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February 26, 2007
Singer - Unstoppable Global Warming
Unstoppable Global Warming Every 1500 Years by S. Fred Singer and Dennis T. Avery, copyright 2007, 260 pages, Rowman & Littlefield Publishers, Inc.
The authors are published scholars specializing in climate science and the environment. The book is intended for the lay reader but extensive footnotes (500 give or take) make further study possible for those who are interested.
The basic message of the book is that, first, the scientific debate is not over. There are serious problems with the theory of global warming and in addition there are plausible alternate theories about climate change. Second, the predictions of disaster offered by global warming proponents and the media are very unlikely.
I'll touch on a few of the ideas in the book to give a sense of its points. Global warming advocates rely on three things. (1) An observation that the earth has been warming in recent decades, as best we can tell from the data. (2) The idea that carbon dioxide is a "greenhouse" gas which can be expected to trap the heat from sunlight and cause temperature build-up. (3) Computer modeling of climate change, which after starting with a number of assumptions, predicts heat build-up. Once these three yield a conclusion of continued warming, people start speculating about disaster.
How much warming there has been is debatable. There is a "heat island" effect in which the weather is always warmer in areas of human concentration, and that's where the measurements mostly are taken. There's an effort to back out the heat island effect from the data, but they may still be overestimating heating by 40%.
There probably has been climate warming since about 1850, with occasional reversals for a decade or two. Global warming advocates say this is unique and is due to greenhouse gas emissions by industrialized society. The authors respond, look at history. We know a lot about climate in the past, from ice cores, seabed cores, lake bed cores, glacier cores, trees rings, written history, and various other sources. The earth has been warming and cooling periodically (cycling about every 1500 years) for a long time, independent of periods of glaciation. We're on schedule for a warming period which probably started around 1850, and it should continue to get a bit warmer. About 1000 AD in the Medieval Warm Period it was warmer than it is today. Continuation of an age old cycle of warming and cooling is nothing to get agitated about.
Global warming advocates either ignore history or reject it. For example they say the Medieval Warm Period was an isolated European event. But it is found in data from all around the world. Then there is the famous "Hockey Stick graph" which purports to show global temperature moving along more or less horizontally until we reach the industrial age, then temperature starts climbing. The graph covers the last thousand years and shows no warming and cooling cycle, but a dramatic temperature rise in recent years, accompanying the build-up of CO2.
The graph was generated by Dr. Michael Mann, then at the University of Massachusetts, and was much ballyhoed by the Clinton administration and the United Nations. Dr. Mann got a very nice promotion and his career prospered.
Dr. Mann's study was based to a large degree on tree rings as an indicator of temperature, a legitimate approach. The article was subject to peer review, which is where other scientists independently repeat the experiments or analyze the data. In this case the data was analyzed by two Canadian experts in statistical analysis. The data did not support the conclusions or the graph. There were "collation errors, unjustifiable truncation of extrapolation of source data, obsolete data, geographic location errors, incorrect calculation of principle components and other quality control defects." (see page 70)
That's not all. Data on the most recent temperatures was taken from a report which studied slow-growing Bristlecone pines high in the Sierra Nevada. Their thicker tree rings in recent years were taken as evidence of higher temperatures, the upturn portion of the hockey stick. (Other things being equal, trees grow more in warmer weather.) But the paper actually showed there was a different cause for the wider tree rings. The scientists who conducted the study demonstrated that the added growth was due to a higher level of CO2 in the atmosphere, not elevated temperatures. See "Detecting the Aerial Fertilization Effect of Atmospheric CO2 Enrichment in Tree Ring Chronologies" by Donald Graybill and Sherwood Idso.
One of the key documents Dr. Mann relied on expressly did not support his theory. The Hockey Stick graph is nonsense.
So much for climate history, how about the theory? We've all sat in cars in the sunshine with the windows rolled up. The greenhouse effect seems logical. But a few problems arise when you extrapolate from your car to the earth's atmosphere. The gases that could produce a greenhouse effect are water vapor (60% of the potential total effect), CO2 (20%), and other gases (20%) including the highly publicized barnyard animal flatulence. Nobody knows how water vapor is going to behave. Global warming should produce more water vapor, so it's terribly important. Low level clouds cool the earth. High level cirrus clouds warm the earth. Without a sound understanding of how water vapor will behave, any prediction based on a theoretical greenhouse effect is conjecture.
Computers? The book has an extensive discussion. The computer models fail to account for recent heating and cooling periods. Generally even very minor errors in assumptions become very large when computations are run over and over and over again. The book doesn't say this, but if computer modeling of climate can be done, why can't they give us an accurate weather forecast for four weeks from today?
What does cause climate change? One major factor is the sun. Its rays warm the earth. There's variation in how much sunshine we get. Part of that is due to the motion of the earth; our elliptical orbit is not constant. Sometimes it's "flatter" and sometimes it's "rounder". That can affect how far away we are from the sun. Also the earth's axis wobbles, which can affect which parts of the earth get more or less sunlight, perhaps intensifying the seasons. Also the sun varies its output. Times of high sunspot activity are associated with warmer weather.
In addition to the amount of sunshine hitting us, there are two other effects from the sun which may cause even greater variation in earth temperature. Strong output from the sun shields the earth more from cosmic rays - radiation from the rest of the galaxy. Cosmic rays ionize molecules in the atmosphere, and the ionized particles form tiny water drops, making clouds. Weaker sun, more cosmic rays, more clouds, cooler weather. In addition strong sunlight creates more ozone molecules in the upper atmosphere, which then absorb more ultra-violet radiation, warming the atmosphere. The cosmic ray and ozone effects can be several times stronger than effects directly from additional sunshine.
It is possible for scientists to reconstruct the history of the strrengh of the sun's activity, and it correlates well with the temperature and climate history data from other sources.
Disasters? There are chapters on sea level rise, species extinction, famine and drought, abrupt global cooling, and the threat of millions of human deaths. Analysis of each supposed threat shows there is no basis for panic. In fact the moderate global warming we can expect will probably be beneficial to humans and other life on earth.
If you care about the topic, read the book. Otherwise, don't worry. My view of global warming is it's analogous to Y2K; a little bit of science, some legitimate concern, tons of hype, and a vast amount of self-serving talk.
Posted by rob at February 26, 2007 04:14 PM
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Posted by: Anonymous at February 26, 2007 04:14 PM