Δ KNOWLEDGEBASE
« Responding to Climate Change
Excerpt from In Search of Environmental Excellence:
Moving Beyond Blame
by Bruce Piasecki and Peter Asmus
CHAPTER 3
A Global Greenhouse: Framing the Debate
Page 3 of 14
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These groups all cautioned that such increases in temperature would alter the global availability of water, which could cause widespread disruptions along coastal shorelines and in international agricultural yields. The Environmental Protection Agency further cautions that if present trends continue, the climate may change as fast in the next century as it has over the eighteen thousand years since the last ice age. Here in the United States, global warming could drastically change lives, transforming lush fields of grain into deserts while causing widespread flooding elsewhere. America, and the rest of the world, may be forced by these changes to spawn a revolution in energy generation and consumption, as well as in product design and manufacturing.
The global-warming crisis underscores the delicate balance that exists between industrial growth and environmental health. In order for society to be sustained, significant reductions in emissions of greenhouse gases — primarily carbon dioxide (CO2) but also chlorofluorocarbons (CFCs) and methane — must occur. The least disruptive way to do this is through greater energy efficiency.
If we don't respond, what might tomorrow feel like? The answer lies in any greenhouse when all of its windows and vents are shut. Transparent windows allow the sun's rays to enter and warm the surroundings, but do not allow the hot air to escape. (Heat is a form of infrared radiation, invisible but felt by the skin. The same window that lets visible light enter, also prevents infrared radiation from escaping. Thus, the temperature rises.) The earth's atmosphere is similar to that of a greenhouse. The atmosphere allows visible light to enter, but blocks infrared rays. Overall, this is beneficial: gases and vapors surround the earth like a blanket, maintaining a warm, inviting atmosphere in which life can flourish. This blanket separates the earth from its cold, empty surroundings. Without a greenhouse blanket, the surface of the earth would be 70° F colder, and the oceans would freeze.
The new problem is "runaway greenhouse," a kind of smothering in our own blanket. A trend toward warming on a worldwide basis cannot easily be halted once it has started. To reverse this is as difficult as warming an ocean, or changing a season. We can only slow the trend down, and hope that the earth's plants and animals adapt to such temperature changes on a grand but gradual basis. This, without a doubt, will demand massive changes in the daily life of humankind.
War Without Borders
In Shakespeare's Macbeth, the witches claim that Macbeth's ambitions and pride will continue to rule until the forests move. Macbeth's downfall occurs when an approaching army cuts down the trees of a nearby forest and, using them as camouflage, moves the forest closer and closer to Macbeth's castle. They take the arrogant Macbeth by surprise when they emerge to strike from close range.
In a sense, the modern industrial world has been reliving Macbeth's tragic blindness. Forests are moving. A recent EPA report on global warming shows how this accelerated relocation of resources does not respect man-made political boundaries or ambitions.
After the last ice age, oak trees migrated northward from the southeastern United States as glaciers receded. Temperatures rose slowly enough that forests could adapt to climate changes (forests in these regions have historically moved only sixty miles in a century). The EPA warns, however, that hemlock and sugar maple ranges could move as much as four hundred miles north by the year 2050, most likely causing these classic trees to be pushed to near-extinction in the United States. The financial effects of this forecast are critical: many agricultural and forest products of America's fertile crescent — the Great Plains corridor — may move north to Canada, perhaps carrying billions of dollars in economic dislocation with it.
In California, the sea-level rise induced by high temperatures and melting glaciers would flood much of the Central Valley. Thousands of acres of the world's most prized farmland would be reduced to nonproductive shallow ponds and spillways. The increased salinity of the water would greatly reduce the populations of magnificent white egrets, trumpeter swans, and great blue herons, which depend on freshwater marshes. Regional harvests of crops such as sugar beets and corn, according to EPA models, could be reduced by twenty to forty percent.
