Thank you to those who had offered various rebuttals (in your own way) concerning my earlier postings on this thread. Frankly, climate change is not a subject of interest to me and the reason I have remain disengaged from this thread, until now. Recently I posted some comments as a counter argument to other posts which I feel do not represent the appropriate picture concerning climate change but are effectively mainstream narrative adulterated by politics rather than science.
What is climate change?
Climate change is merely a repackaged narrative of global warming concerning emission of anthropogenic greenhouse gasses on global temperatures. It is not about pollution control or waste management as some would like to frame the conversation. Having said that, what are the issues and the contention? Is it about saving the polar bears or reforestation as some would like to picture it?
Is there global warming?
The starting point I believe we need to address is whether indeed there is recent global warming as measured by available data. Ground-based temperatures stations indicate that the planet has warmed somewhere between 0.3 and 0.9 degrees Celsius since about 1850. Shorter sets of data collected by far more precise NASA satellites and weather balloons show a slight cooling trend in more recent years. While it has been argued that ground-based measurements are most reliable, the correlation coefficient between satellite and surface measurements is close to perfect agreement with computer models prediction supporting the correlation in warming between the lower atmosphere as at the surface.
Global climate models and their prediction value
Once I started to research on the subject of climate change the issues easily coagulate into two central themes : the efficacy of the models between prediction and observation; and the reliability of data sets going into the modelling. Once you understand the issues concerning these two themes, it would be disingenuous to conclude that the science on climate change is “settled”.
Largely on the basis of global climate models, which are based on what is known, what is assumed and simply guesses, the many models predict that continued emissions of anthropogenic greenhouse gasses will increase global temperatures anywhere from 1 to 3.5 degrees Celsius. What is notable is that most of the global climate models predict a far greater amount of warming than has actually occurred. The few climate models that come reasonably close to replicating past and present climatic conditions when historical data are entered are those that predict the least amount of future warming based on present trends. The two most prominent of those models, those of the National Center for Atmospheric Research and the U.K. Meteorological Organization, predict warming of only 1.2 degrees Celsius and 1.3 degrees Celsius over the next 50 years; the lower-bound estimates reported by the IPCC.
As the IPCC notes, “When increases in greenhouse gases only are taken into account … most climate models produce a greater mean warming than has been observed to date, unless a lower climate sensitivity is used.” In the April 2018 Journal of Climate, Nic Lewis and Judith Curry have re-calculated the equilibrium climate sensitivity (ECS) based upon the historical uptake of heat into the ocean and human emissions of greenhouse gases and aerosols. ECS is the net warming one expects for doubled atmospheric carbon dioxide. Their ECS ranges from 1.50 to 1.56 degrees Celsius. The average ECS from the UN is 3.4⁰C, roughly twice the Lewis and Curry values. It is not surprising that the observed rate of warming is now running at about half of the rate in the UN’s models.
Why has the global climate models failed?
The efficacy of any modeling is that it offers prediction that would subsequently be reasonably matched by observations. This had generally been not the case as demonstrated by the graphical presentation above.
Climate change is a complex subject and there are many things we do not know with certainty. Primary issues identified include :
Quality of data sets
The suspect quality of temperature data when they may be largely incompatible, imprecise, and incomplete nature of even recent land-based temperature records.
Masking
The idea behind the masking theory is that the most likely masking culprit according to the IPCC are anthropogenic aerosols, primarily sulfates, that reflect some of the sun’s rays back into space and thus have a cooling effect on the climate. As ambient concentrations of anthropogenic aerosols continue to decline (yes, global pollution is on the decline, not on the rise), the argument is that this artificial cooling effect will be eliminated and the full force of anthropogenic greenhouse gas loading will be felt in short order. However there are other observations that undermine this argument which I will not get into.
Climate sensitivity
The idea here is that the atmosphere is not as sensitive to anthropogenic greenhouse gases as the models assume. The argument for moderate climate sensitivity to anthropogenic greenhouse gas emissions largely rests on three observations:
• Carbon sinks continue to absorb more carbon dioxide than can be explained.
• 98% of all greenhouse gases are water vapor, and many atmospheric physicists, most notably Richard Lindzen of MIT, doubt that a doubling of anthropogenic greenhouse gases would have much climate effect absent a significant change in the concentration of atmospheric water vapor.
• A warming planet would probably lead to increase cloud cover, which in turn would have uncertain affects on climate. Concedes the IPCC, “The single largest uncertainty in determining the climate sensitivity to either natural or anthropogenic changes are clouds and their effects on radiation and their role in the hydrological cycle … at the present time, weaknesses in the parameterization of cloud formation and dissipation are probably the main impediment to improvements in the simulation of cloud effects on climate.”
Is there consensus?
It depends on your source, information selection and interpretation. If you are a global warming alarmist then your weight is on the IPCC report and in particular the executive summary of that report which is a product written not by the scientists who produced that report but by a small, politically appointed executive committee which states: “the balance of the evidence suggests” that human influences explain some of the detected warming. If you are into details then you will note the contrast in the statement with appears on page 439 of the report: “Finally, we come to the difficult question of when the detection and attribution of human-induced climate change is likely to occur. The answer to this question must be subjective, particularly in the light of the large signal and noise uncertainties discussed ….” Or on page 411, the statement is even clearer: “Although these global mean results suggest that there is some anthropogenic component in the observed temperature record, they cannot be considered as compelling evidence of clear cause-and-effect link between anthropogenic forcing and changes in the Earth’s surface temperature.” (source:2nd assessment IPCC)
The contrasting view of IPCC’s cautious concern about the scientific evidence for global climate change is reflected in the Heidelberg Appeal signatories of 4,000+ scientists (70 of whom are Nobel Prize winners) which warns the industrialized world that no compelling evidence exists to justify controls of anthropogenic greenhouse gas emissions.
A 2013 study done by the American Meteorological Society showed that 52% of professional members believed the cause of global warming was “mostly human”.
Bottom line what is the issue?
As mentioned, the various global climate models predict a range of 1 to 3.5 degrees Celsius in global warming with the more reliable models to date indicating it to be in the lower range. The “sky is falling” crowd which has piggy backed on the higher range to push for immediate action has to-date proven to be alarmist by observed data against prediction and the assumed trajectory. The sceptics has argued that at the lower range it may well be within the range of climate variability rather than man made given the many unknowns. In terms of economics, in my view the Paris Accord is simply a fraud to push spending (estimated to be up to Euro 46 trillion) to seek an improvement of merely 0.05 degrees Celsius that is well within the scope of prediction range regardless of any action that may be taken or not.