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“Best Science” and the Problem of Land-based Thermometers (Anthony Watts’s Surfacestations project)

By Indur Goklany -- May 22, 2009
Editor Note: Readings from land-based temperature records are in dispute, with most concern centering on how much of the recorded warming in recent decades is attributable to local versus global processes. Climatologist Patrick Michaels has recently brought attention to the problem, and the post below describes some preliminary findings of an on-going survey comparing real-world thermometer siting practices to recommended standards–and its potential impact on global warming in theory and practice.

President Obama and his administration take pains to stress that their climate and environmental policies will be informed by the best science available. And that is as it should be, but the entire task can be complicated by the fact that sometimes the best available science may not be good enough for the task at hand.

Anthony Watts’s report on the Surfacestations projectIs the U.S. Surface Temperature Record Reliable?—raises the distinct possibility that critical portions of policy-relevant climate science may be based on questionable, if not bad, data. And good science cannot be founded on bad data.

The Surfacestations project, initiated by Watts, is a survey of the 1,221 surface temperature stations that make up the U.S. Historical Climatology Network, a survey conducted by 650 volunteer citizens. This Network was established by NOAA to provide, among other things, accurate and unbiased long-term temperature trends for the United States.

Watts’s report is based on a survey of about 70 percent of the sites. It provides photographs and other documentary evidence that NOAA’s own siting standards have been not only compromised, but badly compromised. Many of these monitors are today located in airports and wastewater treatment plants, which are hardly representative of the earth’s surface. More importantly, over the years, towns and cities have grown around the monitoring sites, the immediate vicinity of the thermometers has been paved over with concrete or black asphalt, heating and air conditioning units have been introduced, and shade-providing trees have grown up or been chopped down. Most of these changes would tend to exaggerate the degree of warming that has occurred in the United States (and globally).

In other words, the U.S. surface temperature record is not reliable for making quantitative estimates of long-term temperature trends (although it may be possible to infer whether or not there has been some unspecified amount of warming). And if the temperature record from the United States, with its vast resources, is unreliable, so in all likelihood is the temperature record from most other countries (e.g., China, Russia, India, Brazil, and Mexico which cover large tracts of the globe but have historically lacked adequate resources and/or have been subject to internal discord and instability that can compromise data collection). In other words, the global surface temperature record is also unreliable. [This may also explain why the warming trend is stronger for surface data—the trend that the Intergovernmental Panel on Climate Change (IPCC ) uses for its reports and projections—than for satellite observations (for the period during which the two sets of records overlap).]

And if the surface data are compromised then so is everything that relies on that surface data, including:

· Quantitative estimates of the degree and rate of warming that has occurred in the past,

· Climate models that were constructed using this data,

· Results generated by those models, including what proportion of the warming may be attributed to well-mixed greenhouse gas emissions and projections of future climate change, and

· Benefits from any future reductions derived by using those models.

So while I wholeheartedly support the desire to use the best science in our decisions, it is equally important to ensure that the best science is, in fact, good science. Unfortunately, good science cannot be based on bad data.

And so long as the issues raised by Watts’s report are unresolved, there will be a cloud over climate-change science.


  1. Ed Reid  

    This assessment is generous to a fault. I admire your restraint.

    Collecting temperature measurements from sites prone to average errors greater than 2 C, as Watts documents, and reporting temperatures and temperature anomalies to two decimal place “accuracy” is more necromancy than science.

    We would be wise to spend a few $ millions on accurate temperature measurement before committing to spend ~$30 trillion (US only) trying to solve a potentially non-existent or relatively trivial “problem”, which we are incapable of solving on our own anyway.


  2. Andrew  

    Siting is not the only issue with the land data, of course, and a good overview of many of the issues is:

    Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, S. Foster, R.T. McNider, and P. Blanken, 2007: Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229.

    They do not address (and unfortunately, few seem to be interested in addressing) the equally important issues with the dubious Sea Surface Temperature measures, which rely on inhomogeneous and sparse data. If only we could survey the historical use of different SST measuring techniques (Buckets, etc.)


  3. rbradley  

    I just found that at Climate Science by Rogr Pielke Sr.: http://climatesci.org/2009/05/27/brief-overview-of-several-climate-science-research-findings/

    “conservative estimate of the warm bias resulting from measuring the temperature near the ground is around 0.21°C per decade (with the nighttime minimum temperature contributing a large part of this bias). Since land covers about 29% of the Earth’s surface, the warm bias due to just this one effect explains about 30% of the IPCC estimate of global warming. In other words, consideration of this one bias in temperature would reduce the IPCC trend to about 0.14°C per decade; still a warming, but not as large as indicated by the IPCC. [based on Lin, X., R.A. Pielke Sr., K.G. Hubbard, K.C. Crawford, M. A. Shafer, and T. Matsui, 2007: An examination of 1997-2007 surface layer temperature trends at two heights in Oklahoma. Geophys. Res. Letts., 34, L24705, doi:10.1029/2007GL031652; Klotzbach, P.J., R.A. Pielke Sr., R.A. Pielke Jr., and J.R. Christy, 2009: An alternative explanation for differential temperature trends at the surface and in the lower troposphere. J. Geophys. Res., submitted.] – for other uncertainties and biases in the monitoring of multi-decadal global average surface temperature trends; see).”


  4. Henri Suyderhoud  

    From all I can read about the connection between temperature measurements and CO2 emissions is that it is not necessarily connected, if at all. And there are sound scientific arguments that the Sun has more to do with temperature behaviors (note the plural) than CO2. I would rather see an effort of accurately watching sea levels, and come to a conclusion that the expected rise is so minimal as to be inconsequential. Unfortunately, even intelligent persons are getting fooled, perhaps because of fear!


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