Bishop Hill What's wrong with the IPCC - a guide for the layman
Jun 17, 2007 Climate: MWP Climate: Models Climate: Surface This is an attempt to summarise some of my previous postings on the IPCC process into a single article. What I'm trying to do is to make the case that there are signficant problems with the science that can be readily understood by the average reader. Even for a layman, these issues should give pause for thought.
The posting was inspired by this article by the Lazy Environmentalist - a blog I chanced upon while idly surfing my way around Technorati.com. The author seems to be, shall we say, an enthusiastic and unquestioning believer.
Temperatures are going up
Temperature records are derived from surface stations, satellites and radiosondes (weather balloons).
There are many problems with the surface temperature record. Firstly, it's not really a record of the temperature, but a theory of what the temperature record would have looked like if it had been measured correctly. The records from many stations are subject to significant adjustments to deal with issues like station moves, creeping urbanisation and so on. These adjustments are often larger than the trend which comes out at the end of the process. In other words the raw data shows cooling, but by the time they've adjusted it, it shows warming. The adjustments are largely shrouded in mystery, so it's not possible to say if they are reasonable or not. One surprising artifact of these adjustments is that the historic temperature record keeps changing - the past keeps being made to look colder so the warming seems ever greater.
A new website, surfacestations.org, has started to uncover a worrying failure of many temperature stations to site their instruments correctly - including several next to airconditioning units and carparks, and more than one next to a barbeque.
The weather stations are mostly on land, but most of the earth is ocean. While the sea surface record carries a greater weight in assessing the global temperature, the accuracy of that temperature is questionable because of this unevenness in the spread of the stations. The sea surface record, like the land record, is also subject to large adjustments which dwarf the warming which it is claimed has been detected. Here is an example of very shaky reasoning for a major adjustment.
The satellite and weather balloon records are much less convincing if you are looking for evidence of warming.
Temperatures in the past
The estimates of temperatures before widespread instrumental records became available are created from proxies - the temperatures are estimated from tree-ring widths and densities, and from ice cores. There are particular problems with the tree rings. Trees can grow faster or slower when temperatures rise, and it is not clear that the attempts by scientists to deal with this issue - by measuring trees at the upper tree line - have been successful. One scientist has found treeline samples from the same site showing both responses.
Another problem is that some temperature reconstructions have been suggesting declining temperatures in the second half of the twentieth century when, of course, things are meant to have warmed up rapidly. This embarrassing problem ("the divergence issue") has been quietly brushed aside by the IPCC, and in their report the offending records have been truncated at the point at which they start to fall away, so that the remaining records all show a rising trend. It is hard to see this as anything other than dishonesty.
The reconstructions with rising trends all use include a couple of particular species of trees - bristlecone pines and foxtails. These have both shown rapidly increasing growth rates in the twentieth century, something which is believed to be caused by non-climatic factors. Despite this being widely understood, the reconstructions have still been put forward by the IPCC as valid.
Most of the reconstructions stop in the 1990s. One simple test of whether they are reasonable or not would be to measure recent tree ring widths and to use this to derive a temperature. This could be compared to the actual temperature from the instrumental records. Despite all the money poured in to climate research, this has not been done and so questions over the accuracy of the reconstructions remain. And since we don't know if the reconstructions are valid, we can't say whether current temperatures are above, below or the same as, temperatures in warm periods in the past (eg "The Medieval Warm Period"). This extraordinary failure means that in essence we don't know if the problem is a problem we should worry about or not.
Data and code
One of the basic tenets of the scientific method is that work should be reproducible by other scientists. In order for climate scientists' work to be reproduced it is necessary for their data and the computer programs which transform it into results to be freely available. There are many instances of climate scientists refusing to release data, or "losing" it. This has happened with prominent scientists and key scientific papers. So some of the most important scientific work of recent years - work which underpins the IPCC process and the doom-laden results which it announces to the world - is not capable of being replicated. A reputable scientific body would disassociate itself from suspect papers of this kind. The IPCC embraces them.
The consensus
The IPCC's assessment report is said to represent the consensus view of 2500 scientists. Who these scientists are and how they made their happiness with this alleged consensus clear is not known. The comments of reviewers on the draft IPCC reports cannot be reproduced, despite this contravening the IPCC's own rules. The public have to accept the existence of a consensus on trust.
Reader Comments (2)
I have had a read of the Lazy Environmentalist website which you refer to above. Once was enough, never again. When I read items headed "The Peoples this, or the Peoples that" you can bet your bottom dollar that the writer has absolutely no interest in other people's opinions, rights or whatever. Think "The Democratic People's Republic of Korea" or "People's Republic of China" and others.