UAH LT GLOBAL MEAN ANOMALIES & DECADAL TRENDS : 1979-2019

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THIS POST IS AN EVALUATION OF THE CLAIM IN THE YEAR 2019 THAT WE ARE ENTERING A COOLING PHASE.

1. UAH global mean lower troposphere temperature anomalies 1979-2019 and their decadal trends are presented in Figure 1 for the calendar months January to August. The thick red line traces temperature anomalies in the left frame and their decadal trends in a moving 10-year window in the right frame. In both frames, the dotted black line is a third order polynomial regression line. Curves in the third order regression line indicate changing trends in temperature in the left frame and changing trends in decadal trends in the right frame. Since no cooling trends are seen in these charts, we propose to examine the curvature of the third order polynomial for signs of “entering a cooling phase”.
2. If we were “entering a cooling phase” we would expect that the 3rd order polynomial line would show a dip at the inception of the cooling phase. No such dip in the 3rd order polynomial regression line is found in any of the 7 calendar months either in temperature anomalies or in decadal trends. In fact, the opposite is true for temperature anomalies in the calendar months of May and June where the polynomial shows an upward curve. In the 3rd order polynomial for decadal trends, the opposite is true for all seven calendar months where the time series ends in a rising trend.
3. These data do not support the repeated claims in various blogs and social media that we are “entering a cooling phase” or “entering a new ice age” or that the much anticipated solar grand minimum is already evident in the the surface temperature data. 
4. Regional data for ten regions are presented in GIF format below. Each GIF animation cycles through eight calendar months from January to August. The third order polynomial regression curve through the temperature data for each region is examined for a downward curvature at the end of time span close to 2019. Such curvature where found is interpreted as a harbinger of imminent cooling with the possible implication that “we are entering a cooling phase“.
5. In this examination of the GIF charts below, we find such curvatures in 12 of 77 possibilities (11 charts and 7 months). Two of the 12 positive results are found over Antarctica, where no global warming exists.  Even if the Antarctica data are included we get about 16% positive findings. The low percentage of positive results does not provide convincing evidence of an imminent cooling trend. The 16% positive curvature found can be explained as random variability as such curves are also seen elsewhere in the span earlier in time. It is noted that without Antarctica in the sample, the positive finding percentage drops to 14%. It is also noted that many of these regression curves end in an upward curvature. We conclude that these data do not provide convincing evidence that we have entered a cooling phase nor that we are entering a cooling phase.

COUNT OF ENDING DOWN-CURVES IN THE GIF CHARTS BELOW

GIF-D: GLOBAL LAND AND OCEAN

GIF-E: GLOBAL LAND

GIF-M: TROPICS

GIF-N: TROPICS LAND

GIF-P: NORTHERN EXTENT

GIF-Q: NORTHERN EXTENT LAND

GIF-S: SOUTHERN EXTENT

GIF-T: SOUTHERN EXTENT LAND

GIF-V: NORTH POLAR REGION

GIF-W: NORTHERN POLAR LAND

GIF-Y: SOUTH POLAR REGION