The main sets I use for the Blended Temperature set have finally updated for the month of January 2011. The historical behavior for the month of January is very different than the one presented by the theory of Global Warming. There are many claims that the Earth is warming more in Dec-Feb months, but when the monthly data is looked at by itself there is a distinct difference in the results. Especially if the actual monthly data is looked at. January is a very good example of a month that shows a very different picture of the past 160 years than the warmists paint.
The warmest month in the blended set was January of 1863. The monthly anomaly for that month was 0.751 °C. In that period of time there were the warmest and the coldest Januaries that have been recorded. The coldest was in 1850 with an anomaly of -1.646 °C. That is a difference of more than 2 °C slightly more than 10 years apart. Large variations in January temperatures are normal. Certainly part of this could be the very limited data that was available globally during this period of time, but since we are told that the data is good and should be trusted by the warmist consensus, I will go ahead and use it.
Here is what the past 160 years look like when shown by year. The moving average is a 9 year average.
There are three periods when there were months as warm as they currently are. In the 1850-1880 period, 1930-1950 and finally from about 1995-now. It is no surprise that there periods also coincide with warm phases of the Pacific and Atlantic ocean oscillations. The biggest difference in the first period was that there were also very cold months intermixed in with the warm ones. The warmest and the coldest Januaries took place back then. There have been less truly frigid months in the past 100 years, but the warmest months are no different now than they were 160 years ago. Since the warmists say that the world was better then than now, I suppose that they want winters that are much colder than the one the world experienced this year. The recent claim that 2011’s difficult January was caused by global warming looks very weak in comparison to the actual historical data, regardless of what Al Gore says. All around a review of the month of January is bad for the idea of global warming.
From a statistical point of view the average anomaly for the past 160 years is -0.124 °C. The standard deviation is 0.377 °C. So any temperature between -0.879 and 0.630 °C is within 2 standard deviations. In a true process control situation 3-sigma is used, but since climate generally uses 2-sigma I will stick with that standard. By that standard only two years are 2-sigma warm. 2007 and the all time warmest year which is 1863. There were many 2-sigma cold years before 1880 though. So the variation of cold Januaries is by far the most significant change.
More interesting is that the 60 year period when CO2 was increasing from the 1925-1985 time frame there is no warming at all in the data. The trend is perfectly flat for that entire period. CO2 climbed from what is considered natural to 340 ppm in that period of time that January had no trend. Some would argue that it takes time for CO2 to have an effect, but that isn’t how radiative heat transfer works.
Only if the past 20 years are included does any significant trend show up in the data. Perhaps even less shocking is that the satellite data does not show the same trend that the other data sets do. So in the period that actually shows warming, the satellite data is available and doesn’t show the same results. The warming is primarily showing up in the station data sets. This is precisely why so many people are skeptics. The data just isn’t there to support that significant change has happened in the Earth’s climate. What is visible is natural variation. That there is less variation now than there was previously is easily explained by the limitations of data from 150 years ago.
From a historical perspective there is no evidence that the month of January warmer now than it was 150 years ago. A chart will show that the average is warmer, but only because the older data shows very cold months back then. That the past 4 years appear to be reversing the warming is all the more reason to be skeptical about the theory of global warming.
That this is the third period of “warmer” months in the past 160 years is another reason to consider that there is real and natural variation in the Earth’s climate. Since the warm Januaries in the past two periods could not have been caused by CO2 emissions there is strong evidence that natural variation is a very important part of the Earth’s climate. Saying otherwise is denying reality.