In January 2005, NOAA began recording temperatures at its newly built U.S. Climate Reference Network (USCRN). USCRN includes 114 pristinely maintained temperature stations spaced relatively uniformly across the lower 48 states. NOAA selected locations that were far away from urban and land-development impacts that might artificially taint temperature readings.
Prior to the USCRN going online, alarmists and skeptics sparred over the accuracy of reported temperature data. With most preexisting temperature stations located in or near urban settings that are subject to false temperature signals and create their own microclimates that change over time, government officials performed many often-controversial adjustments to the raw temperature data. Skeptics of an asserted climate crisis pointed out that most of the reported warming in the United States was non-existent in the raw temperature data, but was added to the record by government officials.
The USCRN has eliminated the need to rely on, and adjust the data from, outdated temperature stations.
What this new data show is that in the contiguous 48 states there has been a statistically insignificant amount of warming over the past 14 ½ years. Using NOAA's data, I created the following chart:
The green line is the best-fit trend line, and it shows that US temperatures have increased by about 0.6º F per decade, or roughly 0.06º per year. It's worth noting as well that US temperatures have been below average for most of the past year. This, at a time when headlines trumpet soaring global temperatures.
My intuition tells me that if US temperatures have barely increased at all over almost 15 years, then it is unlikely that global temperatures have increased by much more, if at all. After all, air does circulate around the globe. Climate skeptics have here one justification for being skeptical of those who warn that man-made global warming is an existential threat.