Friday, July 12, 2019

Finns: clouds control temperature, CO2 sensitivity 0.24 °C

Jaime has pointed out that there is an interesting physics.ao-ph paper on the arXiv:
No experimental evidence for the significant anthropogenic climate change (Jyrki Kauppinen, Pekka Malmi)
I was greatly skeptical about any meaningful content in the article. Six pages is short, affiliations are missing, and there is some kind of broken English – commas before "which" (as if they were Czech), wrong order of the words ("control mainly" in the last sentence), "green house" spelled with a space, and more. Wouldn't you expect some slaying dragon crackpots?



But many of my doubts disappeared after I read the text. If you look at the Figures 3,4, you will see quite some impressive correlation. Between what? Between the low cloud cover and the global mean temperature.

When we were 3 years old, many of us have learned that when it is cloudy, the weather is bad and it's cold. After a tropic June, Czechia has experienced a very cold week, with highs just above 20 °C. I actually preferred the luxurious reliable sunny days. Needless to say, it's both cold and cloudy.

After several dry weeks, we have lots of rain today and tomorrow.



The influence of clouds on the precipitation rate as well as temperature is obvious. These two Finns chose the low cloud cover, tried to optimally explain the global mean temperature since 1970s or so, and determined that
  • the CO2 climate sensitivity is just 0.24 °C per doubling of the gas that we call life, an order of magnitude below the IPCC estimates (which still have a huge error margin, however)
  • the reduced low cloud cover adds some 1.1 °C whenever 10% of the clouds are removed (almost equivalently, they translate it to 1.5 °C per 10% decrease of humidity measured somewhere)
So the warming since the beginning of the industrial revolution may be explained simply by the 10% or slightly smaller decrease of the low cloud cover. The contribution of the humans is below 10% of the observed temperature change, which is zero within the error margins, and may be neglected.

The next question would obviously be whether we may determine "who is driving the changes of the cloud cover". Is it possible for the fluctuations in the clouds to be this high? I don't know. I am personally willing to believe that these changes are possible, basically random, and evolving through some random walk of a sort.

Note that Finland – a cold country with the highest number of saunas per person – is one of the happy countries where climate skeptics run and have a chance to win elections – and they don't need to be afraid of their survival after every blasphemy against this postmodern religion.

I personally think that the greenhouse effect is substantial in influencing the temperature, 50% of it or so, which is not a problem, but the idea that the greenhouse effect ends up being much smaller, perhaps below 10%, seems totally plausible to me and this Finnish one is a viable scenario.

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