Ben Santer: Climate Change Responsible for Hotter and Colder Weather

Guest essay by Eric Worrall

A new study by Ben Santer which claims that climate change is strengthening the heartbeat of the world’s climate, making winters colder and summers warmer.

Climate change strengthens Earth’s ‘heartbeat’ – and that’s bad news

By Chelsea Gohd, Staff Writer

Climate change is much more than rising temperatures and melting ice. In a new study, scientists from Lawrence Livermore National Laboratory (LLNL) and five other organizations show that human action significantly affects the seasonal temperature cycle in the troposphere, or lowest layer of Earth’s atmosphere — the layer that we live in where weather occurs.

In this new study, scientists examined seasonal temperature cycles in the troposphere and observed the profound impact humans are having on the atmosphere and our seasons. Most notably, the researchers found that because of carbon dioxide emissions, Earth’s seasonal “heartbeat,” or the contrast between hot summers and cold winters, is becoming stronger.

“Our results suggest that attribution studies with the changing seasonal cycle provide powerful and novel evidence for a significant human effect on Earth’s climate,” Benjamin Santer, LLNL climate scientist and lead author on the new work, said in a statement.

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The abstract of the study;

Human influence on the seasonal cycle of tropospheric temperature

Benjamin D. Santer, Stephen Po-Chedley, Mark D. Zelinka, Ivana Cvijanovic, Céline Bonfils, Paul J. Durack, Qiang Fu2, Jeffrey Kiehl, Carl Mears, Jeffrey Painter, Giuliana Pallotta, Susan Solomon, Frank J. Wentz, Cheng-Zhi Zou

We provide scientific evidence that a human-caused signal in the seasonal cycle of tropospheric temperature has emerged from the background noise of natural variability. Satellite data and the anthropogenic “fingerprint” predicted by climate models show common large-scale changes in geographical patterns of seasonal cycle amplitude. These common features include increases in amplitude at mid-latitudes in both hemispheres, amplitude decreases at high latitudes in the Southern Hemisphere, and small changes in the tropics. Simple physical mechanisms explain these features. The model fingerprint of seasonal cycle changes is identifiable with high statistical confidence in five out of six satellite temperature datasets. Our results suggest that attribution studies with the changing seasonal cycle provide powerful evidence for a significant human effect on Earth’s climate.

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Ben Santer is one of the more colourful climategate characters. He rose to fame after his email threat to beat the cr*p out of Pat Michaels was uncovered in the Climategate archive.

But there are plenty of other entertaining Santer emails. My personal favourite Santer climategate email is 1231257056.txt, in which he expresses outrage at having to release data and method to “scientific competitors”.

1. In my considered opinion, a very dangerous precedent is set if any derived quantity that we have calculated from primary data is subject to FOIA requests. At LLNL’s Program for Climate Model Diagnosis and Intercomparison (PCMDI), we have devoted years of effort to the calculation of derived quantities from climate model output. These derived quantities include synthetic MSU temperatures, ocean heat content changes, and so-called “cloud simulator” products suitable for comparison with actual satellite-based estimates of cloud type, altitude, and frequency. The intellectual investment in such calculations is substantial.

2. Mr. Smith asserts that “there is no valid intellectual property justification for withholding this data”. I believe this argument is incorrect. The synthetic MSU temperatures used in our IJoC paper – and the other examples of derived datasets mentioned above – are integral components of both PCMDI’s ongoing research, and of proposals we have submitted to funding agencies (DOE, NOAA, and NASA). Can any competitor simply request such datasets via the U.S. FOIA, before we have completed full scientific analysis of these datasets?

Source: Wikileaks

The latest Santer effort is interesting in the context of other climate predictions. Remember back when climate alarmists were predicting warmer winters and shorter snow seasons? The most impressive effort of the “warmer winter” cycle of predictions, in my opinion, is Dr. Trenberth’s prediction of warmer, shorter winters AND more snow in midwinter.

Does global warming mean more or less snow?

Kevin Trenberth
January 30, 2015 9.43pm AEDT

Going forward, in mid winter, climate change means that snowfalls will increase because the atmosphere can hold 4% more moisture for every 1°F increase in temperature. So as long as it does not warm above freezing, the result is a greater dump of snow.

In contrast, at the beginning and end of winter, it warms enough that it is more likely to rain, so the total winter snowfall does not increase. Observations of snow cover for the northern hemisphere indeed show slight increases in mid-winter (December-February) but huge losses in the spring (see snow cover figure above.) This is all part of a trend to much heavier precipitation in the United States (see figure below), especially in the northeast.

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Former NASA GISS director James Hansen went the other way with his scientific crystal ball, he produced a 2016 prediction of an imminent sharp drop in both Summer and Winter temperatures, followed by runaway warming.

Global temperature becomes an unreliable diagnostic of planetary condition as the ice melt rate increases. Global energy imbalance (Fig. 15b) is a more meaningful measure of planetary status as well as an estimate of the climate forcing change required to stabilize climate. Our calculated present energy imbalance of ∼ 0.8 W m−2 (Fig. 15b) is larger than the observed 0.58 ± 0.15 W m−2 during 2005–2010 (Hansen et al., 2011). The discrepancy is likely accounted for by excessive ocean heat uptake at low latitudes in our model, a problem related to the model’s slow surface response time (Fig. 4) that may be caused by excessive small-scale ocean mixing.

Large scale regional cooling occurs in the North Atlantic and Southern oceans by mid-century (Fig. 16) for 10-year doubling of freshwater injection. A 20-year doubling places similar cooling near the end of this century, 40 years ear- lier than in our prior simulations (Fig. 7), as the factor of 4 increase in current freshwater from Antarctica is a 40-year advance.

Cumulative North Atlantic freshwater forcing in sverdrup years (Sv years) is 0.2 Sv years in 2014, 2.4 Sv years in 2050, and 3.4Sv years (its maximum) prior to 2060 (Fig. S14). The critical issue is whether human-spurred ice sheet mass loss can be approximated as an exponential process during the next few decades. Such nonlinear behavior depends upon amplifying feedbacks, which, indeed, our climate simulations reveal in the Southern Ocean. …

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Lucky climate science is settled, otherwise all these apparently conflicting climate predictions might cause real confusion.

via Watts Up With That?

July 26, 2018 at 07:32PM

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