Editors Note: Many media outlets have been pushing the idea that summer 2023 was a record breaking “hottest summer ever.” However, when the actual temperature data is examined, it says otherwise. This lack of journalistic review for the most basic things like the actual temperature data is a commentary on the sad state of journalism today.
Guest essay by Larry Hamlin (originally published on WUWT)
A recent WUWT article addresses the failure by climate alarmist media and scientists to utilize NOAA’s July through August summer maximum temperature data resulting in their false “hottest summer ever” headlines for the year 2023 with this summer characterized in the Los Angeles Times (L.A. Times) article as having been a “record breaker”.
The L.A. Times alarmist article referenced in this WUWT post was not based on measured global August average temperatures but instead was built upon the use of global average temperature anomaly measurements (Times article statement shown below).
“August was about 2.7 degrees warmer than preindustrial averages.”
The global August average temperature anomaly value represents the statistical temperature difference determined between the year 2023 global August average temperature outcome compared to the global August average temperatures compiled since 1895.
The global August temperature anomaly measure tells us nothing about August average temperature outcomes at any specific location on the globe nor does it tell us anything about August average temperature anomaly measurements at any specific global region.
The world’s oceans comprise about 70% of the earth’s surface with the land surfaces representing the remaining 30% that are spread out across the far flung 7 continents with the huge distance separations between these continents making the use of global average outcomes to characterize these regions completely invalid.
Additionally, the Times and other climate alarmist news media falsely characterize the global August average temperature anomaly as representing the “hottest summer ever” when such claims require the use of August maximum temperature measurement data at specific global locations. Likewise, use of summer July through August 2023 maximum temperature data would be required to make “hottest ever” claims regarding the summer of 2023 as noted in WUWT article.
Another WUWT article shown below followed up on the prior article by addressing NOAA’s recent contiguous U.S. year 2023 September average temperature anomaly and absolute temperature data updates.
The first NOAA graph in this article shows the monthly contiguous U.S. data that include both August 2023 (August proclaimed as the hottest August ever) and September 2023 average temperature anomaly values since 2005 using NOAA’s most accurate USCRN set of measurement stations across the U.S. that are sited away from temperature altering artificial heat sources which plague the majority of USHCN temperature measurement stations.
NOAA’s monthly temperature anomaly outcome is calculated based on using monthly average temperature values defined as (Tmax + Tmin)/2 = Tavg with the average temperature value compared to prior year averages over a defined long-term period to determine time dependent differences.
The scale on the right-hand side of NOAA’s graph shows degrees F (the scale on the left is degrees C) with this value determined by taking each monthly Tavg compared to the average Tavg of all like months over a specifically defined period of years. The September 2023 temperature anomaly outcome is +1.93F with this anomaly value exceeded by 4 prior years going back to 2015.
The anomaly data shows that neither the August nor September 2023 average temperature anomaly outcomes across the contiguous U.S. are trending significantly from prior values with these results clearly not supporting alarmists claims that there is a global “climate emergency”.
The second NOAA graph in the prior article (shown below) indicates the monthly maximum temperature measurements (Tmax temperature values) for the summer months from July through September of year 2023 (in 2023 being 85.36 degrees F) compared to that same summer measurement period for all yearly July through September summer month intervals going back to 1895.
The graph clearly shows that the July through September summer of 2023 was clearly not the “hottest summer ever”.
NOAA’s July through September yearly summer temperature data on their website is available for maximum, average and minimum temperatures as shown below with NOAA’s data establishing that the increasing trend of Tavg (orange graph with this value being (Tmax+ Tmin)/2 as described above) is clearly driven by the significantly increasing trend of Tmin (blue graph) versus Tmax (red graph).
Shown below is NOAA data for the period from June through August which is considered the “meteorological” summer period versus the “calendar” summer from July through September shown above.
Again, the June through August summer month period was not the “hottest summer ever” as the Tmax data clearly shows. The outcome of Tmin (blue graph) driving increasing Tavg (orange graph) is also clearly present.
The climate alarmist news media and climate activist scientists have been misleading the public with false claims of the “hottest summer ever” based on using summer average temperature anomaly values derived from Tavg while ignoring summer maximum temperatures (Tmax) with the maximum temperature data clearly showing the U.S. has not seen a “hottest summer ever” outcome in year 2023.
The sharply increasing minimum temperatures are significantly driven by Urban Heat Island impacts (UHI) as described in a recent significant study (shown below) at this WUWT link by Dr. Roy Spencer whose study evaluated how increasing population density around cites over the last 100 years have resulted in artificial heat sources (buildings, roads, airports, vegetation, traffic, air-condition vents, etc.) impacting temperature measurements at stations in these areas across the U.S.
These artificial heat sources significantly impact measurement of minimum temperatures as the stored heat in these artificial sources contribute to increasing temperatures after the sun has set as reflected by the NOAA graphs above that clearly show increasing minimum temperatures (blue graphs) have been climbing since about the mid 1970s and are driving up average temperature measurements as addressed in Dr. Spencer’s important and comprehensive study.
The key conclusion from Dr. Spencer’s study is as follows:
“But for the average “suburban” (100-1,000 persons per sq. km) station, UHI is 52% of the calculated temperature trend, and 67% of the urban station trend (>1,000 persons per sq. km). This means warming has been exaggerated by at least a factor of 2 (100%).”
The failure of climate alarmists to use NOAA summer maximum temperature measurements and instead rely on temperature anomaly related analysis using summer average temperatures in making flawed “hottest summer ever” claims is a major error. This error is applicable at global, regional, national, state, county, and city levels.
Originally posted at WattsUpWithThat, reposted with permission.