It has been widely noted across the entire blogosphere (and even the mainstream press outlets) that the IPCC AR5 summary report avoided the very uncomfortable truth that modern global warming has gone literally AWOL over the last 15+ years, and the associated IPCC climate models' spectacular failure to predict this non-global warming environment.
Understandably, the IPCC's political bureaucrats don't want to shine a light on their previously claimed "irreversible", "incontrovertible", "irrefutable", "unequivocal", "indisputable", "relentless", "dangerous" and "accelerating" CO2-warming that has turned into the unprecedented modern "hiatus".
The IPCC's lack of analysis regarding this 15-year "pause" was replaced with an attempt to obscure the current temperature reality with a laughable decadal analysis. 'C3' previously commented on the lameness of the IPCC's decadal 'smoke and mirrors' as did others (here, here, here).
The IPCC's decadal approach to relied on 'decadal means.' There are other approaches, including analyzing decade-end temperatures, decadal-trends as shown here or by examining the moving 10-year (decadal) periods.
(click on image to enlarge, sources for HC4 and CO2 data)
In this article, we look at the moving decadal spans since January 1, 1950 through August 2013 (the IPCC states that at least 50% of the warming is due to anthropogenic reasons over this 764-month period) versus the previous 764-month period (May 1, 1886 through December 1949) that the IPCC infers was dominated by natural climate forces.
From the two 764-month periods, it is possible to generate 645 moving 10-year average data points for both the modern era and the earlier 20th century period. The above two charts plot the moing decadal data points for both periods.
Per an examination of the 10-year moving averages for each time span, there are several points of interest, including:
•Despite the vast differences between the two period's absolute CO2 levels and growth rates, the warming characteristics of the two periods are more alike than different.
•These ten-year curves, and their respective 2nd order fits, visually share similar characteristics such that one could easily and safely conclude that the modern warming was simply a repeat of the earlier period's warming (note: recall, the IPCC states that the earlier warming was not due to anthropogenic reasons).
•The 10-year moving average curves reveal that both the earlier and modern periods experienced a cooling phase, then a significant warming phase prior to leveling out to a plateau (a 'hiatus') close to the end.
•The warming phase during the modern era was 417 months in duration; the early 20th century period had a warming phase of 397 months (only a 20-month difference).
•Based on 10-year moving averages, the earlier warming period produced a +0.75°C per century trend, which is not that terribly different than the modern warming of a 1.16°C per century trend.
•If modern warming were to revert to the earlier warming trend (after the "hiatus"), by year 2100AD global temperatures would increase by +0.65°C. In contrast, a continuation of the modern warming trend would produce an increase of +0.99°C, just one-third of a degree greater.
•When comparing the differences between the lowest to highest 10-year average temperature for each warming period, the modern change was less than one-tenth degree greater.
•The modern era's CO2 level absolute increase and linear trend growth were both approximately 5 times greater than the earlier periods respective values.
•Yet the earlier period's degree change per ppm was over 3 times greater than that experienced during the modern warming.
Obviously, this type of decadal analysis reveals an abundance of similarities shared by the two 20th century warming periods. In fact, this analysis makes it clear that over 50% of the modern global warming could be a direct result of the same natural climate forces that warmed the world prior to the 1950s.
This analysis also directly contradicts the IPCC's anti-science terminology ("irreversible", "incontrovertible", "irrefutable", "unequivocal", "indisputable", "relentless", "dangerous", "accelerating" and "unprecedented") used to describe the modern era of warming. Simply put, none of these descriptors are accurate - they are without any empirical scientific merit.
Unsaid in this analysis (and the IPCC's) is that portion of modern warming associated with anthropogenic factors is not exclusively due to CO2 and other greenhouse gases. Other anthropogenic forces causing increases includes a wide spectrum of land-use issues, black soot pollution, 'slash and burn' deforestation practices, the urban heat island (UHI) effect, poorly sited climate/weather stations, the egregious fabrication of modern global warming by governmental climate agencies and other factors.
Finally, this decadal analysis reveals the absolute known physics of CO2-induced warming: per the actual physics, it has been established that the climate response (i.e. global temperatures) is logarithmic. This means that the earlier rises of atmospheric levels (ppm) of CO2 have a much greater impact on the climate than the later CO2 increases (ppm).
As the charts detail, the CO2 impact on temperature degrees was 3 times greater during the early warming than the modern warming (+0.23°C per CO2 ppm versus +0.007°C per CO2 ppm). This confirms the actual climate science physics, while at the same time pretty much demolishing the fears of the totally speculative, failed and unsubstantiated "positive feedback" physics that alarmists continue to rely on.
Empirical-based science rules, no?