Forum: Physicist examines global warming

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The warming of our planet's surface and a possible correlation with rising carbon dioxide (CO2) levels has sparked considerable controversy about the origin of this warming (human-induced or an unpredictable act of nature?).

Whether it's the fact that 9 out of 10 of the warmest years on record occurred in this past decade or that 2006 (just the first half) was the warmest year for the United States, or that average global temperatures have been rising (by about 1 degree during the last century), evidence abounds of warming.

Despite many claims to the contrary, natural and human activity can alter the Earth's atmosphere and modify our environment. All the oxygen we breathe (21 percent of our atmosphere) was produced by life via photosynthesis. Smog is a more direct effect of human/industrially induced atmospheric alteration. Indeed, many past societal catastrophes such as the Dust Bowl mass migrations of the 1930s were likely caused by over-farming. With our great potential to create and learn, we also have great potential to cause our own self-destruction.

Our atmosphere is comparable to a rubber glove stretched over a bowling ball -- it is very thin. Due to our atmosphere, we don't suffer the extremes of temperature of Mercury and our moon. In the opposite extreme, since our atmosphere isn't as thick or dense as Venus, we don't suffer from oppressive heat (850 Kelvin) due to greenhouse warming that prevents water from condensing there.

Earth developed a very fortunate (for life) state of quasi-equilibrium. This allowed water to condense, removed most of the carbon dioxide from the air. And with liquid water as solvent, life evolved. However, human activity is probably altering this equilibrium by producing greenhouse gases (most notably carbon dioxide). These gases trap heat, warming Earth's surface and further release carbon dioxide (trapped in melting glaciers or warming oceans), further warming Earth's surface and creating a new equilibrium state in which all life may not survive.

Unlike water, which readily condenses into liquid and solid (ice/snow), carbon dioxide remains in the atmosphere roughly 100 years before its natural removal. Thus, any effort initiated today to reverse the warming trend will not bear fruit until decades later. Though carbon dioxide levels have cyclically varied from about 180 parts per million to 280 ppm over the last 650,000 years, we have never measured higher carbon dioxide concentrations during this period than now (370 ppm) -- roughly 27 percent higher than at any point in the Earth's "recent" history. Though many argue that greenhouse gas release via human activity pales by comparison with volcanoes and other geothermal releases, these events are very short term and have created problems for life in the past but were "rapidly" corrected.

Carbon dioxide produced by all life (not including humans) may be larger than that created by human activity. But without humans, it has been in equilibrium/balance for much time via the carbon cycle. Humans continue to add enormous additional quantities of carbon dioxide and other greenhouse gases and are also removing the ability of life to remove/sequester carbon dioxide (by e.g. decimating rain forests). This alters the Earth's natural homeostatic balance and it's possible we are only beginning to see the negative results.

To provide some perspective of the sheer quantity of CO2 introduced, consider that a gallon of gasoline releases about 20 pounds of CO2 (among other greenhouse gases) and given that our nation consumes more than 20 million barrels of oil every day, this implies about 9 billion tons of carbon dioxide are released into the atmosphere every day.

Whenever rapid change occurs, all life suffers as it struggles to adapt. The Earth's natural equilibrium can only take so many shocks before it irreversibly goes to a new state that may not support life, as in the rest of our solar system. We are conducting an experiment on our only home, Mother Earth, the results of which may not be known for some time and which may be catastrophic and irreversible.

Tragically, most of the voices from whom the public have heard discuss global warming (such as author James Creighton or politician Al Gore) are not scientists and have spun (or misunderstood) the science behind this phenomenon to suit their own political or dogmatic needs.

Scientists such as James Hanson who have been studying global warming for decades have been censored/muzzled by political bosses who have no little or no scientific training. Other scientists such as Peter Doran have had their data misinterpreted and misrepresented for political aims.

Unfortunately for humans, there is no politics in nature but absolute natural laws. We cannot go on pretending these laws of nature don't exist and can be violated without disastrous consequences. Whether it is warming, pollution, dwindling natural resources, pestilence and disease or overpopulation, the human race is on a collision course with reality and only science can avoid likely catastrophes ahead.

In that spirit, I encourage all members of the public and their leaders to first of all learn the science behind the phenomenon of global warming and engage scientists in the debate so we can all decide together on the future course of action to tackle and prepare for global warming for the survival of the human race.

MICHAEL PRAVICA

Assistant Professor of Physics

University of Nevada, Las Vegas

This essay was based upon a University of Nevada-Los Vegas University Forum talk given by Mr. Pravica last Spring and most recently given to the Las Vegas City Council to support their passage of a resolution on global warming.