Global warming theory fails again

It is a tenet of catastrophic anthropogenic global warming theory (CAGW) that our carbon dioxide emissions are the major cause of recent global warming. Although carbon dioxide is a very weak greenhouse gas, CAGW theory holds that it is enough to start the warming process which, in turn, evaporates water, and water vapor is a very strong greenhouse gas. CAGW proponents ignore the fact that more water vapor in the air produces clouds which block the sun (more on that below).

It follows from CAGW doctrine that more carbon dioxide emissions should increase the humidity of the air, thus establishing an enhanced greenhouse effect. Is that happening?

A new paper, Trends in U.S. surface humidity, 1930 – 2010, Journal of Applied Meteorology and Climatology, finds just the opposite: “Average long-term trends (1930 – 2010) indicate that temperature has warmed, but little change has occurred in dewpoint and specific humidity.” In other words, the mechanism for CAGW’s enhanced greenhouse effect is not happening according to observational data.

How, then, do we account for warming in the 20^th Century? Back in 2005, Dr. Roy Spencer published a book: “The Great Global Warming Blunder: How Mother Nature Fooled the World’s Top Climate Scientists” (see my review here). In that book Spencer proposed that “The most obvious way for warming to be caused naturally is for small, natural fluctuations in the circulation patterns of the atmosphere and ocean to result in a 1% or 2% decrease in global cloud cover. Clouds are the Earth’s sunshade, and if cloud cover changes for any reason, you have global warming — or global cooling.” Could such a small change in cloud cover be significant?

A new paper just published in the Journal of Climate finds that global cloudiness has decreased over the past 39 years from between 0.9 to 2.8% by continent. See graphs and a discussion of the paper at WUWT here.

The first paper falsifies the major CAGW tenet; carbon dioxide has been increasing but there has been no increase in humidity. The second paper provides confirmation of a natural control of global temperatures.

Global Warming

Global warming is the increase in the average temperature of Earth's near-surface air and oceans since the mid-20th century and its projected continuation. According to the 2007 Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the 20th century.Most of the observed temperature increase since the middle of the 20th century has been caused by increasing concentrations of greenhouse gases, which result from human activity such as the burning of fossil fuel and deforestation.Global dimming, a result of increasing concentrations of atmospheric aerosols that block sunlight from reaching the surface, has partially countered the effects of warming induced by greenhouse gases.


Climate model projections summarized in the latest IPCC report indicate that the global surface temperature is likely to rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the 21st century.The uncertainty in this estimate arises from the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates of future greenhouse gas emissions. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers, permafrost and sea ice. Other likely effects include changes in the frequency and intensity of extreme weather events, species extinctions, and changes in agricultural yields. Warming and related changes will vary from region to region around the globe, though the nature of these regional variations is uncertain.As a result of contemporary increases in atmospheric carbon dioxide, the oceans have become more acidic, a result that is predicted to continue.

The scientific consensus is that anthropogenic global warming is occurring. Nevertheless, political and public debate continues. The Kyoto Protocol is aimed at stabilizing greenhouse gas concentration to prevent a "dangerous anthropogenic interference". As of November 2009, 187 states had signed and ratified the protocol.