World’s Lakes Show Global Temperature Standstill
06/28/2012 1 Comment
One thing I have learned in my study of climate change and the underlying statistics is that that selection of the starting and ending points in the data set can influence the out come. David Whitehouse has a perfect example from a poster session at the Taking the Temperature of the Earth Conference. Schneider et al 2012 took the temperature of 169 large inland lakes around the world using satellite IR photos.
According to their findings the surface temperatures of these water bodies have been “rapidly warming” with an average rate of 0.350 ± 0.11 deg C per decade for the period 1985–2010.
Here is the chart showing their findings.
When I first read the article I noted the flat top on the data starting about 1997/98 and just eyeballed the trend line from that point to the present, and I could not see any trend. Yes, there was warming, from 1980 1998, but none from that point on.
David Whitehouse at the Global Warming Policy Foundation also note that flat top and did some additional analysis, and here is his plot.
As you can see, the starting point makes a big difference in the outcome. From 1977 to 1997 the the Northern Hemisphere climate was being influenced by a warm phase PDO, which ended about 1998, which can account for some of the warming. The sun as still very active, and could have had some influence. Starting in 2000 solar cycle 23 started a slow decline. Historically a quite sun, with fewer sunspot, has resulted in a cooler earth.
Whitehouse concludes: No statistically significant trend post-1997. Since 1997 the data is best represented by a straight line of mean 0.21 deg with a large standard deviation of 0.95 deg. Below is the post-1997 portion of the researcher’s graph. It is easy to see that the trendline calculated from the 1985-2011 data does not fit this section of the data in which there is no trend.