There has been much controversy over “hottest” years or months lately, mostly citing differences of less than one degree Fahrenheit. In a sane world such arguments should be academic, but policy advocates conflate any inkling of apparent support for their position into dire predictions that demand immediate action.
What is the real temperature? The answer is fraught with great uncertainty because it depends on where you put the thermometers, which readings are counted, and how they are averaged.
Two experiments demonstrate the problem. The newest, still on-going, experiment is being conducted at Oak Ridge National Laboratory. They set out an array of five thermometers in a field adjacent to a building (see photo below). They found that night time temperatures become warmer as the building is approached. This is true whether the wind is blowing toward or away from the building. The researchers suggest this happens because of infra-red radiation from the building. So, which thermometer records the “true” temperature? (See more of the story here).
I’ve reported on the second experiment before (see here). NOAA, keepers of the official temperature record, maintains two sets of stations, the older U.S. Historical Climatology Network (USHCN) and the newer U.S. Climate Reference Network (USCRN). The newer stations are located away from warming urban influence. These stations record temperatures 0.5°C on average, up to almost 4.0°C (0.9°F to 7.2°F) lower than the older stations upon which the official record is based.
These experiments support a 5-year study by Anthony Watts which showed that with a combination of poor station siting and “adjustments” performed by NOAA, the official U.S. temperature record is warm-biased and does not reflect the true temperature.
Perceived trends in the surface temperature record are used by advocates to attribute a cause, such as carbon dioxide emissions, and to pretend there is a crisis. But, as these data show, the causes are complex and very uncertain, too uncertain to be the basis of major policy decisions. But much money depends on maintaining the mythical crisis, from subsidies for wind and solar projects to the indulgence of renting “clean” air through the trading of carbon credits.
One other question: What is the “right” temperature for this planet?