March 23, 2021 | David F. Coppedge

Climate Models Fail History Test

Can you trust a politically-sensitive science that doesn’t know history?

Believe it or not, the Sahara used to be green. A few thousand years ago, it was a land of forests and waterways, with abundant wildlife. Ground-penetrating radar can see riverbeds under the sand. Historical records recall the green Sahara as well. Climate models get that fact wrong when tested.

The world’s biggest desert was once green and filled with life.  (Image: Illustra Media)

Using the Mid‐Holocene “Greening” of the Sahara to Narrow Acceptable Ranges on Climate Model Parameters (Geophysical Research Letters).  In February 2021, Hopcroft, Valdez and Ingram decided to see if current climate models can account for the greening of the Sahara. What they discovered should be of great concern to those who think climate models are accurate. They say the greening period was from 11,000 to 4,000 years ago. They also think the greening was due to Milankovitch orbital forcing, which is highly problematic (see 22 June 2018). But without quibbling about those details, look at the implications of failing the Green Sahara History Test:

During the early to mid‐Holocene vegetation expanded to cover much of the present‐day Sahara. Although driven by a well‐understood difference in the orbital configuration, general circulation models have generally failed to simulate the required rainfall increase. One possible explanation is the presence of systematic biases in the representations of atmospheric convection which might also impact future projections. We employ a Bayesian method to learn from an ensemble of present day and mid‐Holocene simulations that vary parameters in the convection, boundary layer and cloud schemes. The model can reproduce the “Green Sahara” rainfall if mixing between convective plumes and the environment is increased in the upper troposphere relative to lower down. This does not appreciably impact the present day simulation, meaning that the paleoclimate reconstructions are able to narrow constraints on suitable parameter ranges. This suggests that other uncertain components of climate models could be targeted in this way.

Despite their confidence that tweaking a few parameters can keep current climate projections intact, other statements in the open-access paper are less sanguine. Why do current models get the history test wrong?

One possible reason for this is that small scale features such as clouds and storms in the atmosphere must be approximated using parametrizations [sic]. These parametrizations are poorly constrained by available climate observations and they thus potentially introduce errors in predictions of past or future climate changes. In this work we show that the “greening” can be simulated accurately when the parametrizations are tuned not only with present day observed climate fields, but additionally with the past “green” Sahara state.

Sure; force the model to account for the green Sahara and all is well. Is that good science? Look at what they say lower down:

Structural limitations mean that many biases could be corrected by varying model parameters, and there are many more than the 11 we varied. Also, the existence of compensating errors means that tuning that improves one bias can actually exacerbate another. Despite this, in the REVopt case we significantly improved the mid‐Holocene precipitation in comparison with reconstructions, without affecting the simulation of the present day state. It is possible that with a more comprehensive list of parameters, for example, of the order of 20–50, some of these other biases may be reduced.

It’s only “possible” that other biases could be reduced, they say. But what if the other 39 or 40 parameters compound other errors instead of compensating for them? Can anyone have confidence that the remaining biases will not conspire to exacerbate the other biases? What does this admission do to model reliability? Remember, these models are what politicians rely on when they claim that they must “follow the science” in order to instigate draconian measures to to save the planet.

Clouds play major roles in climate but are the “missing piece” in climate models.

Other Climate News

Why Commercialization of Carbon Capture and Sequestration has Failed and How it Can Work (UC San Diego). This one gets political. Look how much money has been spent in goals to mitigate climate change. To what end?

In the last two decades, private industry and government have invested tens of billions of dollars to capture CO2 from dozens of industrial and power plant sources. Despite the extensive support, these projects have largely failed. In fact, 80 percent of projects that seek to commercialize carbon capture and sequestration technology have ended in failure.

To make companies cooperate, the UC San Diego geniuses think governments need to add more carrots and sticks. Don’t let businesses read the paper (above) that says the models are full of biases.

They identified 12 possible determinants of project outcomes, which are technological readiness, credibility of incentives, financial credibility, cost, regulatory challenges, burden of CO2 removal, industrial stakeholder opposition, public opposition, population proximity, employment impact, plant location, and the host state’s appetite for fossil infrastructure development.

Dry ice, the unsung hero of the COVID-19 vaccine rollout, explained ( This article might be jokingly renamed, “Vaccines cause global warming.” Author Tom Avril doesn’t say that, of course; he assures the world that there’s nothing to see here, even though dry ice production (frozen CO2) has increased 5% in order to keep vaccines cold.

Carbon dioxide also is a greenhouse gas, meaning it plays a role in climate change, but that’s a subject for another day. And dry ice doesn’t really contribute to the problem, since it is made from CO2 that is being produced anyway.

CO2 doesn’t just ‘play a role’ in climate change (aka global warming); it is the main culprit. That’s the reason for carbon taxes, carbon sequestration, and carbon caps. Individuals are told to reduce their carbon footprints. It’s the reason carbon dioxide must be buried in the ocean, global warmists insist. That 0.04% of our atmosphere is going to kill the planet unless we get its numbers down.

Given the hatred of CO2 in the media, isn’t it rather odd that humans manufacture 35,000 tons of it a day, of which 16% is made into dry ice that eventually sublimates into the atmosphere. Where is all that dry ice going that is used to keep vaccines cold? CO2 is also used to keep many frozen goods from perishing as they are trucked to the supermarket. It’s used to make ice cream. It’s used to remove graffiti from walls, Avril says. It’s even used by theaters to create stage fog. Worst of all, people exhale it! Auggghhh!

You’re Not Gonna Believe This

Aircraft contrails are a climate menace. Can we rid the sky of them? (New Scientist). This article might be a kind of ‘warmist chemtrail conspiracy’ story. Global warmists are concerned about jet contrails in the sky not because they fear the government is spraying chemicals on the public, but rather that soot from jet exhaust increases the formation of contrails that trap solar heat. Natural cirrus clouds do that, too, but NS complains that this is an artificial addition: contrails are like man-made cirrus clouds: “The wispy cloud trails left by aircraft cause more warming than the carbon emissions from their fuel.” Will this bother the consciences of those flying to Paris for climate conferences? “That may come as an unwelcome surprise to climate conscious travellers paying to offset the carbon emissions from their flights because such offsets overlook the impact of contrails.

Twice as much carbon flowing from land to ocean than previously thought ( Here’s another 200% error just reported: carbon flowing into the ocean is double what they used to believe. They don’t know yet how much is captured by the ocean sediments and how much is outgassed back to the atmosphere. It’s possible it just represents a natural part of the carbon cycle – nothing to worry about. These are the “experts” that governments trust, but what they don’t know seems considerable.

With drop in LA’s vehicular aerosol pollution, plants emerge as major source (UC Berkeley News). Just when everyone thought LA’s smog-reduction program was a smashing success, climate worriers say that trees cause global warming. Trees emit volatile compounds that can build up in the atmosphere, Robert Sanders says. Who knows what effect these particulates will have on global warming? One redeeming feature in the report is its belated exoneration of Ronald Reagan, who was laughed at mercilessly in 1981 for claiming that “Trees cause more pollution than automobiles do.” That was then; this is now. “President Ronald Reagan was partially correct,” Sanders admits. “At the time, scientists were learning about the role of forests surrounding Atlanta in causing that city’s air pollution.” The question now is, have scientists and reporters learned their lesson?

Carbon pawprint: is man’s best friend the planet’s enemy? ( Now they want to blame the family dog for global warming. Pets do not drive cars, but some mad scientists are claiming that the family dog may be “as bad for the planet as a gas-guzzling SUV.” The idea is that human desire for meat also promotes the industry for pet food. They make the same claim about cat food, and urge people to participate in carbon mitigation by obtaining more eco-friendly pets, like a bird, a hamster, a lizard or – wait for it – a “big spider.” If that thought makes you scream, try this cute little furry jumping spider shown on; looks cuddly, doesn’t it? And it’s only 4 millimeters long. Either that, or teach your dog or cat to go vegan. Good luck with that. Whatever happened to the pet rock craze? Its time has come.

 If climate science can’t even get the greening Sahara right, which was just a few thousands of years ago, how can one trust Darwinists get millions and billions of years right? We must “follow the science,” they say. No one must be skeptical. If you don’t agree with the consensus, you are a pseudoscientist or a conspiracy theorist. You must be canceled. Your social media accounts must be suspended, and you become a non-person.

We’re just telling you what the insider experts themselves are saying. You decide.



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