I read a recent article at the CO2 Science website entitled “One Hundred Years of Global Temperature Change: 1906-2005.” The article discusses the conclusions of a study made to try and determine if 20th century warming is the result of an anthropomorphic-related temperature increase.
Working with 2249 globally-distributed monthly temperature records covering the period 1906-2005, which they obtained from NASA’s Goddard Institute for Space Studies, the authors evaluated “to what extent the temperature rise in the past 100 years was a trend or a natural fluctuation.”
What was learned:
Ludecke et al. report that “the mean of all stations shows 0.58°C global warming from 1906 to 2005,” but they say that “if we consider only those stations with a population of under 1000 and below 800 meters above sea level, this figure drops to 0.41°C.” In addition, they note that “about a quarter of all records show falling temperatures,” which in itself, in their words, “is an indication that the observed temperature series are predominantly natural fluctuations,” where the word natural means that “we do not have within a defined confidence interval a definitely positive anthropogenic contribution.” And continuing to explore this aspect of their analysis, they evaluated – with a confidence interval of 95% – the probability that the observed global warming from 1906 to 2005 was a natural fluctuation, finding that probability to lie “between 40% and 70%, depending on the station’s characteristics,” while “for the period 1906 to 1955 the probabilities are arranged between 80% and 90% and for 1956 to 2005 between 60% and 70%.”
It’s interesting that this study went to the trouble to factor out the Urban Heat Island effect by removing densely populated areas from the results. Of course, the alarmists try and capitalize on the UHI effect to support their erroneous beliefs.
