Climate of Doubt is new Frontline documentary that describes how public opinion in the United States has been manipulated to support inaction in the face of mounting evidence. Not surprisingly, the documentary has already drawn vociferous objections in online forums from those whose delusions it describes.
In the face of mounting evidence that humans have seriously altered the climate, all manner of strange theories are angrily espoused, either denying that the change is occurring or blaming the change on natural factors, or both.
The statistical evidence for human-induced climate change was -- until recently -- somewhat subtle, and the denial theories focus on the aspects of the evidence that are most complicated. The physics involved are quite simple, however, and I have never seen the basic physical processes explained away.
:How simple is the problem? Have a look at Frosty.
|Thanks to The Haunted Closet for the Frosty screen captures.|
Just like the glass on my south-facing porch, greenhouse glass is nearly transparent to visible light, but somewhat opaque to infrared (infra-red) energy. Most of what is emitted by the sun is visible; most of what is emitted by the earth (and objects at earth-like temperatures) is infrared.
Because of gases such as carbon dioxide, methane, and water vapor, the earth's atmosphere behaves in a similar fashion. Most incoming solar radiation (visible or shortwave) gets in, but some of the outgoing terrestrial radiation (infrared or longwave) gets trapped. This greenhouse effect occurs without humans, and we should be grateful for it!
What humans began to do about two hundred years ago, though, is to increase the concentrations of greenhouse gases in the atmosphere by taking the elements out of long-term storage and putting them in short-term storage -- for example converting coal that had accumulated over millions of years into gases that were released in dozens of years.
The effect is like thickening the glass on a greenhouse, or adding a blanket to a bed. It does not create heat, but it increases temperature in a specific location -- inside the greenhouse, under the covers, or in the case of the planet as a whole, within the troposphere. Those who decide that they do not "believe" in climate change are not able to explain this away, just as no other explanation can be offered for Frosty's puddleness.
For more information and resources, see my climate change web site, or see all climate change articles on this blog.