Monday, November 3, 2014

Thermidor in October?

While not as warm as September (Climate change? 10/18/14), October averaged slightly above normal for the month. According to the weather service:
 "The average temperature was 25.2 degrees which was 1.0 degrees above the normal. The average maximum temperature at the Fairbanks airport was 31.5 degrees which was 0.4 degrees below the normal maximum temperature. This ranked as the 40th coldest of 110 years of record. The average minimum temperature was 18.9 degrees which was 2.4 degrees above the normal minimum temperature. This ranked as the 51st warmest of 110 years of record."
 So while the max temps were below normal, the mins were well above. This is the same pattern noted for the Pacific northwest ( and was largely attributed by him to the PDO (Pacific Decadal Oscillation) rather than any influence from global warming. I found this kind of an odd conclusion, so googled it up. Found this comment on the PDO and global climate change: Is Pacific Decadal Oscillation the Smoking Gun? "The blogosphere is abuzz with the news that the Pacific Decadal Oscillation is reverting to a cool phase. Hot on the heels of this bombshell, a new climate model predicts a cooling North Atlantic Ocean will slow down global warming. This has led to speculation that man-made global warming is no match for natural cycles or even that Pacific Decadal Oscillation is responsible for most of the climate change over the past century including the warming since the mid-70's. The PDO is a climate phenomena found primarily in the North Pacific (as opposed to El NiƱo which affects mostly the tropical Pacific). It has two phases that it typically alternates between; usually staying in one phase for a significant period of time (as little as 10 and as much as 40 years). The phases of the PDO have been called warm phases (positive values) or cool phases (negative values). While we talk about a 20 to 30 year period, it is not very clear cut at all. In fact, an analysis of the frequency of the events does not produce much in the way of a firm period. While PDO does have some degree of correlation with short term variations in global temperature, the striking feature is the contrast in trends between PDO and global temperature. Obviously the PDO as an oscillation between positive and negative values shows no long term trend. In contrast, global temperature displays a long term warming trend. When the PDO last switched to a cool phase, global temperatures were about 0.4C cooler than currently. The long term warming trend indicates the total energy in the Earth's climate system is increasing. This is due to an energy imbalance - more energy is coming in than is going out. Various factors affect the Earth's energy balance. The total energy imbalance is expressed as net forcing, the sum of all the various forcings (eg - solar, aerosols, greenhouse gases, etc). When all forcings are included, net forcing shows good correlation with global temperatures. There is no single smoking gun. As our climate continues to absorb more energy than it emits, we can expect the long term warming trend to continue with short term fluctuations." 
So there you go, another opinion. Who's right? We'll probably know in a few more years, since the PDO is expected to enter a negative (cooler) phase. If global temperatures continue to rise, well, that's all folks.

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