Reblogged from NoTricksZone
By Dr. Sebastian Lüning and Prof. Fritz Vahrenholt
(German text translated/edited by P Gosselin)
Droughts increase the risk of forest fires; that’s logical. However it is false to reflexively assign every forest fire to climate change. There have always been droughts and forest fires. Anyone wishing to shift the blame over to climate change first has to show that the trend has already deviated from the range of natural variability. For many, that is simply too much work.
2004 – 2014 burn acreage trend is falling. Chart source: Tony Heller.
A new study by Yin and Porporato published on December 22 in Nature Communications, concludes that “most GCMs present considerable discrepancies in the standard deviation (σ) and centroid (c) of cloud cycles.” The authors conclude that the systematic error in the models leads to an over estimate of radiative energy from the sun of 1 to 2 watts per square meter which is roughly half of the 3.7 watts additional radiative forcing attributed to all the CO2 produced since the beginning of the industrial age.
Guest essay by Sheldon Walker
In my last article I attempted to present evidence that the recent slowdown was statistically significant (at the 99% confidence level).
Some people raised objections to my results, because my regressions did not account for autocorrelation in the data. In response to these objections, I have repeated my analysis using the AR1 model to account for autocorrelation.
By definition, the warming rate during a slowdown must be less than the warming rate at some other time. But what “other time” should be used. In theory, if the warming rate dropped from high to average, then that would be a slowdown. That is not the definition that I am going to use. My definition of a slowdown is when the warming rate decreases to below the average warming rate. But there is an important second condition. It is only considered to be a slowdown when…
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So contrary to what you read in the popular press all the time, for example today in the Boston Globe, the Antarctic ice sheet is growing not shrinking and therefore contributing to the lowering, not raising, of global sea level. In a paper published online this year in the Journal of Glaciology, Zwally, Li, et al show that the mass gains from 2003-2008 reduced global sea level rise by .23 mm per year.
Fig. 1. The principal processes affecting the mass balance and dynamics of the ice sheets are ice mass input from snowfall with losses from sublimation and drifting. Surface melting on the grounded ice of Antarctica is very small, and subject to refreezing in the firn. Interaction with the ocean occurs at the undersides of the floating ice shelves and glacier tongues, and consequent changes in thickness affect the rate of ice flow from the grounded ice.
A new study by Horst-Joachim Lüdecke and Carl-Otto Weiss published in The Open Atmospheric Science Journal earlier this year predicts that global temperatures will cool for the next 30 years. The study uses a large number of proxy data sets to create a global temperature mean they call G7 spanning the last 2000 years. Their harmonic analysis of G7 identifies three significant cycles with periods of ~1000, ~460, and ~190 years. Using these three components alone shows a very strong Pearson correlation of .84 with the 31-year running average of G7. And the three-component curve exhibits all the major temperature extremes of the last 2000 years including the Roman, Medieval, and the current warm periods, as well as the 1450 minimum of the Little Ice Age. The paper also provides new proof that the ~190-year cycle is caused by the sun. The three-component temperature curve further predicts that global temperature will drop from the present to 2050, followed by a slight rise from 2050 to 2130, and a further drop from 2130 to 2200.
Fig. (2) (Color online) Left panels: Temperature records [oC] as anomalies around the mean, of Chr, Bün, McK, Vill-N, Vill-S, Pet, and the composite global record G7. The record of common production rate PC of the cosmogenic nuclides 14C and 10Be, Stei, is depicted in panel row 4, column 2. Right panels: Pertinent Fourier spectra with false-alarm lines of 95% (green) and 99% (red). The period of the strongest peak (generally ~190 year) is given.