"Increasing vehicle and manufacturing emissions are causing an increase in the earth's surface temperature and to continue along our current path will result in catastrophic consequences."
That is the global warming argument former Vice President Al Gore presented so compellingly in his Academy Award-winning documentary, "An Inconvenient Truth." A lot has been said and written about the critically important issue of human-caused (anthropogenic) global warming, or AGW. To understand what is really happening and why, and what might happen in the future, let's start by separating truth from hyperbole.
First, everyone should understand that the issue of global warming -- or "climate change," as many now call it -- has little or nothing to do with the traditional notion of "air pollution," though environmental alarmists, politicians and media love to lump the two together. The reason global warming is unrelated to clean air is simple: CO2, the alleged culprit, is neither "dirt" nor a pollutant.
Take a deep breath. Now, exhale. Much of what just came out of your mouth is carbon dioxide, or CO2. All air-breathing creatures take in air, and their lungs separate the oxygen from it. What emerges from the other end of this life-sustaining process is CO2, which is exhaled with every breath every moment of their lives. The other element of this brilliantly designed system is plant life, which absorb CO2 and "exhale" oxygen. This is why deforestation, which reduces the number of CO2-breathing plants, accelerates the increase of atmospheric CO2.
The U.S. Supreme Court confused the issue in 2007 by ruling that CO2 is a "pollutant." Why? So they could compel the Environmental Protection Agency (EPA) to regulate it. A majority of Supreme Court justices, like a substantial percentage of Americans as a whole, believe that increasing levels of CO2 in the Earth's atmosphere have warmed the planet in recent years and will continue to do so, with potentially dire consequences, if allowed to continue growing unabated.
Carbon dioxide -- not to be confused with potentially poisonous carbon monoxide (CO) -- is colorless, odorless and absolutely harmless. It is the bubbly gas in our beer and carbonated soft drinks. But it is also emitted when carbon fuels are burned, and it composes roughly four percent of the "greenhouse" gases that help regulate the temperature of our planet.
Atmospheric greenhouses gases effectively trap heat by absorbing some of what is reflected by the Earth's surface and re-radiating some of that back downward. This natural process is essential for life on Earth. Without it, scientists say, the surface temperature would average about zero degrees Fahrenheit. Water vapor is most of the other 96 percent of these life-giving gases, but the CO2 component has been increasing (due, it is theorized by some, to combustion of fossil fuels, fast-growing human and animal populations and deforestation) since the industrial revolution. From a pre-industrial concentration of 280 parts per million (ppm), atmospheric CO2 has grown to 380 ppm today, and the current 1.9 ppm-per-year rate of increase predicts nearly 400 ppm in 10 years and 550 by the end of this century.
That is still a tiny amount -- 380 ppm equates to 0.038 percent, or 38 molecules of CO2 out of 100,000 of everything else -- but many scientists contend that even that concentration is so far above the estimated range of 180 to 300 ppm over the past 650,000 years and, very importantly, that the resulting increase in greenhouse gases has caused a warming trend over the last century. Further, they warn, that warming trend could be catastrophic. According to data accumulated by the National Oceanic and Atmospheric Administration's National Climatic Data Center (NCDC), global surface temperatures have increased about 0.74 degrees C (roughly 1.3 degrees F) since the late 19th century, and the linear trend of 0.13 degrees C per decade over the past 50 years is nearly twice that for the past 100 years. This suggests that things are getting hotter faster than ever before.
Where the debate really begins and scientists split into warring camps is over the issue of cause and effect. The fact that both atmospheric CO2 and global temperatures have increased in the past 150 years may or may not mean that one phenomenon is causing the other. Scientists believing the theory that the two are linked often base their conclusions on complex computer-based "climate models" that attempt to understand the global climate's behavior and the interaction of its components, then predict its future.
Projecting the undeniable temperature trend of the relatively recent past into the distant future would suggest some scary long-term scenarios. Among them are melting ice caps and glaciers, rising sea levels and potentially disastrous heat waves and droughts, especially in warm tropical regions. The NCDC says global mean sea levels have risen an average 1.7 mm (0.07 in.) per year over the past century and could rise another 0.18-0.59 meters (0.6-1.9 ft.) over the next 100 years, "depending on which greenhouse gas increase scenario is used."
A Special Report on Emission Scenarios issued by The U.N.'s Intergovernmental Panel on Climate Change (IPCC), which is made up of scientists and environmental activists from around the world, predicts a range of possible future greenhouse gas concentrations based on, among many other factors, population growth, economic growth and energy efficiency. "This leads a wide range of possible forcing scenarios [possible causes]," says NCDC, "and consequently a wide range of possible future climates. According to the range of possible forcing scenarios, and taking into account uncertainty in climate model performance, IPCC projects a best estimate of global temperature increase of 1.8 - 4.0 degrees C, with a possible range of 1.1 - 6.4 degrees C by 2100, depending on which emissions scenario is used.
That translates to as little as two degrees or (worst case) as much as 11.5 degrees F over the next 92 years, depending on which climate model is used and what CO2-limiting laws can be passed and enforced by nations around the world. The challenge with IPCC's mission of forcing global CO2 reductions, however, is that population and economic growth, nearly by definition, consume ever more energy and produce more and more CO2. What nation will voluntarily cut its economic activity or attempt to reduce its population?
While the AGW debate is far from over, here are several salient facts:
• Global warming is unrelated to air pollution because CO2 is not a pollutant
• CO2 is not carbon monoxide (CO); it is produced naturally, exhaled by air-breathing animals, emitted when carbon fuels are burned and is the fizz in carbonated drinks
• Greenhouses gases trap heat and by re-radiating some of it back downward
• CO2 comprises roughly four percent of total "greenhouse" gases, but its increased concentration in the atmosphere may be contributing to a warming of the globe
• Atmospheric CO2 has increased from about 280 to 380 parts per million (ppm) since the industrial revolution, and the current rate of increase is 1.9 ppm per year
• 380 ppm is just 0.038 percent or 38 molecules out of 100,000
• Deforestation accelerates the increase of atmospheric CO2
• If the Earth warms unabated or in an accelerating fashion the results might include melting ice caps and glaciers, rising sea levels and potentially catastrophic heat waves and droughts
• Sea levels have risen 1.7 mm (0.07 in.) per year over the past 100 years and could rise another 0.18 - 0.59 meters (0.6 - 1.9 ft.) over the next century if currently used models prove accurate
• The IPCC predicts a global temperature increase of between 2.0 and 11.5 degrees F over the next century, depending which climate model and emissions scenario are used
Since continued population and economic growth will inevitably consume more energy, it appears that the only realistic way to significantly decrease man-made CO2 that might be contributing to a global warming trend will be to develop safe and affordable non-carbon energy sources that will, over time, enable the world's populations to consume the massive and fast-increasing amounts of energy they will need to survive and thrive without emitting proportionally growing volumes of greenhouses gases, mainly carbon dioxide.
That's half the story. Here's the other:
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