The Biden administration's Fifth National Climate Assessment (FNCA) report makes alarming claims about rapid warming across the United States that exceeds global warming by 60%, but examination reveals that claim is 100% bogus.
Experts have discovered various flaws in the FNCA, including its pineapple versus apple temperature comparison (i.e., comparing global land and sea temperatures to contiguous U.S. land-only temperatures) and the merging of geographically unrelated temperature datasets. These obvious flaws have produced a distorted outcome.
An excellent breakdown of the flaws and errors (manipulation-fraud?) can be found here, which includes a discussion of the U.S. metropolitan Urban Heat Islands impact.
Correcting for the truly misleading pineapple-to-apple comparison that found U.S. temperatures warming 60% faster than global temperatures since 1970 is rather straightforward. Simply eliminate the cherry-picked 'pineapple', so to speak.
The appropriate temperature comparison is global land temperatures versus U.S. land temperatures, which NOAA, the nation's chief climate agency, updates and publishes every single month.
This correct comparison reveals that since 1970, global land temperatures have actually risen 18% faster than U.S. land temperatures.
The FNCA's purposefully including global ocean temperatures in their comparison skews their results significantly. Oceans represent 71% of Earth's area, with a warming rate that is only 42% that of global land, since 1970. Thus, by including ocean temps in their comparison, it assures that U.S. land-only temperatures would have a faster warming rate.
By correcting for the FNCA mismatch, what are the results of comparing NOAA global land temperatures and U.S. land temperatures starting in January 1895?
This chart compares those two exact monthly temperature datasets. (Again, unlike the FNCA comparison, both datasets represent temperature readings from land-based climate stations.)
As the two plots and their respective linear trends make clear, since 1895, global land temperatures have been warming faster than U.S. contiguous land temperatures.
In fact, over the long run, global land temperatures have increased 1.4 times faster than U.S. land temps.
Another method of analysis is to examine shorter-term warming rates to determine how NOAA global land and U.S. land temperatures differ in rates of warming.
The second chart does this by plotting the moving 10-year (aka, moving 120-month) warming and cooling rates for both the monthly land datasets, starting with December 1904.
As is shown, from the end of 1904 through October 2023, both datasets exhibit a back-and-forth cycling between warming and cooling trends.
The chart also displays the 5-year averages of the moving 10-year trend comparison, which confirms the essential facts: consistently, global land temperatures over shorter periods have been warming faster than U.S. temperatures. From the early 1900s to present time, the mean of the global 5-year average exceeds the U.S. mean by 25%.
Furthermore, the FNCA report fails to mention that, per NOAA, contiguous U.S. temperatures have experienced a cooling trend since April 2011 (over 12 years) at a rate of -0.34°C per century, while during the same period, NOAA's global land temperatures have been warming at a rate of 4.17°C per century.
Conclusion: Global land temperatures have been warming faster than U.S. land temperatures since 1895; since 1970; over the last 30 years; over the last 20 years; and over the last 10 years. Because the authors of the Fifth National Climate Assessment needed to convince mainstream journalists of the narrative that U.S. climate warming was the opposite of reality, they recklessly chose to ignore the official published NOAA temperature records. As a result, the FNCA's foundational climate statistic - "U.S. warming 60% faster than the world" - is a blatant fabrication that puts into question every other extreme claim the report makes.
Below is a sampling of major news sources on the FNCA report's very questionable findings that were published without any apparent fact checking. (links archived)
Additional global, regional & historical temperature charts.
Notes: Excel used for all calculations and plots. Source for NOAA's monthly global land temperature dataset; and source for NOAA's monthly U.S. national contiguous land temperature dataset. NOAA's national dataset Fahrenheit values were converted to Celsius in order to establish (i.e. calculate) Celsius anomalies from the 1901-2000 monthly baseline averages.