Was, wenn sich das Klima selbst reguliert? | Wissenschaft ist entscheidend

Andy Kessler writes at WSJ Can the Climate Heal Itself?  Excerpts in italics with my bolds and added images.

Dissenters from the catastrophe consensus on warming are worth listening to.

Stop with all the existential-crisis talk. President Biden said, “Climate change is literally an existential threat to our nation and to the world.” Defense Secretary Lloyd Austin also talks about the “existential threat” of climate change. National security adviser Jake Sullivan identifies an “accelerating climate crisis” as one reason for a “new consensus” for government picking winners and losers in the economy. Be wary of those touting consensus.

But what if the entire premise is wrong? What if the Earth is self-healing? Before you hurl the “climate denier” invective at me, let’s think this through. Earth has been around for 4.5 billion years— living organisms for 3.7 billion. Surely, an enlightened engineer might think, the planet’s creator built in a mechanism to regulate heat, or we wouldn’t still be here to worry about it.

The theory of climate change is that excess carbon dioxide and methane trap the sun’s radiation in the atmosphere, and these man-made greenhouse gases reflect more of that heat back to Earth, warming the planet. Pretty simple. Eventually, we reach a tipping point when positive feedback loops form—less ice to reflect sunlight, warm oceans that can no longer absorb carbon dioxide—and then we fry, existentially. So lose those gas stoves and carbon spewing Suburbans.

But nothing is simple. What about negative feedback loops? Examples: human sweat and its cooling condensation or our irises dilating or constricting based on the amount of light coming in. Clouds, which can block the sun or trap its radiation, are rarely mentioned in climate talk.

Why? Because clouds are notoriously difficult to model in climate simulations. Steven Koonin, a New York University professor and author of “Unsettled,” tells me that today’s computing power can typically model the Earth’s atmosphere in grids 60 miles on a side. Pretty coarse. So, Mr. Koonin says, “the properties of clouds in climate models are often adjusted or ‘tuned’ to match observations.” Tuned!

Last month the coddling modelers at the United Nations’ World Meteorological Organization stated that “warming El Niño” and “human-induced climate change” mean there is a “66% likelihood that annual average global temperatures will exceed the threshold of 1.5 degrees Celsius above preindustrial levels by 2027.” Notice that El Niño is mentioned first.

Richard Lindzen, a professor at the Massachusetts Institute of Technology and lead author of an early Intergovernmental Panel on Climate Change report, told me, “Temperatures in the tropics remain relatively constant compared with changes in the tropics-to-pole temperatures. The tropics-polar difference is about 40 degrees Celsius today but was 20 degrees during the warm Eocene Epoch and 60 degrees during Ice Ages.” This difference has more to do with changes in the Earth’s rotation, like wobbling, than anything else. According to Mr. Lindzen, this effect is some 70 times as great as human-made greenhouse gases.

OK, back to clouds. Cumulus clouds, the puffy ones often called thunderclouds, are an important convection element, carrying heat from the Earth’s surface to the upper atmosphere. Above them are high-altitude cirrus clouds, which can reflect heat back toward the surface. A 2001 Lindzen paper, however, suggests that high-level cirrus clouds in the tropics dissipate as temperatures rise. These thinning cirrus clouds allow more heat to escape. It’s called the Iris Effect, like a temperature-controlled vent opener for an actual greenhouse so you don’t (existentially) fry your plants. Yes, Earth has a safety valve.

Mr. Lindzen says, “This more than offsets the effect of greenhouse gases.” As you can imagine, theories debunking the climate consensus are met with rebuttals and more papers. Often, Mr. Lindzen points out, critics, “to maintain the warming narrative, adjust their models, especially coverage and reflection or albedo of clouds in the tropics.” More tuning.

A 2021 paper co-authored by Mr. Lindzen shows strong support for an Iris Effect.  Maybe Earth really was built by an engineer. Proof? None other than astronomer Carl Sagan described the Faint Young Sun Paradox that, 2.5 billion years ago, the sun’s energy was 30% less, but Earth’s climate was basically the same as today. Cirrus clouds likely formed to trap heat—a closed Iris and a negative feedback loop at work.

In a 2015 Nature Geoscience paper, Thorsten Mauritsen and Bjorn Stephen at the Max Planck Institute for Meteorology reran climate models using the Iris Effect and found them better at modeling historic observations. No need for tuning. Wouldn’t it be nice if the U.N. used realistic cloud and climate models?

Earth has warmed, but I’m convinced negative feedback loops will save us. Dismissing the Iris Effect or detuning it isn’t science. Sadly, climate science has morphed into climate rhetoric. And note, Treasury Secretary Janet Yellen explained in April that green spending “is, at its core, about turning the climate crisis into an economic opportunity.” Hmmm. “Catastrophic,” “existential” and “crisis” are cloudy thinking. Negative feedback is welcome. Dissenters from the catastrophe consensus on warming are worth listening to.