Â
The Dashboard follows the IPCC framework for detection of change. Dr. Pielke has explicitly excluded attribution and limited dashboard content to data.
The dashboard identifies detected changes only in heat waves and wildfires. Unfortunately, the data regarding these two classes of events are affected by factors with anthropogenic but non-climate related causes. I will not attempt to assign some specific percentage attribution to these causes, but merely to point out their existence.
Heat waves have significantly different definitions in different regions. However, determination of whether a heat wave exists is based on measured local temperatures. Local temperatures are affected by the Urban Heat Island (UHI) effect and by the quality of the temperature measuring stations in the affected areas. The NOAA graphic below shows the estimated temperature differences resulting from UHI across a range of land uses surrounding the urban center. The 7°F (4°C) difference from the rural surroundings to the urban center suggests that the urban center is in a relatively constant “heat wave” relative to its rural surroundings.
Â
Â
Measured local temperatures are affected by the quality of the temperature measuring stations acquiring the data. Class 3 – 5 measuring stations can exhibit positive measurement errors of 2 - 5°F. The errors introduced by measuring stations which no longer collect data but continue to report “measurements” are indeterminate. The combination of UHI and low quality measuring stations appear capable of creating a heat wave where one might actually not exist.
Wildfires have existed forever although measurements have improved over time. The data from the National Interagency Fire Center (NIFC) dates back to 1926. However, NIFC now reports only data from 1983, as shown in the graph below. Dr. Pielke’s dashboard uses the post-1983 data and therefore shows an increase. He has apparently judged that the pre-1983 data is of questionable provenance. However, even if the pre-1983 data were high by a factor of 2, there would still be a decreasing wildfire trend, or at least no detected change.
The other anthropogenic influence on wildfire data is the influence of causation. NIFC estimates that 88% of wildfires are human caused, and that 20% are the result of arson. Numerous factors determine whether a fire will become a wildfire and several of those factors are influenced by climate conditions, while others are influenced by forest maintenance and type of local vegetation.
Â
Â
Dr. Pielke’s avoidance of attribution is likely primarily influenced by the purveyors of “attribution science” who purport to be able to identify the influence of climate change on the frequency and/or intensity of extreme weather events to two decimal place precision, including those for which Dr. Pielke’s analysis has shown no detected change.
Dr. Pielke is currently developing a global version of the dashboard, which should show results similar to the US dashboard. Both dashboards will be continuously updated.
 Originally published here.