Friday, July 27, 2007

One sense in which global warming IS man-made

John Brignell of Numberwatch:
When you are trying to troubleshoot an instrumentation system (whether it is in examining a PhD thesis or facing a major industrial crisis) there are, self-evidently, two vital areas you need to address:

1. The physical process of data acquisition
2. The computational process of Data handling

The central problem with data acquisition, now that data conversion is largely standardised through advances in electronics, is the housing and siting of sensors. Sometimes the problems are glaring, such as caking with mud or salt, but often they are more subtle and veiled. Particularly difficult are cases where instrumentation interacts with nearby systems (see appendix below for an example where an expensive court case was averted).

Data handling is an even greater problem, especially when “intuitive” or obscurely argued methods are implemented. Even if we discount the possibility of deliberate fraud, the power of the human subconscious to influence outcomes is a known but difficult to quantify hazard, especially in computer programs.

In considering data handling for climate monitoring in these terms, we now have the advantage of new information on siting and a description, though not a perspicuous one, of alterations made to original data.

We have long known that there have been examples of badly sited monitoring stations. The late John Daly showed seven years ago an example of bad siting, while, incidentally, raising the question of whether the surface record was as reliable as we were led to believe and proposing improvements of methodology. Daly’s analysis has not only stood the test of time, but has been vindicated by recent developments. The satellite record continues to show little or no change while the surface record shows what s alleged to be a continued rising trend.
Brignell shows two graphs displaying the difference between satellite and surface measurements in recent decades, and then goes on:
This is what John Daly wrote seven years ago about surface stations:
The only way surface data can be used with any confidence is to exclude all town/city and airport data - no exceptions. Only rural sites should be used, and by `rural’ is meant strictly `greenfields’ sites where there is no urbanisation of any kind near the instrument. Even when greenfields stations are used, those which are technically supervised (eg. managed by scientists, marine authorities, the military etc.) should be treated with greater credibility than those from sheep stations, post offices and remote motels.
As it turns out, the temperatures recorded by urbanized weather stations skew the surface averages enough to account for most of the claimed global temperature increase of the past century.

Brignell also demonstrates faults in the processing of the data.

So, in a sense, global warming really is man-made -- through man's faulty collection and processing of the critical data.

UPDATE: The American Association of State Climatologists, while apparently unconcerned about the physical location of weather stations, petitioned Congress in March to address the antiquated equipment and obsolete data collection techniques that plague America's weather station network.

(Thanks to for the links)