Anyone wishing to understand why I don’t trust IPCC (the UN Intergovernmental Panel on Climate Change) science need only look at the 2007 IPCC Climate Change Synopses Report. Chapter 3 is one of my favorite chapters, it deals with predicted changes in Climate and is full of wild ass guesses. Section 3.2 is titled Projections of Future Changes in Climate. It begins with the following statement
For the next two decades a warming of 0.2 degree C is projected for a range of SRES emissions scenarios. Even if the concentrations of all GHG’s and aerosols had been kept constant at year 2000 levels, a further warming of 0.1 degree C per decade would be expected. Afterwards temperature projections are increasingly dependent on specific emissions scenarios.
The very next paragraph states
Since the IPCC first report in 1990, assessed projections have suggested global temperature increases between 0.15 and 0.3 degree C per decade from 1990 to 2005. This can now be compared with with observed values of about 0.2 degree C per decade, strengthening confidence in our near-term projections.
I wonder what the IPCC thinks now. Just about everybody (except NASA) thinks we had a short term temperature peak in 1998. Since then we have had 15 years of relatively stable climate. 8 years of warming followed by 15 years of stasis.
Last December, a temperature chart in a draft of the next IPCC report (AR5) started making the rounds at the various skeptical web sites including Watts Up With That? Here is that chart.
The color bands in the chart represent the temperature projections the IPCC has done since it’s first study in 1990. The black bars are measured temperatures. Four projections have been issued, FAR in 1990, SAR in1995, TAR in 2002 , and the AR4 (orange) which is the 4th report issued in 2007. The color bands represent a prediction that is supposed to include 90% of all possible outcomes with 5% percent being higher and 5% being lower than the color band. The orange band was constructed in 2005 and published two years later.
Just 7 years later, the world temperature is below the range predicted. We are in 5% land according to the IPCC. That’s quite a bit off, just 7 years after the study and only 5 after publication. 2008, the first year after publication was the first year to land completely outside the curve boundary.
The last data included in the graph is now over 2 years old. How have we been doing since 2010. Let’s look at the UAH satellite data
The running 13 month average is the same as it was in 2000 and .2 degree C below the peak encountered in 1998. I’d be the first to admit that any conclusion based upon short term data is stupid in a climate cycle that averages 100,000 years per cycle. The recent past does not prove the science behind global climate change right or wrong, it merely points out that the IPCC practices sloppy science full of wild guessing.
They never should have made such specific projections. Natural climate variation makes any specific projection problematic. Volcanic eruptions mess things up in the short run (Mt. Pinatubo in 1992 is an excellent example). The IPCC has difficulty modeling periods before 1850. They have trouble with the Little Ice Age and the Medieval Warming Period. Climate modeling has come a long way….but it still has a long way to go. They should have been more circumspect.
Imagine trying to predict changes in your speed relative to the ground while walking on a moving train. You know your walking speed, but if you don’t know what the train is doing, it is extremely difficult to accurately predict your ground speed. The IPCC is trying to predict changes caused by man without knowing how to accurately model the natural system.
They were bound to be wrong. Getting the right answer fifty or one hundred or one thousand years into the future is a very difficult science problem. The cause is not well served by IPCC wild guesses.