This summer treated us to the films "Too Hot Not To Handle" and Al Gore's "An Inconvenient Truth," as well as news that the Supreme Court will decide whether carbon dioxide (CO2) should be considered a pollutant under the Clean Air Act.The big problem with this piece is a very critical omission. The last paragraph admits that CO2 elevation causes global warming, but says that its levels have "fluctuated enormously" over the history of the earth. But it fails to tell us what the record of CO2 fluctuation shows and where we stand today in comparison to the existing past record, leaving the reader with the false impression that the current levels are within normal historical fluctuations. CO2 levels today are much higher than they have been in the last 400,000 years (which I believe has now been extended to 600,000 years), as documented by CO2 levels in Antarctic ice cores.
Reinforcing the idea that CO2 is a pollutant, Gore and others often speak of "CO2 pollution." Before you train yourself to add the "p" word to your vocabulary, consider that CO2 comes from the Earth itself and its levels have fluctuated greatly throughout history.
At one point, atmospheric CO2 levels dropped drastically and came perilously close to suffocating the global ecosystem. If someone is concerned about dangerous levels of atmospheric CO2, too low is far more dangerous than too high.
Experiments show that when CO2 levels increase, plants grow faster and bigger. In order to make CO2 more sinister, claims are made that ragweed and poison ivy will grow more vigorously in the future, and indeed they will. But so will every tree in the forest.
There is no doubt that CO2 is a greenhouse gas that when elevated will act to warm the Earth. However, its levels have fluctuated enormously over the history of the Earth, and the ecosystems of the planet have adjusted to cope with these variations. The Supreme Court ruling will be interesting, but Mother Earth has clearly ruled that CO2 is not a pollutant.
Dr. Robert C. Balling Jr. is a Goldwater Institute Senior Fellow and is a professor in the climatology program at Arizona State University, specializing in climate change and the greenhouse effect. A longer version of this article originally appeared on TCSDaily.com.
To quote Steve Albers at NOAA:
The reason I would be most concerned is not what has happened so far, but what can very possibly happen if we stay on the present course. Carbon dioxide (CO2) mainly from fossil fuel burning is being released into the atmosphere faster than natural processes can remove it, thus increasing atmospheric concentrations. The rate of rise in CO2 concentration has been increasing as well, from about 1.3 parts per million per year several decades ago to about 2.2 ppm/yr in 2005. The natural background is about 280ppm and current CO2 concentrations are about 380ppm. A linear extrapolation of the 2005 trend would yield a doubling of CO2 over natural values by around 2080. It is often suggested that short of that, values of just 450ppm would represent a threshold of unacceptable changes in the environment. These values are potentially just a few decades away.
If we wait until things get obviously worse before we take action it could be too late for reasonably quick action to restore our familiar climate. One reason is because the ocean reservior of CO2 might be filling up and it would then take hundreds of years or more to reverse the CO2 back to its "natural" level to undo the warming effect. Another aspect of the carbon cycle is that even if the global emission rate is held constant, the CO2 concentration in the atmosphere would continue to rise for quite some time (e.g. one or more centuries) and reach levels several times what it is at present. Alternatively, to hold the CO2 concentration at current levels, the emission rate would have to be cut by roughly one-half (without considering the effect of the ocean reservoirs filling up). To hold the currently elevated temperature constant the emission rate would need about a two-thirds cut. Even if we magically turned off all emissions at once, it would probably take 100-300 years for CO2 levels to come down close to the natural background levels. The corresponding "half-life" would be something on the order of 50 years, subject to changes in the various CO2 sinks.
Since carbon emissions are continuing to grow (primarily because the major method of electricity production around the globe is burning coal), the levels are continuing to rise (graphs are from Wikipedia).
For whatever faults one might find in Al Gore's presentation in "An Inconvenient Truth," at least he presents the data to support what he says--and I recommend that everyone see that movie.