We just came across the data compiled by Dr. Roy Spencer in a June 6, 2013 article titled STILL Epic Fail: 73 Climate Models vs. Measurements, Running 5-Year Means. He plots predictions from 73 climate models showing their mean prediction. He also plots 6 data set s on observations made by satellite and balloons. The result is shown in Figure 1 taken from his blog.
Figure 1. Temperature data, model predictions versus real observations.
If we drew a linear regression line on the observed data, we would get a temperature rise of about 0.4° versus a mean model increase of about 1.1°. What is more significant is that ALL models begin to diverge from observed data around 1998. None are predictive.
Trying to tie the scale labeling to the scale making is tricky but looking at the observed data, we see peaks at 1981, 1989, 1996, and 2004. Although the data set is small it appears to have a periodicity of about 8 years. This may represent a short-term climate cycle. This in turn begs the question of what are the possible longer-term cycles? And then the grand daddy of them all, the roughly 100,000 year cycle of glaciation revealed by the Vostock ice core data: What Is Your Carbon Foolprint?
Anybody who attempts to model economic data on markets knows that it is absolutely crucial to back-test their models, preferably on 100 years worth of data. Indeed, failure to do so resulted in the collapse of Long Term Capital Management in 1986, an event that almost brought down the global financial system. So with much more riding on it, we would expect climate modellers to back-test their models at least 400,00 years in order to replicate the Vostok data and validate their assumptions.
An article posted on Judith Curry’s website by Pat Michaels and Chip Knappenberger titled Climate models versus climate reality, reviews over 100 climate model runs and compares them to observed data. Figure 2 provides a graphical representation of the comparison.
Figure 2. The forecast and observed temperatures for the middle troposphere.
As they explain:
The troposphere is the earth’s active weather zone, and it extends from the surface to around 40,000 feet. It’s deeper where the atmosphere is warm, as in the tropics, and shallower at higher latitudes. All significant storms, from massive winter cyclones to gullywashing summer thunderstorms are in the troposphere.
The authors further state:
Rain and snow are largely dependent upon the temperature difference between the surface and the mid-troposphere. When there’s little difference, air in the lower atmosphere does not rise, meaning that the vertical motion required to form a cloud is absent. When the difference is large, moisture-laden surface air is very buoyant and can result in intense rain events.
If modellers can’t get the mid-troposheric data right, they cannot correctly model cloud cover and precipitation which has a major effect on surface temperature. There is extensive discussion of surface temperature with references to a number of r4ecewnt papers which together place the rate of warming due to CO2 emission near the lower bound of the IPCC estimates.
They have a lengthy discussion of model test results which may be summarized with their statement:
This is a devastating indictment of climate model performance. For periods of time longer than about 20 years, the observed trends from all data sources fall beneath the lower bound which contains 95 percent of all model trends and in the majority of cases, falls beneath even the absolute smallest trend found in any of the 102 climate model runs.
The authors conclude that:
Based upon these and other lines of evidence (laid out in our numerous scientific publications, books, blogs articles, social media (see publications listed here and here for example)), we conclude that future global warming will occur at a pace substantially lower than that upon which US federal and international actions to restrict greenhouse gas emissions are founded.