Letter: Look at global warming in a more scientific way (Printed Dec. 7, 2007)
Editor:
There have been a number of recent letters to the Post concerning global warming. Two letters questioned whether it was actually occurring or not and the third countered those by presenting statistical evidence to support the fact that it actually is occurring. Unfortunately, this back-and-forth argument will continue as long as climate scientists insist on presenting their evidence in the form of statistical analyses whose percent errors often exceed the range of the initial data to begin with.
While the statistical data is not clear on the effects of global warming, the mechanism that causes global warming is well understood and even experimentally verifiable. Climate scientists should take more time to explain this effect to the public since it requires nothing more than a little high school chemistry to understand, rather than presenting the results of “massaging” vast piles of data.
For those who are interested, the mechanism is as follows. Most of the sun’s energy is in the form of visible light. The earth’s atmosphere (including carbon dioxide) allows most of this energy to pass right on through. It is then absorbed by the earth and everything on the earth (us, animals, plants, buildings, rocks, etc.) to varying degrees. Some of that energy is converted to other forms (e.g. photosynthesis) and the rest is re-radiated back up into the atmosphere in the form of infrared energy. This, however, does not pass through unimpeded. Water vapor and carbon dioxide absorb this energy. It then is re-radiated (still in infrared form), but gets re-radiated in every direction which means about half of it gets sent back down toward the earth. This is somewhat misleadingly called the “greenhouse effect.” In a real greenhouse, hot air is trapped whereas in the atmosphere it is energy that is being re-radiated back down toward earth’s surface.
This effect is important to an extent because it is what keeps the earth from losing too much heat at night. However, there is a delicate balance. For most of earth’s history any additional carbon dioxide added to the atmosphere (by living organism, volcanic eruptions, etc.) was removed by water vapor (in the form of rain) since carbon dioxide dissolves in water (that’s how you make a carbonated beverage). But since the beginning of the industrial revolution, this natural cycle can’t keep up with the added carbon dioxide. As such, more and more infrared energy is being absorbed and then re-emitted.
Think of the atmosphere as the Maine Turnpike, people as carbon dioxide, and vehicles as infrared energy. Increasing traffic on the turnpike (more people equals more vehicles) led the state to add a lane on the first 50 miles of the turnpike in order to ease congestion. Unfortunately we can’t add a proverbial “lane” to the atmosphere. That’s what global warming is. It is not controversial in the science community since it is simply very well understood physics and chemistry. How fast it is occurring and what effects a warming globe will have may be unclear, but the fact that it is happening is not.
Ian T. Durham, Ph.D.
Kennebunk
There have been a number of recent letters to the Post concerning global warming. Two letters questioned whether it was actually occurring or not and the third countered those by presenting statistical evidence to support the fact that it actually is occurring. Unfortunately, this back-and-forth argument will continue as long as climate scientists insist on presenting their evidence in the form of statistical analyses whose percent errors often exceed the range of the initial data to begin with.
While the statistical data is not clear on the effects of global warming, the mechanism that causes global warming is well understood and even experimentally verifiable. Climate scientists should take more time to explain this effect to the public since it requires nothing more than a little high school chemistry to understand, rather than presenting the results of “massaging” vast piles of data.
For those who are interested, the mechanism is as follows. Most of the sun’s energy is in the form of visible light. The earth’s atmosphere (including carbon dioxide) allows most of this energy to pass right on through. It is then absorbed by the earth and everything on the earth (us, animals, plants, buildings, rocks, etc.) to varying degrees. Some of that energy is converted to other forms (e.g. photosynthesis) and the rest is re-radiated back up into the atmosphere in the form of infrared energy. This, however, does not pass through unimpeded. Water vapor and carbon dioxide absorb this energy. It then is re-radiated (still in infrared form), but gets re-radiated in every direction which means about half of it gets sent back down toward the earth. This is somewhat misleadingly called the “greenhouse effect.” In a real greenhouse, hot air is trapped whereas in the atmosphere it is energy that is being re-radiated back down toward earth’s surface.
This effect is important to an extent because it is what keeps the earth from losing too much heat at night. However, there is a delicate balance. For most of earth’s history any additional carbon dioxide added to the atmosphere (by living organism, volcanic eruptions, etc.) was removed by water vapor (in the form of rain) since carbon dioxide dissolves in water (that’s how you make a carbonated beverage). But since the beginning of the industrial revolution, this natural cycle can’t keep up with the added carbon dioxide. As such, more and more infrared energy is being absorbed and then re-emitted.
Think of the atmosphere as the Maine Turnpike, people as carbon dioxide, and vehicles as infrared energy. Increasing traffic on the turnpike (more people equals more vehicles) led the state to add a lane on the first 50 miles of the turnpike in order to ease congestion. Unfortunately we can’t add a proverbial “lane” to the atmosphere. That’s what global warming is. It is not controversial in the science community since it is simply very well understood physics and chemistry. How fast it is occurring and what effects a warming globe will have may be unclear, but the fact that it is happening is not.
Ian T. Durham, Ph.D.
Kennebunk
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