New Confirmation that Climate Models Overstate Atmospheric Warming

by R. McKitrick, Aug 17, 2021 in ClimateEtc


Two new peer-reviewed papers from independent teams confirm that climate models overstate atmospheric warming and the problem has gotten worse over time, not better. The papers are Mitchell et al. (2020) “The vertical profile of recent tropical temperature trends: Persistent model biases in the context of internal variability”  Environmental Research Letters, and McKitrick and Christy (2020) “Pervasive warming bias in CMIP6 tropospheric layers” Earth and Space Science. John and I didn’t know about the Mitchell team’s work until after their paper came out, and they likewise didn’t know about ours.

Mitchell et al. look at the surface, troposphere and stratosphere over the tropics (20N to 20S). John and I look at the tropical and global lower- and mid- troposphere.  Both papers test large samples of the latest generation (“Coupled Model Intercomparison Project version 6” or CMIP6) climate models, i.e. the ones being used for the next IPCC report, and compare model outputs to post-1979 observations. John and I were able to examine 38 models while Mitchell et al. looked at 48 models. The sheer number makes one wonder why so many are needed, if the science is settled. Both papers looked at “hindcasts,” which are reconstructions of recent historical temperatures in response to observed greenhouse gas emissions and other changes (e.g. aerosols and solar forcing). Across the two papers it emerges that the models overshoot historical warming from the near-surface through the upper troposphere, in the tropics and globally.

New Study: 2000-Year Precipitation Reconstructions Expose Climate Models Still Of Junk Grade

by Atwood et al., Aug 18, 2021 in NoTricksZone


A new study by Atwood et al (2021) published in the journal of Paleoceanography and Paleoclimatology found there’s “poor agreement” between precipitation reconstructions and model simulations over the past 2000 years. This means future projections made by current models are unreliable. 

 

Models and reconstructions don’t agree

These comprehensive reconstructions show that from 800 to 1000 CE there was a pronounced drying event relative from the eastern Pacific and parts of Mesoamerica.

Also the period “1400–1700 CE is marked by pronounced hydroclimate changes across the tropics, including dry and/or isotopically enriched conditions in South and East Asia, wet and/or isotopically depleted conditions in the central Andes and southern Amazon in South America, and fresher and/or isotopically depleted conditions in the Maritime Continent.”

The study’s abstract also notes how there’s a glaring disagreement between the simulations done by models and what the reconstructions show: “We find notable dissimilarities between the regional hydroclimate changes and global-scale and hemispheric-scale temperature reconstructions, indicating that more work needs to be done to understand the mechanisms of the widespread tropical hydroclimate changes during the LIA.”

Another Round Of Anti-Science From The IPCC (With A NEW Hockey Stick!)

by F. Menton, Aug 16, 2021 in ClimateChangeDispatch


What with the ongoing catastrophe in Afghanistan and the earthquake in Haiti, among other news, you may have failed to notice that the UN IPCC came out on Monday with substantial parts of its long-awaited Sixth Assessment Report on the state of the world’s climate.

This is the first such assessment issued by the IPCC since 2014. The most important piece is the so-called “Summary for Policymakers,” (SPM), a 41-page section that is the only part that anyone ever reads.

The IPCC attempts to cloak itself in the mantle of “science,” but its real mission is to attempt to scare the bejeezus out of everyone to get the world to cede more power to the UN.

Beginning with its Third Assessment Report in 2001, the lead technician for the IPCC to generate fear has been the iconic “hockey stick” graph, supposedly showing that world temperatures have suddenly shot up dramatically in the last 100 or so years, purportedly due to human influences.

The 2001 Third Assessment Report thus prominently featured the famous Hockey Stick graph, derived from the work of Michael Mann and other authors. Here is that graph from the 2001 Report:

 

 

McIntyre comments:

They took “hide the decline” to extremes that had never been contemplated by prior practitioners of this dark art. Rather than hiding the decline in the final product, they did so for individual trees: as explained in the underlying article, they excluded the “divergent portions” of individual trees that had the temerity to have decreasing growth in recent years. Even Briffa would never have contemplated such woke radical measures.

Decide on your desired conclusion and then just exclude any data that refuses to go along. This is the “science” on which our world leaders are off spending multiple trillions of taxpayer dollars.