New ‘Consensus’ On Global Warming

By MICHAEL BASTASCH AND DR. RYAN MAUE – Re-Blogged From http://www.WattsUpWithThat.com

From the “well maybe there was a hiatus after all” walkback department. Even Mann is on board with this paper.

A scientific consensus has emerged among top mainstream climate scientists that “skeptics” or “lukewarmers” were not long ago derided for suggesting — there was a nearly two-decade long “hiatus” in global warming that climate models failed to accurately predict or replicate.A new paper, led by climate scientist Benjamin Santer, adds to the ever-expanding volume of “hiatus” literature embracing popular arguments advanced by skeptics, and even uses satellite temperature datasets to show reduced atmospheric warming.More importantly, the paper discusses the failure of climate models to predict or replicate the “slowdown” in early 21st century global temperatures, which was another oft-derided skeptic observation.

“In the early twenty-first century, satellite-derived tropospheric warming trends were generally smaller than trends estimated from a large multi-model ensemble,” reads the abstract of Santer’s paper, which was published Monday.

“Over most of the early twenty-first century, however, model tropospheric warming is substantially larger than observed,” reads the abstract, adding that “model overestimation of tropospheric warming in the early twenty-first century is partly due to systematic deficiencies in some of the post-2000 external forcings used in the model simulations.”

The paper caught some prominent critics of global climate models by surprise. Dr. Roger Pielke, Sr. tweeted “WOW!” after he read the abstract, which concedes “model tropospheric warming is substantially larger than observed” for most of the early 21st Century.

It’s more than a little shocking.

Santer recently co-authored a separate paper that purported to debunk statements EPA Administrator Scott Pruitt made that global warming had “leveled off.” But Santer’s paper only evaluated a selectively-edited and out-of-context portion of Pruitt’s statement by removing the term “hiatus.”

Moreover, climate scientists mocked Texas Republican Sen. Ted Cruz for talking about the global warming “hiatus” during a 2015 congressional hearing. Instead, activist scientists worked hard to airbrush the global warming slowdown from data records and advance media claim that it was a “myth.”

Santer and Carl Mears, who operate the Remote Sensing System satellite temperature dataset, authored a lengthy blog post in 2016 critical of Cruz’s contention there was an 18-year “hiatus” in warming that climate models didn’t predict.

They argued “examining one individual 18-year period is poor statistical practice, and of limited usefulness” when evaluating global warming.

“Don’t cherry-pick; look at all the evidence, not just the carefully selected evidence that supports a particular point of view,” Santers and Mears concluded.

Cruz’s hearing, of course, was the same year the National Oceanic and Atmospheric Administration (NOAA) released its “pause-busting” study. The study by lead author Tom Karl purported to eliminate the “hiatus” from the global surface temperature record by adjusting ocean data upwards to correct for “biases” in the data.

Democrats and environmentalists praised Karl’s work, which came out before the Obama administration unveiled its carbon dioxide regulations for power plants. Karl’s study also came out months before U.N. delegates hashed out the Paris agreement on climate change.

Karl’s study was “verified” in 2016 in a paper led by University of California-Berkeley climate scientist Zeke Hausfather, but even then there were lingering doubts among climate scientists.

Then, in early 2016, mainstream scientists admitted the climate model trends did not match observations — a coup for scientists like Patrick Michaels and Chip Knappenberger who have been pointing out flaws in model predictions for years.

John Christy, who collects satellite temperature data out of the University of Alabama-Huntsville, has testified before Congress on the failure of models to predict recent global warming.

Christy’s research has shown climate models show 2.5 times more warming in the bulk atmosphere than satellites and weather balloons have observed.

Now, he and Santer seem to be on the same page — the global warming “hiatus” is real and the models didn’t see it coming.

Santer’s paper argues the “hiatus” or “slowdown” in warming “has provided the scientific community with a valuable opportunity to advance understanding” of the climate system and how to model it.

What’s interesting, though, is Santer and his co-authors say their paper is “unlikely to reconcile the divergent schools of thought regarding the causes of differences between modeled and observed warming rates.”

In other words, the “uncertainty monster” is still a problem.

Reprinted via CC license from the Daily Caller News Foundation


The paper:

Causes of differences in model and satellite tropospheric warming rates

Benjamin D. Santer, John C. Fyfe, Giuliana Pallotta, Gregory M. Flato, Gerald A. Meehl, Matthew H. England, Ed Hawkins,
Michael E. Mann, Jeffrey F. Painter, Céline Bonfils, Ivana Cvijanovic, Carl Mears, Frank J. Wentz, Stephen Po-Chedley, Qiang Fu & Cheng-Zhi Zou

Abstract:

In the early twenty-first century, satellite-derived tropospheric warming trends were generally smaller than trends estimated from a large multi-model ensemble. Because observations and coupled model simulations do not have the same phasing of natural internal variability, such decadal differences in simulated and observed warming rates invariably occur. Here we analyse global-mean tropospheric temperatures from satellites and climate model simulations to examine whether warming rate differences over the satellite era can be explained by internal climate variability alone. We find that in the last two decades of the twentieth century, differences between modelled and observed tropospheric temperature trends are broadly consistent with internal variability. Over most of the early twenty-first century, however, model tropospheric warming is substantially larger than observed; warming rate differences are generally outside the range of trends arising from internal variability. The probability that multi-decadal internal variability fully explains the asymmetry between the late twentieth and early twenty-first century results is low (between zero and about 9%). It is also unlikely that this asymmetry is due to the combined effects of internal variability and a model error in climate sensitivity. We conclude that model overestimation of tropospheric warming in the early twenty-first century is partly due to systematic deficiencies in some of the post-2000 external forcings used in the model simulations.

https://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2973.html

 

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