Dr Roy Spencer spells out his position

Posted on timeJuly 28th, 2007 by userPali Gap


Against the view that “the debate is over” and that there is a “scientific consensus” we have here a nice PDF pamphlet from a research scientist with some claim to “authority” (not that that matters as regards the truth of the matter, but it is evidence for the falsification of the glib claims of consensus).

Dr. Roy W. Spencer is a principal research scientist for the University of Alabama in Huntsville and the U.S. Science Team Leader for the Advanced Microwave Scanning Radiometer (AMSR-E) on NASA’s Aqua satellite. In the past, he has served as Senior Scientist for Climate Studies at NASA’s Marshall Space Flight Center in Huntsville, Alabama. Dr. Spencer is the recipient of NASA’s Medal for Exceptional Scientific Achievement and the American Meteorological Society’s Special Award for his satellite-based temperature monitoring work. He is the author of numerous scientific articles. Dr. Spencer received his Ph.D. in Meteorology from the University of Wisconsin in 1981.

Dr Spencer argues:

  • There has been warming since the 1800’s (about 1deg C)
  • He agrees that CO2 is a greenhouse gas, and that industrialization has seen significant increases in CO2 emissions
  • However warming before 1940 is an anomaly as most CO2 emissions occurred after 1940. Instead this warming is best explained as a natural rebound from the unusually cool period before the 1800’s (the “Little Ice Age”)
  • Evidence from ice cores shows that temperature rises precede CO2 increases, not the other way around
  • Those who theorise about CO2’s role posit that mankind’s activities have resulted in a one watt per metre2 change in the energy-in/energy-out planetary balance. However there is no empirical test for this claim as yet (as it is too small to measure)
  • The greenhouse effect of CO2 is nowhere near as significant as the effect of water vapour (or methane for that matter). Weather systems drive the greenhouse effect far more than CO2:

“I believe it is because these weather systems act as a natural thermostat, adjusting precipitation, cloud, and water vapor amounts in response to solar heating in such a way that a stable average temperature is maintained”

  • So to inflate the importance of CO2, warming-mongers need to wheel out the mechanism of “positive feedback” to get their their doom-saying going. The usual recourse is to the idea that increasing surface temperatures will cause increased water evaporation, but Dr Spencer does not accept that surface evaporation is the prime, or even a key driver of water vapour levels.
  • The precipitation systems that do control water vapour levels are as yet poorly understood and modeled. However Dr Spencer believes that there is probably a negative feedback: warmer precipitation systems are more efficient at removing water vapor than cooler precipitation systems.
  • If water vapour feedbacks are controversial, the feedback effect of clouds is even more so. It is to be expected that an increase in high clouds (cirrus) would have a warming effect; an increase in low level clouds should have a cooling effect. Dr Spencer seems to be sympathetic to the cosmic ray conjecture (Svensmark et al.). The sun he says “is more active now than it has been for many centuries“. The result of this may have been reduced low level cloudiness (a strong sun reduces cosmic rays, which in turn are thought to have a role in “seeding” low level clouds).

To sum up:

“I believe that the (computer) models do not correctly handle precipitation processes, and it is those processes which control most of the Earth’s natural greenhouse effect.”

Dr Spencer’s PDF pamphlet is here “Global Warming: What You Haven’t Been Told

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