Climate Change is based on three dependent Theories.
Theory One – Green House Gas Theory – the first doubling of Carbon Dioxide content in the atmosphere is predicted to cause up to 1 degree C of warming in the atmosphere due to increased long wave back radiation. Issues which limit further temperature rise are the logarithmic decline in the amount of back radiation as CO2 concentration increases and overlap/saturation of the back radiation spectrum by existing Water Vapor. Most people are surprised to hear that the estimated amount of the GHG effect that is attributed to CO2 in the peer reviewed scientific literature is a range from as low as 2 % to as high as 45 %. The amount of effect will vary by the second with latitude, altitude, time of day/night, over land/water, season, cloud cover/type and humidity, etc. so programming the changing effects in a Model is very difficult so most climate models use equations and relationships that approximate 15 to 20%. The only way to test or verify this is make projections and test against real world temperatures but it is hard to separate out natural variability.
Theory Two – Amplification/Positive Feedback Theory – the predicted temperature rise due to increased back radiation is theorized to increase humidity in atmosphere which is predicted to cause 1 to 4 Degrees C of additional warming which is 3 to 4 times as much as the predicted impact of the increase in CO2. The main issues are that the predicted humidity rise and the resultant temperatures increases have not been observed in the atmosphere by decades of balloon and satellite observations so the Climate Sensitivity to increases in CO2 appears to be over estimated. The largest temperature rise was predicted by the climate models for the lower Troposphere in latitudes around the equator (20S to 20N)(Search “missing hot spot”). Climate models also do not do a good job of handling clouds – formation, movement, albedo, etc. and vertical energy transfers like storms and loses to space.
Theory Three – Catastrophic Climate Change Theory – The additional warming from the first two theories is theorized to cause Catastrophic Changes to the Climate and dramatically increase disastrous climate events. Main issues are both the actual Global Temperatures and the rate of temperature increase are running way below Computer Model Forecasts. There has been very little increase in global temperatures in the last 19 years and the link between warming and increased climate disasters is not apparent. There is no scientific link between Mild Warming and Catastrophic Climate Events so if there is only mild warming then no expected increase in catastrophic events. There are also positive benefits of increased CO2 and mild warming such as increased plant growth, less fuel use and less deaths to cold weather
The Positive Feedback Theory is predicted to cause the majority of the warming but the empirical real world data shows no increased humidity and very little increase in global temperatures for the last 19 years despite a 40% rise in CO2 concentration. Climate Sensitivity forecasts are being reduced as there are now 14 published papers with climate sensitivities below the IPCC AR5 estimates. The lower sensitivities to CO2 are due to increased attribution to Natural Variability.
Is Atmospheric CO2 Content Really the Dominant Driver in Global Temperatures?
Interesting graphs below or attached.
Please read the recent Congressional and Senate Testimony (pdf attached) from Dr Christy who co designed the first temperature/weather satellite system for NASA and contributed to the UN IPCC reports. He has been one of the esteemed members of the IPCC Consensus group but he is now questioning why the data does not match with the theories.
Comment on NASA site: I have previously read the NASA site and agree with most of it. Of course the world has been warming up, the glaciers melting, etc since the last ice age and more recently since the Little Ice Age which ended in the mid 1800’s. The real discussion is how much of the warming since 1950’s may be due to CO2 and specifically due to human caused CO2. Scientists cannot even agree when the added human CO2 levels were enough to actually cause a detectable amount of temperature change – some say 1950 – some 1970’s. The NASA site is very simplified and basically says that they cannot figure out why the earth is warming up or why the 1980 to 1998 period warmed quickly so it must be due to the increase in CO2! The Consensus part is just statements that all the Science Societies do not have a better explanation for the warming so they agree that it is likely that it is caused by the increase in human CO2. They do not really know but they have advanced theories on how the change in CO2 could work and that is what is programmed into the models that are over estimating the warming compared to the measured data. Time to go looking for a new or more complex explanation.
Follow the Scientific Method – propose theory – Test against real data – Adjust theory – retest – etc.