Die kalte Sonne website here has a guest post by Frank Bosse. I’ve translated and condensed it in English:
Troposphere and Sea Surface Temperature: 18 Years With No Trend
Guest post by Frank Bosse
There’s a heated debate going on concerning the trend of non-rising global temperatures CRU (HadCRUT4) for the last 16 years.
In 2011, a paper authored by Ben Santer and colleagues described that at least a 17-year trend is needed to identify the human impact on the mean temperature of the troposphere. The paper’s summary:
Our results show that temperature records of at least 17 years in length are required for identifying human effects on global-mean tropospheric temperature.”
This mainly referred to the Temperature Lower Troposphere (TLT):
This brings us to the issue of auto-correlation, principally how long and how often must the temperature be measured before a significant trend can be established with a sufficient level of confidence. Is the trend positive (and not random) and can it be traced back to a real warming? If it can, then the trend is said to be significant. In statistics we can say that a 95% confidence interval means that the trend must be 95% real trend, and only 5% random.
There are statistical tests available to show whether the measurements are strongly dependent on each other or not. The dependency of a measured value on the previous value is called auto-correlation.
In the paper named above, the limit is 17 years. But to be sure, we want to look at the past 18 years, i.e. the months from September 1994 until August 2012, which means 216 measurements. We calculate a 6-month mean value and look to see whether the trend is significant at the 95% confidence level. If that is the case, then both limit values of the trend increase must be positive. Is this the case?
The mean trend (black) is in fact positive, but it is not significant. The lower (blue) is negative. Thus it is shown when considering auto-correlation that the condition of Santer in his paper hasn’t existed since September, 1994. The temperature of the troposphere has not significantly risen over the last 18 years.
And there’s more. We examine the temperature of the sea surface since 1995, see here:
We presume that the temperature will persist at its (high) August 2012 level until December because of an announced El Nino (one that will not show up, but we don’t want to be accused of cherry-picking). Here the trend is 0.067 °C per decade, but it is not significantly positive at the 95% confidence level when one uses the annual mean values. Also the temperatures of the entire sea surface have not risen significantly over the last 18 years.
What does it all mean? Does man no longer have an impact on the temperatures of the troposphere and sea surface temperature? With certainty man does have an impact, as he has been emitting CO2. The concentration of CO2 in the atmosphere since 1995 has risen from 359 ppm to 397 ppm. According to IPCC models, tropospheric and sea surface temperatures should have increased significantly, but they haven’t. Here natural variability, e.g. ENSO, has also played a role. So can CO2 sensitivity be as much as assumed? 3.2°K per doubling of CO2 concentration?
Two contributions from the recent past contradict this: one comes from an examination of the radiation budget when Pinatubo erupted in 1991: a value of 1.4°K, the other comes from an evaluation of the global temperatures and the heat content of the upper 2000 m of water in the ocean (OHC): 1.7°K.
What is the most probable? 3.2°K CO2 climate sensitivity as estimated by the IPCC or 1.6K?
The fulfillment of the famous Santer Postulate for the temperatures of the troposphere and sea surface temperature speaks for the latter estimate. This leads us to the final assumption made in Lüning’s and Vahrenholt’s book “Die kalte Sonne”: The man-made share of warming likely is only half as much as what is assumed by the IPCC.
Note: That the warming is only half-caused by man is also claimed by German climate scientist Mojib Latif, who repeatedly attacked Vahrenholt and Lüning – just because they agree with his claim!