The Gentlemen at RealClimate.ORG have decided that my article about climate sensitivity and similar articles by others are too dangerous because they show that every new molecule of CO2 causes smaller greenhouse effect than the previous molecule: the absorption rate gradually approaches saturation. Such a conclusion could diminish the holy power of the enhanced greenhouse effect and undermine the global efforts of scientists of good faith - and their friends, politicians of good faith, lawyers of good faith, singers of good faith, and publishers of good faith - to globally regulate the greenhouse effect.

They must be applauded for giving others the opportunity to study and discuss this question more carefully because the more people know, the more they will see why the hysteria is unjustifiable. So what do these eleven climate scientists think about the dependence of the strength of the greenhouse effect on the concentration? Well, they live in the state of scientific consensus which means, in this case, that none of them has any idea what the answer could be. So they invited an expert to clarify the situation.

Who is the expert? Well, it is a noted historian of science whose name is Spencer Weart, a guest blogger at Real Climate.
Ray Pierrehumbert has helped Weart to reduce excessive hyphenation. Weart is the author of a painful book that celebrates a greedy group of researchers who were dreaming about grants and who finally got them after they constructed the man-made global warming theory. Weart writes in such a way that the text is well-readable and looks insightful to superficial readers. If you read it carefully, however, you can see that Weart has no idea what he is talking about at the technical level.

Spencer Weart’s main goal is to deny or somewhat diminish the importance of the following two observations: (1) the greenhouse effect gets weaker as the absorption of the appropriate spectral lines gets saturated and (2) the overall greenhouse effect from several gases is smaller than a simple sum if their spectra overlap.  See full Motl blog here.

Roger Pielke, Jr., Director of the Center for Science and Technology Policy Research at the University of Colorado has just released the most comprehensive paper ever published on the subject of damage trends in Atlantic hurricanes. It will appear soon in the peer-reviewed journal Natural Hazards Review.

Is the planet warmer than it was? Yes. Is there any trend in hurricane-related damages in the United States (where good records of damages exist)? No—not after simultaneously accounting for inflation, population, and property values.

The silence associated with this important finding is deafening, and the results are consistent with other science that is being ignored in the current climate. One of Pielke’s co-authors, Chris Landsea, from the National Hurricane Center, has also found no trends in hurricane frequency or intensity when they strike the U.S. Sure, as is known to anyone who has studied hurricane data, there has been an increase in the number of strong storms in the past decade, but there were also a similar number of major hurricanes in the 1940s and 1950s, long before such activity could be attributed to global warming. See full story here.

This was the driest rain season ever in downtown Los Angeles and at many other locations in southwestern California. The 2006-2007 rain season, which began on July 1 2006 and ended on June 30 2007 is officially the driest ever in downtown Los Angeles since records began 130 years ago in 1877. Only 3.21 inches of rain fell during the season....nearly one foot or 11.93 inches below the normal for the season...which is 15.14 inches. Rainfall totaled only 21% of normal.

Rainfall was below normal in every month of this past season...with not one month receiving rainfall totaling one inch or greater. It is the first season since records began in 1877 not to have a single month during which one inch or more of rain was recorded. ironically, it follows just two years after the second wettest year on record (2004/05).

Why the dryness. The jet stream shifted north this year reflecting what appears to be a regime change underway in the Pacific Decadal Oscillation. Bill Patzert, a Jet Propulsion Laboratory scientist who researches the ocean’s role in climate variations noted stationary high pressure has pushed the moisture-bringing jet stream to the north, which has also allowed moist air to linger over Texas, he said. In California, he said, the drought situation resembles the 1950s and ‘60s rather than the unusually wet ‘80s and ‘90s, and it’s not going away.

“I think last year, unfortunately, people should plan on that as a preview of coming attractions, because there are no big patterns in the Pacific that are rainmakers,” he said. “There’s no El Nino galloping over the horizon to save us here.”

If indeed the Pacific regime change is taking place, expect more troublesome dry years in the southwest but much more snow in the Pacific Northwest and western Canada, where Whistler Mountain in British Columbia (near Vancouver) set a new snow record this season, with snowfall better than 40% above the normal.

The Idso’s reviewed the 2007 paper by Hinkel and Nelson entitled “Anthropogenic heat island at Barrow, Alaska, during winter: 2001-2005” in the Journal of Geophysical Research.  The authors report that since 2001 for the village of Barrow, Alaska (71.3°N, 156.5°W) - which has a population of approximately 4500 people - screen-level air temperatures have been recorded at hourly intervals by 68 data loggers that were distributed “to form an approximate grid pattern over the 150-square km study area” in and around the village.

On the basis of rural and urban group temperature averages for the period 1 December to 31 March of four consecutive winters, Hinkel and Nelson determined that the spatially-averaged temperature of the urban area was about 2°C warmer than that of the rural area, and that it was not uncommon for the daily magnitude of the urban heat island to exceed 4°C. In fact, they report that on some days the magnitude of the urban heat island exceeded 6°C, and that values in excess of 8°C were even recorded, while noting that the warmest individual site temperatures were “consistently observed in the urban core area.”

When attempting to measure a background global temperature increase that is believed to have been less than 1°C over the past century (which represents a warming on the order of 0.1°C per decade), it has to be appreciated just how difficult that task is when the presence of a mere 4500 people can create a winter heat island that may be two orders of magnitude greater than the signal being sought. Clearly, there is no way that temperature measurements made within the range of influence of even a small village can be adjusted to the degree of accuracy that is needed to reveal the true magnitude of the pristine rural temperature change. The only data of any value to this endeavor must be obtained from areas upon which there has been no historical human encroachment.

See story here.

There is an excellent review paper (McPherson 2007) that provides further documentation of the first-order role of land surface processes within the climate system.
Among the conclusions, Dr. McPherson writes,

“The transformation of regional vegetation coverage to different land uses, especially the substitution of native forest with cropland, can result in local or regional climate changes as significant as those ascribed to the enhancement of atmospheric greenhouse gases by humans. Hence, it is important that scientists help policymakers put into perspective the consequences of various sources of weather modification.”

This important role of vegetation as a component of the climate system was recognized, for example, by the 2005 National Research Council Report titled Radiative Forcing of Climate Change: Expanding the Concept and Addressing Uncertainties , but was not appropriately reported on in the 2007 IPCC WG1 Report (i.e. see Chapter 8 and Chapter 9). Dr. McPherson has provided a very effective peer reviewed publication that documents an important climate change issue that the IPCC inadequately communicated to policymakers.

Read full weblog here