I did not intend to start 2013 with a column about global warming. However, when I was confronted with the above quote from the new North Carolina Secretary of the Department of Environment and Natural Resources (DENR), John Skvarla, in the December 26 edition of the News and Observer, I had no choice. The quote from Mr. Skvarla inspires two important questions: “What does Mr. Skvarla actually mean when he says this?” and “Why don’t our news reporters ask better follow-up questions when science topics are being discussed?
If Mr. Skvarla thinks that global warming is an “open question,” then he must harbor some skepticism regarding at least one of the three elements of the Green House Effect:
- carbon dioxide absorbs infrared radiation from solar energy reflected from the earth’s surface;
- carbon dioxide concentration in the atmosphere has risen dramatically due to human use of fossil fuels; and/or that
- global average temperatures have risen by 0.9 oC since 1880 in conjunction with the rise in carbon dioxide concentration.
Let’s examine these one at a time.
The graph below is a bit technical, but the message is important, so please bear with me.
The two black humps show the wavelengths of solar energy which hit the earth and of those which are reflected back. The green line shows the infrared (IR) absorbance spectrum of carbon dioxide. The peaks in the spectrum correspond to the wavelengths of energy that a carbon dioxide molecule will absorb. The flat sections of the spectrum correspond to the wavelengths of energy which will pass right by carbon dioxide without any interaction. When a molecule is subjected to IR radiation that it can absorb, it heats up.
Note how the largest peak in the carbon dioxide IR spectrum aligns almost perfectly with the wavelength range of solar energy being reflected by the earth. This alignment of wavelengths is the scientific basics of the Green House Effect. In fact, without carbon dioxide’s ability to absorb reflected solar energy, the global average temperature of the earth would be around 0 oC rather than the current level of approximately 14 oC.
Surely Mr. Skvarla does not harbor doubts about the infrared absorbance spectrum of carbon dioxide.
The next graph shows the carbon dioxide concentration in the atmosphere over the last 400,000 years.
Two conclusions are clear from the data: carbon dioxide concentration in the atmosphere has risen dramatically since the start of the industrial age in the mid 1800s, and our current level of 390 parts per million is significantly higher than at any time during the past 400,000 years. For reference, 400,000 years ago was approximately the time at which primitive plants first migrated from water to land. This staggering rise in atmospheric carbon dioxide concentration since the 1800s is a direct result of burning fossil fuels (petroleum, natural gas, and coal).
Surely Mr. Skvarla does not doubt that burning fossil fuels has added carbon dioxide to the atmosphere.
This third graph shows the rise in atmospheric carbon dioxide concentration since 1880 and the corresponding 0.9 oC increase in global average temperatures.
Does Mr. Skvarla doubt the temperature data or does he think that the correlation with carbon dioxide concentration is not correct?
When our DENR Secretary makes science-related statements, follow-up questions from the media are needed to help the public better understand Mr. Skvarla’s positions. In my experience, as soon as the subject matter approaches a scientific issue, the quantity and quality of follow-up questions from the media drop precipitously. This is a shame and it is also unnecessary. You do not need to be a trained scientist to ask Mr. Skvarla the obvious follow-up question, “Which aspect(s) of the science of global warming to you consider to be ‘open questions’ ?”
Mr. Skvarla might give an answer which addresses the types of science issues I reviewed above. He might dodge the question entirely. He might give an answer I haven’t anticipated. Any of these answers would be enlightening and provide insight into the person we are entrusting to safeguard our state’s environmental resources. But if no one asks the question, we’ll never know the answer.
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