Think we can model climate? Clouds in the way! – Watts Up With That?

By Ron Barby

I’ve looked at climate change from both sides, and I’ve found common ground between proponents and skeptics of the belief that climate change is largely man-made. When it comes to global temperature projections, prominent experts on both sides agree that a dominant variable cannot be simulated in computer models because clouds get in the way.

Among the proponents is Dr. Bjorn Stevens, a contributing author for Assessment Report 5 (2014) of the Intergovernmental Panel on Climate Change (IPCC). Dr. Stevens is also a director at the Max Planck Institute of Meteorology, Hamburg, Germany and a cloud expert. In a recent time interview he acknowledges that the contribution of clouds to global warming is overestimated in the IPCC’s “Climate Change 2021: The Physical Science Basis”.

“Clouds are con artists,” he said, referring to their complexity. However, he said, many scientists use oversimplified cloud representations in modeling “as a guide because they are easier to simulate. This makes climate models less accurate.”

On the skeptical side is Dr. Richard S. Lindzen, former lead author of IPCC Assessment Report 3 and now a vocal critic of the IPCC. In a recent podcast, the interviewer noted that Lindzen has published enough research papers to earn her 80 Ph. (Lindzen humbly declines the compliment.)

Lindzen, professor emeritus of Atmospheric Science at the Massachusetts Institute of Technology, shown that the IPCC models are based on hypothesis that water vapor and clouds amplify the greenhouse gas effect of CO₂ to achieve forecasts of catastrophic global warming. The IPCC theory is that the warmer atmosphere will have a higher water vapor content – itself a greenhouse gas – further increasing the warming caused by CO₂. Without this amplified “positive feedback” effect, the models are still wrong for a variety of reasons, but they no longer predict “catastrophic” warming.

Dr. Stevens, who once declared that global warming is a “big deal”, agrees that rising clouds do not increase global warming: “Water-rich low-lying clouds over the ocean Tropical oceans have the greatest cooling effect, and low-altitude ice clouds have the strongest warming effect. Overall, the cooling effect is greater.” That’s called “negative feedback”.

Dr. Lindzen argues that the global average temperature is controlled by the polar regions. Temperatures in the tropics are relatively stable over long periods of time while the polar regions have considerable variation. In other words, a small change in the global average temperature is the result of a large change in the temperature of the poles. The stability of tropical temperatures suggests that rising clouds provide negative feedback during periods of global warming. Instead of exacerbating the global warming effect of CO₂clouds reduce it.

Lindzen proposes a mechanism that produces a larger negative feedback: High-altitude cirrus clouds (low-water ice clouds that cause Dr. Stevens’ warming) control how much heat is released time. As the air beneath these clouds warms, the cirrus clouds dissipate and allow more energy to radiate into space. He called this Iris effect.

Nature is driven by negative feedback, not positive feedback. French chemist Henry Louis Le Chatelier expressed this in Le Chatelier’s principle: A system in dynamic equilibrium (in this case, climate) is disturbed by changing conditions (in this case, in this case) This is the concentration of CO₂), then the equilibrium shifts to resist the change. Negative feedback occurs because when one variable changes, the other variables respond in a way that compensates for the change.

We cannot model the cloud. The IPCC acknowledges this. However, its predictive models are based on assumptions that CO . amplified clouds₂ warming, without its temperature forecast is benign (it’s a strike).

IPCC forecasts are based on cloud models presented by renowned cloud experts on both sides—advocates of And skeptics of the concept of anthropogenic climate change. A recognized cloud expert and IPCC author (Dr. Stevens) claims that clouds cool overall, not heat (hit two).

And finally, the observed stabilization of tropical temperatures argues that rising clouds provide an even greater negative feedback to CO._2, and a cloud expert who has done enough research for 80 PhDs (Dr. Lindzen) has an idea of ​​how that happens (hit three).

Clouds do not amplify global warming; they promote global cooling. That should be enough to convince this climate heretic that the IPCC projections are not a “red light” for humanity and reject the frantic effort to eliminate CO.₂ from our economies.

The IPCC forecasters overstated warming because somehow they still really don’t understand the clouds.

This commentary was first published at Real clear marketApril 7, 2023, and can be accessed This.

Ron Barmby, a professional engineer with a master’s degree in geosciences, has 40 years of experience in the energy industry in 40 countries and 5 continents. He is the author of “Sunlight on climate change: A heretical guide to global climate hysteria” and proud to be a member of CO₂ Union, Arlington, Virginia.

card: clouds, Richard Lindzen, IPCC, Ron Barmby, Intergovernmental Panel on Climate Change, Bjorn Stevens, Iris effect, Ronald Barmby