Temperature and Trust
Posted: February 19, 2015
A fundamental piece of evidence for a warming climate is the long term temperature trend. Particularly important is the trend in the past 100 years. Since the 1970s the temperature trend has shown a jagged but consistent increase. But can we trust the data? The short answer is yes. But a longer answer is needed to establish why we can trust it.
Three principal methods of temperature data collection and analysis have been used as climate science has progressed. These are the NASA Goddard Institute for Space Studies (NASA GISS) system, the NOAA National Climate Data Center (NOAA/NCDC) system, and the University of East Anglia Climatic Research Unit (CRU) in conjunction with the Hadley Centre (at the UK Meteorological Office) called for short Hadley/CRU or HADCRU. Some scientists were skeptical of the methods, particularly concerning data selection, data adjustment, poor station quality, the urban heat island effect, and the apparent over reliance on large and complex global climate models by the Intergovernmental Panel on Climate Change (IPCC). Then “Climategate” occurred in 2009 where a series of emails and documents were hacked from the Climatic Research Unit (CRU) raising further doubts.
Two such skeptics were Richard and Elizabeth Muller, who doubted several aspects of how the temperature records were collected and analyzed. They decided to find out for themselves what data could be trusted, and in 2010 they organized a group of scientists to reanalyze the Earth’s surface temperature record, looking particularly at concerns climate skeptics had identified. The group named themselves Berkeley Earth Surface Temperature (BEST). The result of that effort was published in a July 2012 press release which stated:
“According to a new Berkeley Earth study released today, the average temperature of the Earth’s land has risen by 1.5°C over the past 250 years. The good match between the new temperature record and historical carbon dioxide records suggests that the most straightforward explanation for this warming is human greenhouse gas emissions.”
Berkeley Earth shows their data compared to the other three methods on their website and reproduced on the right. Their current temperature plot clearly shows general warming from about 1900 to today, prior to which there is significant “noise” associated with poor quality data. The trend is clearest from 1970 on. The plot also shows that other principal compilations of temperature data coincide.
Click on figure to enlarge.
The scientists on the Berkeley Earth team are first rate and have shown their data and analysis in a very transparent way. They do know their “stuff” and can be trusted, as can the other methods.
Let’s Rely on the Data
Still there are just a few who, without any real scientific basis, claim the data are suspect. They disproportionately bias media coverage, forcing others to counter with valid information. For example, a recent blog by Christopher Booker refers to specific weather stations rather than the whole, and on that basis says all data are “manipulated”. That claim was nicely countered by Berkeley Earth. But the false information was picked up and broadcast on radio by Representative Gary Palmer, which again was countered, this time by FactCheck.org. These false claims need to stop. Admittedly none of us is aware of all facts and information, and perhaps some are innocent mistakes, but to blankly state something is true and then not yield when it is proven to be false takes us backwards, not forwards.