It has very long been known that higher humidity causes a reduction in the atmospheric lapse rate (the temperature gradient) and therefore a reduction in the surface temperature. There is also a strong cooling of surfaces when water evaporates due to the very high latent heat of evaporation of water. These are facts that have long been well-known, but which are greatly played down by the proponents of the wild and woolly scare story of catastrophic man-made global warming or AGW. These are certainly very strong negative feedbacks to any warming of the Earth's surface due to any cause, whether increased solar radiation or a hypothetical increase in back-radiation due to increased carbon dioxide.
But what is the effect of clouds formed by increased water vapor due to a hypothetical warming of the surface due to increased carbon dioxide or due to any actual warming? Magnus Cederlof examined the CERES satellite cloud cover data to see how it correlates with the yearly variation in global irradiance. He also examined the separate data sets for the Northern and Southern Hemispheres. The data he presents is very informative, though he presents it in an article with a number of serious errors in it. One of the more serious errors is his claim that his data provides strong evidence that the Svensmark theory of solar effects on the cosmic ray nucleation of clouds is correct. These errors aside, his plots of cloud cover versus solar radiation are extremely useful.
The data generally shown on cloud cover for the entire globe seems to provide a difficult to interpret effect, but one that implies there is no simple correlation between solar radiation and cloud cover.
The data for the entire globe, with the solar insolation given in blue [the units are W/m2, not kWh/m2] and the percentage of cloud cover averaged from 2000 to 2014 given in red, is:
The greater the solar irradiance of the Northern Hemisphere in the plot above, the greater the cloud cover.
The data plotted by Magnus Cederlof for the Southern Hemisphere correcting the irradiance units to W/m2]:
It is now clear that as the Earth warms in either hemisphere, there is a reaction by water to that warming to cause an increase in hemispherical cloud cover.
Magnus Cederlof then correctly makes the critical point that one feedback response of water to an increase in Earth temperature is an increase in cloud cover, which cools the surface. Thus, increased temperature is counteracted by a negative feedback by clouds and not the positive feedback proclaimed with great certainty by the falsely claimed "settled science of catastrophic anthropogenic global warming."
So there we have it. When the Earth's surface temperature rises, water causes three powerful negative feedbacks to reduce that temperature rise. These are:
- Cooling by the evaporation of water, which increases water vapor in the atmosphere.
- Increased water vapor reduces the lapse rate in the troposphere, dropping temperatures in the lower atmosphere.
- Cloud cover increases, preventing solar radiation from reaching the Earth's surface and warming it.
It is mind-boggling that the U.S. government has spent about $100 billion on climate and climate effect research and development in the name of such incredibly wrongheaded science. The United Nations and most of the European nations have also acted on this "science" house of cards in a similar manner. The cost of doing business and the cost of living for hundreds of millions have been sadly boosted in the name of this nonsense. Millions of people have either lost their jobs or were prevented from getting the jobs that might have been created. Terrible wrongs and harms have been perpetrated on billions of human beings both by preventing them from enjoying their individual freedoms and by decreasing their material living conditions. The benefits to humans throughout the world that would have accrued had millions of people used their time more productively and had capital been more rationally invested have been trashed. Instead, governments enjoyed exercising more power over individuals. Dishonest politicians, some dishonest businessmen, and some dishonest scientists enriched themselves by taking advantage of this baseless scare. The vast majority of mankind has nothing to show for it but losses.