New study shows that the climate models get it very wrong on cloud coverage

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.

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Proof that the recent slowdown is statistically significant (correcting for autocorrelation)

Watts Up With That?

Guest essay by Sheldon Walker

Introduction

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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Sea level rise acceleration (or not): Part I – Introduction

Climate Etc.

by Judith Curry

Introduction and context for a new Climate Etc. series on sea level rise.

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Mass gains of the Antarctic ice sheet exceed losses

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.

urn_cambridge.org_id_binary-alt_20170926044755-12677-optimisedImage-S0022143000200221_fig1g

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.

New Study Predicts Global Cooling until 2050

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. 

TOASCJ-11-44_F2

Polar Bears, Inadequate data and Statistical Lipstick

Climate Audit

LipStbear

A recent paper Internet Blogs, Polar Bears, and Climate-Change Denial by Proxy by JEFFREY A. HARVEY and 13 others has been creating somewhat of a stir in the blogosphere. The paper’s abstract purports to achieve the following:

Increasing surface temperatures, Arctic sea-ice loss, and other evidence of anthropogenic global warming (AGW) are acknowledged by every major scientific organization in the world. However, there is a wide gap between this broad scientific consensus and public opinion. Internet blogs have strongly contributed to this consensus gap by fomenting misunderstandings of AGW causes and consequences. Polar bears (Ursus maritimus) have become a “poster species” for AGW, making them a target of those denying AGW evidence. *Here, focusing on Arctic sea ice and polar bears, we show that blogs that deny or downplay AGW disregard the overwhelming scientific evidence of Arctic sea-ice loss and polar bear vulnerability.* By denying the impacts of AGW…

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Is climate change the culprit causing California’s wildfires?

Once again…climate change is not causing wildfires. Wildfires are down dramatically from the 1930s, and the small recent increase is due to forest management policies NOT climate change.

Climate Etc.

by Larry Kummer

We’re told that climate change caused or intensified California’s wildfires — and that such fires are getting worse. As usual for such scary stories, these claims are only weakly supported by science — except for the ones that are outright fabrications.

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