not only salinization of the water but also causing a constant problem of land subsidence. Records show that between 1900 and 1990 Houston has subsided 9 feet. Subsidence and rising water levels do not presage a long future for this city. What is more, the increasing number of tropical storms, electrical storms, hurricanes and tornadoes that hit the region throughout the year cause numerous disruptions to the city's economic progress. Often the storms result in flooding that paralyzes transportation and perturb the accumulated toxic materials that lay on the ground from the industrial pollutants. The usual outcome of these episodes is an increase in disease and other health related issues.
Always a problem in the region; mosquitoes have also increased their numbers along with the diseases that they have habitually carried: malaria, yellow fever and dengue. This last one had always been confined to tropical regions but global warming is expanding those regions well into the coastal regions of Texas. Malaria has also found its way back to Houston and the United States where it had been eradicated in the mid forties. The poor, the very young and the aged are the most likely victims of these diseases even in cities like Houston because their families cannot always afford to air condition their houses. They spend a great deal of time out of doors. Unless they have ample access to fresh drinking water dehydration is another health issue that can result in diarrhea and often, death1.
I have intentions of integrating the concept of climate change and its effects, both present and past to my students' social studies, science and reading curricula. The social studies lessons will focus on social and cultural shifts in response to climate change as the one experienced from ~ AD 540 - 800 in which temperatures dropped as the result of a volcanic eruption; followed by a gentle warming period that lasted about five hundred years. The period that followed became increasingly colder as it progressed into the 1850s. During that last cooling episode humans made incredible strides to make their environments more habitable, inadvertently sowing the seeds that upon maturation are threatening the ocean's and earth's biodiversity along with the geomorphology of the earth itself. As I teach these aspects of human adaptations I would like my students to become aware that not all areas of the globe are affected identically during the episodes of climatic change, so that if one region is being subjected to heavy flooding events another might be going through quite the opposite: droughts and the subsequent aridity. In some areas the vegetation will expand its boundaries while in others fires and droughts will render a region barren. Any of these conditions will determine the growth of animal species and populations or their disappearance and extinction.
Understanding of these conditions will probably provide me with a logical scenario by which to explain the dynamics behind the European explorations and their meeting with the Amerindians. By discussing the past, drawing parallels with it and looking at the evidence of the warming trend that we are facing the students will be asked to forward ideas about cultural and social adaptations that the people in our area will be required to make in order to guarantee a future. Implicit in these projections will be their understanding of the situation not only from the social stance but, from the scientific one.
In brief, my goals in teaching these concepts are to create in my students an awareness of the integral part that humans have on their environment, the need to exercise forethought before physically, chemically or biologically altering the planet's ecosystems and to search for ways to respond to the realities threatening our civilization.
Comments: