German Scientists: IPCC Climate Models “Out Of Control”…”Exclusion Of Critics A Historic Mistake”

New IPCC report under doubt: models out-of-control and a new hockey stick

By Die kalte Sonne
[German text translated/edited by P Gosselin]

IPCC authors “politically handpicked”

The IPCC climate status report serves as an important reference for climate policy and public discussion. However, very few people are aware that the authors of the report are politically hand-picked. Although anyone can apply as an author to the national IPCC committees, the selection process is not transparent behind closed doors. The IPCC had to take a lot of criticism for this, but persists in its exclusionary line.

Thus critics have no chance to participate in the climate referee reports.

Huge uncertainty persists

The 6th IPCC report (Assessment Report 6, AR6) is currently being prepared. The first round of reviews has been completed and work on the second draft is in full swing. One of the central topics of each report is the warming effect of CO2, so-called CO2 climate sensitivity. Hardly anything has changed in the last 30 years. The value is still very poorly known and ranges from “we have to keep an eye on it” to “catastrophically strong warming”. In numbers: 1.5°C to 4.5°C warming per CO2 doubling.

Climate sensitivity in the lower range

In recent years it has become increasingly clear that the value is probably located in the lower half of the IPCC range. So it will be interesting to see how the AR6 deals with this. But don’t hold your breath because the IPCC seems to be true to its alarmist line, despite many published references to a lower warming by CO2.

Paul Voosen spoke on this in Science on 16 April 2019. The IPCC modelers had “improved” some processes in their climate simulations and were then quite surprised that the models suddenly ran much hotter than before. The CO2 climate sensitivity was now suddenly above the range previously thought possible, namely 5°C. The climate sensitivity of the models was suddenly much higher than before. Wow! The alarmists celebrated a feast of joy. However, more serious colleagues obviously threw sand in the alarmist gears and reported concerns.

Excerpt from Voosen’s article:

New climate models predict a warming surge

For nearly 40 years, the massive computer models used to simulate global climate have delivered a fairly consistent picture of how fast human carbon emissions might warm the world. But a host of global climate models developed for the United Nations’s next major assessment of global warming, due in 2021, are now showing a puzzling but undeniable trend. They are running hotter than they have in the past. Soon the world could be, too.

In earlier models, doubling atmospheric carbon dioxide (CO2) over preindustrial levels led models to predict somewhere between 2°C and 4.5°C of warming once the planet came into balance. But in at least eight of the next-generation models, produced by leading centers in the United States, the United Kingdom, Canada, and France, that “equilibrium climate sensitivity” has come in at 5°C or warmer. Modelers are struggling to identify which of their refinements explain this heightened sensitivity before the next assessment from the United Nations’s Intergovernmental Panel on Climate Change (IPCC). But the trend “is definitely real. There’s no question,” says Reto Knutti, a climate scientist at ETH Zurich in Switzerland. “Is that realistic or not? At this point, we don’t know.

[…] Many scientists are skeptical, pointing out that past climate changes recorded in ice cores and elsewhere don’t support the high climate sensitivity—nor does the pace of modern warming. The results so far are “not sufficient to convince me,” says Kate Marvel, a climate scientist at NASA’s Goddard Institute for Space Studies in New York City. In the effort to account for atmospheric components that are too small to directly simulate, like clouds, the new models could easily have strayed from reality, she says. “That’s always going to be a bumpy road.”

“Modelers at a loss”

CO2 climate sensitivity remains uncertain, modelers are at a loss. They had planned everything so beautifully for the AR6. Shortly before the end of the work, they quickly installed a new aerosolset, which then knocked everything down. The models suddenly showed hardly any warming for the 20th century. Ouch!

Perhaps the modelers were closer to the truth than they had thought, since there was now plenty of room for natural climatic factors, which they had previously set to zero as a precaution. So the models were completely changed again. And that finally led to the crazy high values of 5°C per CO2 doubling. Read for yourself:

Late in the model’s development cycle, however, the NCAR group incorporated an updated data set on emissions of aerosols
The aerosol data threw everything off when the model simulated the climate of the 20th century, it now showed hardly any warming. “It took us about a year to work that out,” says NCAR’s Andrew Gettelman, who helped lead the development of the model. But the aerosols may play a role in the higher sensitivity that the modelers now see, perhaps by affecting the thickness and extent of low ocean clouds. “We’re trying to understand if other [model developers] went through the same process,” Gettelman says.”

What consequences does the modeling chaos have for AR6?

In assessing how fast climate may change, the next IPCC report probably won’t lean as heavily on models as past reports did, says Thorsten Mauritsen, a climate scientist at Stockholm University and an IPCC author. It will look to other evidence as well, in particular a large study in preparation that will use ancient climates and observations of recent climate change to constrain sensitivity.”

“Total failure by climate models”

The AR6 will not be able to rely on the simulations and must therefore focus more on other areas of argumentation. But one thing is as certain as an “amen” in Church: The IPCC will claim that the temperature forecasts have become much more reliable than in the previous report, despite the total failure of the climate models. Although this makes no sense at all, it is politically necessary.

The way out: The new hockey stick curve that PAGES2k was able to publish in Nature Geoscience just in time, at the end of July 2019.


Figure: Global temperature reconstruction of the last 2000 years according to PAGES2k 2019.

If you thought Michael Mann’s hockey stick had suffered its final blow recently, then you are mistaken. Fact is: A new hockey stick was born in July 2019. Exactly to be used in the IPCC report. It is rumored that the curve was already included in the first draft of the AR6, although it wasn’t even released then. Mysterious.

MWP only 0.3°C warmer than Little Ice Age?

The Medieval Warm Period is ironed flat and is only 0.3°C warmer than the Little Ice Age. Wow. Are these the “ancient climates” which Voosen addresses in his contribution and form the new basis of argumentation?

PAGES2k shortcomings

A closer look at the PAGES2k database reveals a number of shortcomings. First, a large number of tree rings are used, of which only a few have been formally published as case studies. Example: The study uses tree rings from the French Maritime Alps, although a specialist publication on the region clearly advises against using such tree rings there as temperature proxies.

This is not an isolated case. If one goes through the PAGES2k database in detail, one finds a whole series of dubious practices, which were obviously overlooked by the peer review. Read about them in the following papers:

Lüning, S., L. Schulte, S. Garcés-Pastor, I. B. Danladi, M. Gałka (2019): The Medieval Climate Anomaly in the Mediterranean region. Paleoceanography and Paleoclimatology, doi: 10.1029/2019PA003734

Lüning, S., M. Gałka, F. Vahrenholt (2019): The Medieval Climate Anomaly in Antarctica. Palaeogeogr., Palaeoclimatol., Palaeoecol., doi: 10.1016/j.palaeo.2019.109251

Lüning, S., M. Gałka, F. García-Rodríguez, F. Vahrenholt (2019): The Medieval Climate Anomaly in Oceania. Environmental Reviews, online Just-IN, doi: 10.1139/er-2019-0012

Lüning, S., M. Gałka, F. P. Bamonte, F. García-Rodríguez, F. Vahrenholt (2019): The Medieval Climate Anomaly in South America. Quaternary International, 508: 70-87. doi: 10.1016/j.quaint.2018.10.041.

Lüning, S., M. Gałka, F. Vahrenholt (2017): Warming and cooling: The Medieval Climate Anomaly in Africa and Arabia. Paleoceanography 32 (11): 1219-1235, doi: 10.1002/2017PA003237.

Authors ignoring important publications

It is also noticeable that the PAGES2k paper does not cite any of the recent publications on the medieval climate anomaly, although the medieval climate is one of the most important topics in the area of palaeoclimatology. At least two of the publications were accessible to PAGES2k authors (others appeared later), but were ignored for unknown reasons.  The papers were able to demonstrate medieval warming throughout the southern hemisphere. Some smaller areas also cooled at the same time, similar to today’s active temperature seesaws and coastal upwelling areas.

Questionable database

In the northern hemisphere the Medieval Warm Period was always known. In this respect, it is an absolute mystery as to how the new hockey stick fix came about, if not through a questionable database.

Conclusion: “climate chaos”

It is time for the IPCC to open up to criticism. The climate models are out of control, as are the paleo-climatic reconstructions. What remains is climate chaos. It is time for a scientifically sustainable new beginning in which criticism is seriously heard and integrated. The exclusion of critics was a historic mistake that is now falling on the IPCC’s feet.

via NoTricksZone

November 6, 2019 at 01:22PM


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