As is now generally known, there has been no warming of the Earth's surface since 1998 at least. Prior to that time, we were informed that there had been a rapid warming of the Earth's surface and that it was caused by increasing CO2 concentrations in the atmosphere due to man using fossil fuels. The 2007 IPCC 4th Report still insisted that for 25 years the Earth had been warming. A newly published study using satellite temperature sensing specifically for detecting the Earth's surface temperature and minimizing that of the atmosphere above the surface, shows that the Earth's surface, contrary to reports, actually cooled from 1982 to 2006!
The paper is entitled Meteosat Derived Planetary Temperature Trend 1982-2006 by Andries Rosema, Steven Foppes, and Joost van der Woerd and was published in Energy & Environment, Vol. 24, No. 3 & 4 2013. They were very surprised to find the cooling trend they reported.
Earlier satellite data analyses, originated by investigators at the University of Alabama at Huntsville, used microwave sensors to infer the temperature from microwave emissions from oxygen molecules. Microwaves of different energies originated from various layers of the atmosphere. One set of data originated from an altitude of about 17 km. Another at an altitude of about 3 - 4 km. Then by looking at data taken at oblique angles of incidence, they inferred a temperature from an altitude of about 0.8 km. However, none of this data actually the Earth's surface temperature. Initially, this data on the lower atmosphere had shown a small cooling effect, but after many corrections were applied, the data yielded an increase of temperature of about 0.1 C/decade in the troposphere. The troposphere is the bottom about 10 to 11 km of the atmosphere and its temperature is not at all necessarily in direct proportion to the surface temperature. Indeed, increased cloud cover, water vapor, and CO2 in the atmosphere may cause an increase in the troposphere temperature even as it cools the surface temperature.
The Rosema, Foppes, and van der Woerd study used the infra-red radiation at 10.5 to 12.5 micrometers wavelength to directly measure the surface temperature of the Earth. The copy of the paper incorrectly says mm instead of micrometers. This infra-red radiation is in the mid-infra-red part of the electromagnetic spectrum, but close to the beginning of the far infra-red. The atmosphere is highly transparent at these wavelengths, provided there are no clouds. There is a minor effect due to water, but none due to CO2. The minor water absorption does add a small temperature component from the lower atmosphere to the larger component directly from the Earth's surface. This is nonetheless a huge improvement over the oxygen emission microwave emissions which have no surface component at all. The effects of clouds were filtered out of the data. The daily planetary temperature was approximated as the average of noon and midnight temperatures.
Such satellite measurements are critically important. The land surface temperature record is highly contaminated by urban heat island effects and by the bad sites chosen for weather station measurements. Very mysterious and undocumented changes to the raw data have been made to various time period sets of data. See here, here, here, here, here, here, here, here, here, and here, for instance. The authors of this study note that 10% of their own country, the Netherlands, is now hardened surface. Changes to ground cover, vegetation, or water surface coverage do have local effects on the surface temperature.
Indeed, they point to data for the area of the confluence of the Euphrat and Tigris Rivers in SE Iraq which showed a sudden warming when Saddam Hussein drained the extensive marshes there. With less water in this warm area, less evaporative cooling occurred and water vapor absorbed less incoming solar insolation up in the atmosphere, so the average temperature increased. They found another small area with warming in NW Tanzania. There, they believe that major mining increases led to a decrease in vegetation and then a reduction in evapotranspiration. The loss of that cooling caused surface temperatures to increase. They also noted a cooling effect near Lake Chad and Lake Nasser in their data which they attribute to the growing size of those lakes.
From 1982 to 2006, an ocean location west of France showed a temperature decrease of 0.78 C/decade. A location west of Senegal in the Atlantic showed a temperature decrease of 0.48 C/decade, which is less a decrease because of ocean upwelling in this area. More generally, they report that the Atlantic Ocean, Africa, and Europe show a negative surface temperature trend from zero to 2 C/decade. They observed that the greatest temperature decreases were in regions with greater cloud cover. In particular, the temperature decrease over desert areas was smaller.
Increased cloud cover is correlated with increased humidity of the air. More water vapor and more clouds both result in a lower surface temperature. While it is harder to separate out the effect of CO2 from the overwhelming effects of water vapor, increased atmospheric CO2 probably will also increase the cooling of the surface, as I have argued. In any case, the IPCC claim that a small surface temperature increase due to added CO2 will cause a much larger temperature increase due to more water vapor, is absolutely and clearly nonsense.
Yet sea level is rising?
ReplyDeleteTime Scales.
ReplyDeleteThe Earth's surface temperature, though cooling according to this report since 1982, is nonetheless higher than it was during the Little Ice Age. As a result, the great volume of the ocean water well below the surface, is still warming up. Measurements show this to be the case. Water expands as it warms and it also yields CO2, thereby causing the oceans to most rise and the concentration of CO2 in the atmosphere to increase. This is mostly a natural effect for both. The precise scale of the human effect is not yet determined, but it appears to be very small.