November 14, 2006 > Global Warming: Myth or Menace?
Global Warming: Myth or Menace?
Scientists, politicians, and environmentalists have been telling us the earth is getting warmer. Many have warned that if this trend continues, dire consequences await. Is global warming a reality? Is it due to human activity? Will the result be cataclysmic?
The answers to these questions lie in the realm of science. The TechKnow Guy is uneasy when politicians, activists, and the media substitute sensationalism and rhetoric for scientific research. Let’s see if we can separate reality from hyperbole.
There is no longer any question that we live on a warming planet. The years 1998 and 2005 were the two warmest since accurate records have been kept (some 120 years). Moreover, nine of the ten warmest years on record have occurred since 1995. The average global temperature has increased by about 1.3 ºF in the last 100 years. Researchers have determined that the earth has not been as warm as it is now for at least 1000 years.
Much of this temperature increase has occurred since 1990. The fact that the planet is heating up at an increasing rate is of particular concern. There have been natural temperature variations throughout the earth’s history, but after intense scientific debate over the last 15 years, there is now a strong consensus that much, though perhaps not all, of this recent temperature increase is the direct or indirect result of human activity.
What human activities cause global warming? When agriculture was developed thousands of years ago, it started a population explosion, and large areas of forest were cleared to provide sufficient farmland. This deforestation continues today in many parts of the world, reducing the planet’s ability to cool itself.
The industrial revolution, beginning in the late 18th century, resulted in a tremendous increase in the burning of fossil fuels, primarily coal. In our lifetimes, the massive consumption of oil and natural gas to support modern industrial manufacturing, mining, transportation, power generation, heating, etc. has expelled huge quantities of greenhouse gases (carbon dioxide, methane, nitrous oxide, and CFCs) into the atmosphere.
These gases, most notably carbon dioxide, cause the greenhouse effect by acting as a blanket over the earth. The relatively short wavelength light from the sun easily penetrates these gases to warm the earth. The earth in turn attempts to cool itself by radiating longer wavelength infrared radiation, some of which the greenhouse gases absorb or reflect rather than transmit into space.
Global warming becomes a problem when it causes climate change. Though a degree or two of temperature increase seems tiny, it has been sufficient to create some rather startling changes. For example, melting ice caps, a rising sea level, shrinking glaciers and ice fields, and impacts on plant and animal habitats are well documented. It is also plausible that global warming has contributed to heat waves, flooding, droughts, increased intensity of tropical storms, and the spread of mosquito-borne diseases, though more research is required to confirm these effects.
The amount of additional temperature increase we can expect in the future is difficult to estimate, as is the effect of that increase on the planet. It seems certain that global warming will continue in the short term, and probably at an accelerating pace. The remaining natural reservoirs of carbon dioxide, such as peat bogs, appear to have absorbed all they can handle, and may be beginning to emit those gases back into the atmosphere.
In addition, loss of ice fields is a particularly vexing problem, as it creates a vicious cycle. Where ice melts, it is replaced by land or water, both of which are less reflective than ice. Thus, more of the sun’s energy is absorbed by the earth, raising its temperature, resulting in more ice melt, and perpetuating the cycle.
Many analytical models estimate, at the current rate of greenhouse gas production, an additional increase of 3-10 ºF during this century. No one can know exactly what impacts such a temperature increase would have on the earth, but even a few degrees would be very dramatic from a human perspective. Hundreds of millions of people would be displaced by rising sea levels and weather patterns would be profoundly altered. Far more serious consequences are very likely.
What can be done to avert calamity? Greenhouse gases can remain in the atmosphere for a very long time, in some cases more than 100 years, so any changes we make now will probably merely reduce the rate of temperature increase, not stop it. This is a good reason to start now in controlling the emission of greenhouse gases.
We should also realize that this is a long-term, global problem, and will not be successfully addressed by individual governments acting alone or by short-term policy decisions. Similarly, doomsayers and grandstanders do not contribute to the solution; the sky will not fall tomorrow. The global community needs to recognize and understand the problem, and agree to approach a solution together. Fortunately, this has begun to happen in recent years.
In the meantime, each of us can help by reducing our energy consumption, driving less, using alternative fuels when possible, and supporting environmentally-friendly companies. We could also encourage our politicians to tone down the rhetoric and get to work on meaningful legislation.