The short version: NOAA's latest empirical evidence reveals that last 25 year period of global warming is not exceptional, nor unprecedented. Unexpectedly, NOAA's own evidence debunks their own global warming propaganda that they claim is fact.
Yes, the warming isn't exceptional but the irony certainly is.
NOAA is well known to aggressively push the misleading myth of a dangerous modern warming rate from CO2, and that this rapid warming can only be man-made, not a result of natural forces.
Yet its own temperature dataset proves past natural global warming rates of earlier periods are similar and as powerful.
And of course, NOAA always conveniently forgets about the substantial warming and climate change periods of the historical and geological past, which far exceed what NOAA has reported over the last 25 years.
Moving on to the long version of this analysis.....
(click on any chart to enlarge)
The long version: Unprecedented modern warming? A simple factcheck of NOAA's temp information proves otherwise.
With a multitude of politicos, greens, activists, pundits, journalists, and wildly uninformed celebrities jointly wringing their hands over 2015 being the hottest ever, it's beyond empirical doubt that the rate of the last 25 years of warming is not unique.
Yes, in a nutshell, it's warmer today than 25 years ago, but that's to be expected due to the 150+ year natural rebound in temperatures since the extreme cold of the Little Ice Age.
Putting aside the overused "hottest" adjective, does NOAA's empirical measurement prove that modern warming is significantly different than past natural warming? Have the last 25 years warmed a quantifiably greater amount than prior periods?
To the charts of NOAA empirical evidence to compare two 25-year climate periods of global warming.
Chart #1: For ease of comparison, the earlier 20th century monthly anomaly sub-dataset was offset so as to start at exactly the same anomaly point as the modern sub-dataset. When that is done, it is easier to visually match the similarities/differences of the two warming periods.
Despite their obvious differences in anomaly variation, these two distinct periods reflect similar outcomes over their respective 25 years. Even though the earlier 20th century period (1919 to 1943) experienced little in the way of consumer/industrial CO2 emissions, its monthly warming anomaly increase is almost a perfect match to the last 25 years, ending 2015.
The chart's fitted trends (2nd order polynomial) reveal the earlier period with a closing warming rate that is accelerating away from the modern fitted trend.
Chart #2 plots the calculated linear trends for both 25-year periods. The difference in 'per century' trends is rather minuscule, especially when considering the massive greenhouse gases released into the atmosphere since 1950. Objectively, the small trend increase of +0.40 degrees per century over the last 25 years is well within known natural variation.
Clearly, any warming impact of CO2 emissions has barely surpassed the per century trend produced by natural climatic forces from 1919-1943. Based on this empirical evidence, a robust conclusion would be that the CO2-centric AGW hypothesis is exceptionally insignificant.
Chart #3 compares the 5-year average warming for each period, using the same starting anomaly point. From the start, the ‘Modern’ 5-yr average rises much faster; but in an exceptional (dare we say "unprecedented") spurt, the ‘Earlier’ period 5-yr average closes the gap to a mere +0.03 degree warming difference at the end of 25 years.
Based on that tiny difference, one can fairly surmise that the huge CO2 emissions production over the last 25 years has not distinguished itself as climatically significant versus natural variation.
And it is interesting (and somewhat unexpected) that both the ‘Earlier’ and ‘Modern' periods had extended pauses, which are noted on the chart #3.
Chart #4 depicts the cumulative temperature change for the full 25 years (300 months) ending in 1943 and 2015; plus, their respective changes in CO2 levels. Per NOAA’s own empirical dataset, the earlier 20th century warming cumulative amount was actually greater than the modern era period ending in December 2015 — and remember, the December 2015 temperatures anomaly just had an incredible surge due to the current El Niño peak.
In conclusion, as stated in the first paragraph, modern warming over the last 25 years is not exceptional, nor unprecedented in spite of the gigantic accumulation of atmospheric CO2 emissions during the fossil fuel era. Based on real world climate and the actual evidence, simulated predictions of future dangerous warming remain without any scientific substance.
Notes: The period of 1919-1943 was chosen for analysis and comparison due to its visual pattern similarities to the last 25 years ending December 2015. Source of NOAA global temperature dataset; modern and historical CO2 datasets. Excel was used to plot and calculate trends/averages for all charts. Chart#1 had 1919-1943 anomaly plot adjusted to start at same anomaly point as 1991-2015 period; chart#2 linear trends are based off plots of chart#1; chart#3 uses 5-year averages calculated from each period's anomaly dataset and then the 1919-1943 5yr average was adjusted (i.e. offset) to start at same anomaly point as 1991-2015 5yr average; chart#4 cumulative differences calculation: the December 31, 1943 anomaly minus the December 31, 1918 anomaly and the December 31, 2015 anomaly minus the December 31, 1990 anomaly (both calculations covering a full 300 months).