Climate Change and Precipitation – Another IPCC And Climate Science Failure

Commentary, Climate, Frontier Centre

Focus of the Intergovernmental Panel on Climate Change (IPCC) is almost exclusively on temperature, particularly on warming.  That alone should condemn their work because different weather has different implications for different activities and in most cases temperature is of little concern.

They have the world in a panic for no reason and real issues are confused by their work

They have the world in a panic for no reason and real issues are confused by their work. For example, farmers and agribusiness need to know about temperature shifts, but a gradual change is of little concern and easily accommodated. IPCC claim temperature has increased 1°C in the last 100 years and that’s beyond a natural increase. It did not result in any negative impacts; in fact productivity has increased dramatically. Their future scenarios include more serious rates but every one to date has not matched even minimum increases.  As IPCC member Kevin Trenberth, wrote Wed, 14 Oct 2009, “The fact is that we can’t account for the lack of warming at the moment and it is a travesty that we can’t.” Now consider the changes in science, technology and society in those 100 years. Unless free enterprise is completely stifled by political ideologies, we can expect similar advances in the next 100 years. It will not be ’business as usual” as environmentalists assume.

Dramatic temperature changes, like the nearly 2°C drop in global temperature after Mt. Tambora erupted in 1815 are relatively short-lived and today would have far less impact. A possible example of a temperature change comparable to the IPCC predictions but a cooling was the 70-year decline from 1530 to 1600 (Figure 1). Lines delineate areas of arable land lost. Notice that between 1300 and 1600 approximately half the land went out of production. With today’s science and technology, especially genetic modification, adaptation is much easier. 


Figure 1: County of Berwick, England showing decreasing agricultural land.

Source: After Martin Parry WMO Cold Weather impact studies.

From year to year the single critical factor for plant growth is precipitation. Ignoring this allowed Michael Mann to use temperature as the sole cause of tree growth manifest in growth rings. Precipitation patterns are much more important for the short and medium term. The IPCC forecast increased droughts with global warming, which is counterintuitive. Higher temperatures cause increased evaporation and higher atmospheric moisture with greater potential for precipitation. The 2007 Report said, “very likely precipitation increases in high latitudes and likely decreases in most subtropical land regions, continuing observed recent trends.” This is based on the assumption greatest warming will occur in high latitudes, but it is also illogical. As is the assumption that current trends will continue. Temperature determines the air’s capacity to hold water. Polar temperature increase would have to be orders of magnitude greater than at middle and low latitude. But there they predict, “Decreasing water availability and increasing drought in mid-latitudes and semi-arid low latitudes.”

Droughts at these latitudes are cyclical not related to temperature, although the temperature can modify the intensity of the drought. They ignored this research because they are related to solar cycles.

Generally the IPCC avoids doing anything with water.

Generally the IPCC avoids doing anything with water. This is especially true in their work on the greenhouse effect. In Working Group I: The Physical Science Basis Section 2 is titled, Changes in Atmospheric Constituents and in Radioactive Forcing.

Section 2.3 discusses Chemically and Radioactively Important Gases but the only place where water vapor is mentioned is in a section on Stratospheric Water Vapor. This is a hangover from the original mandate to focus only on manmade causes of change, which is confirmed by a separate reference in Section 2.5 titled Tropospheric Water Vapor from Anthropogenic Sources. They changed the mandate because its limitations were identified, but they cynically changed little in the Report. It’s impossible to know how much water vapor is from human sources, if you don’t know natural amounts.

It is generally agreed that water vapor is 95 percent of the greenhouse gases by volume. There is complete disagreement about the effectiveness in delaying heat escape to space. Part of the problem is water vapor acts in some of the same wavelengths as CO2. Another is water exists as gas, liquid, or solid and each has a different effect. The complete inability of computer climate models to replicate the effect of clouds reflects these problems.  Ironically, the only time the IPCC acknowledge water vapor is in their attempt to overcome the saturation effect of CO2. Even if CO2 doubles there is an upper limit to temperature increase. They said temperature increase due to CO2 would increase evaporation and this would create a positive feedback causing temperatures to continue to increase. This is now proven incorrect and a negative feedback with increased cloud blocking sunlight as a result.

There is also the problem of the percentages of water vapor throughout the atmosphere. The IPCC incorrectly assumes CO2 is uniformly distributed. They don’t even grapple with the fact that water vapor in the atmosphere varies from almost zero in the polar regions to 4 percent in the tropics and is constantly changing from hour to hour. Rates of evaporation vary with temperature, but also with wind speed.

Computer models are built on data and temperature records are completely inadequate, which is a basic reason why the models fail.  Records of precipitation are even worse. Accurate measurements of rainfall are very difficult; it‘s even worse for snow. Even with adequate instruments, the number of stations is inadequate. Consider this comment about Africa. “One obvious problem is a lack of data. Africa’s network of 1152 weather watch stations, which provide real-time data and supply international climate archives, is just one-eighth the minimum density recommended by the World Meteorological Organization (WMO). Furthermore, the stations that do exist often fail to report.” (4 Aug 2006 VOL 313 Science). It is little better for most of the world.

The IPCC is a scientific, economic and political failure

For most middle latitude agriculture (30° to 65°) there are three primary sources of precipitation. Winter snowfall, summer rainfall and condensation in spring and fall. Measurements of the first two are less than adequate and the third is ignored. One summer, forecasts for a poor harvest on the Canadian Prairies were confounded. The obvious, but overlooked, explanation was that as much as 2 inches of moisture from condensation occurred in the late summer. This was more effective than rainfall because it occurred at ground level at night so little went to evaporation, and was available to the plant with reduced heat stress and was very widespread.

The IPCC is a scientific, economic and political failure.  Its political focus on CO2 diverts climate science from producing useful research to advance practical world knowledge and understanding of weather and climate. I am glad to rain on their parade: It must be eliminated.