History of Climate Change

There is an interesting new book on Climate Science written by an Italian scientist Antonello Provenzale which I found both honest and informative.  In the first half of the book he reviews the unique features of the Earth which, after some near misses, eventually  allowed life to develop and flourish. The collision of the Earth and another planet (Theia) roughly the size of  Mars resulted in a molten fused mass of both being ejected. This eventually became the moon. The moon’s  stabilising effect on the Earth’s orbit and resultant volcanism eventually led 100s of millions of years later to life developing. These first organisms were single cell bacteria/Archea  life  forms in  shallow seas, among these were unique  cyanbacteria able to photosynthesise CO2 from the atmosphere, water and sunlight  to produce oxygen as a waste product. Initially the oxygen was rapidly eliminated combining with dissolved iron resulting in today’s rich iron deposits.

It was not till much later that oxygen began to accumulate in the atmosphere. Around 2.4 billion years ago sediments indicate that sulphur appeared in the oceans which then combined with iron to produce  pyrite and increasing phosphorus nutrients . This allowed Cyanbacteria to dominate  the oceans and eventually releasing oxygen into the atmosphere,  creating the “protective” ozone layer. However the increase in atmospheric oxygen also likely led to the  snowball earth ! The intense Archean greenhouse effect was likely mainly based on methane which increasing oxygen successfully removed ! The consequent deep freeze was eventually broken by the accumulation of CO2 from volcanoes.

The CO2 greenhouse effect, high  oxygen levels and the protective ozone layer led to the Cambrian explosion and eventually to us humans ! Now we too are changing the climate a little !

I think Provenzale does a good job describing current “warming”  and what climate models are really saying. In reality all climate models are “wrong”  in the sense that they fail to simulate the actual surface temperatures T on earth. However what they can simulate is the change in temperature DT.  The earth’s climate is immensely complicated so each model chooses approximations to various processes (clouds, aerosols, carbon cycle, albedo etc). They then adjust  levels of CO2.

For this reason both data and models can  only work with temperature “anomalies” normalised to an instrumental 30 year average temperature (climate). Consequently all models by definition must agree with the data during  the normalisation period – typically ending in 1990. In fact he states “Climate models are undoubtably imperfect tools but they are currently the only ones we have to represent our planet”.

His conclusions on climate change and action to remediate it are mostly mainstream, but I very much like the honesty and style of his book. It is a well balanced argument.


About Clive Best

PhD High Energy Physics Worked at CERN, Rutherford Lab, JET, JRC, OSVision
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10 Responses to History of Climate Change

  1. Anteros says:

    Little typo – I think the 2.4 million in your second paragraph should be billion.
    It sounds an interesting book.

  2. RichardLH says:

    An accurate LP filter will do the same as climate normals, without the distortion and offsets that they bring. Climate normals are not used by any other science for that probably reason alone. They use accurate LP filters to get their results.

  3. Nick Stokes says:

    ” Consequently all models by definition must agree with the data during the normalisation period ”

    No, they are normalised to their own history only. For measured data, it is to the histoty of each station.

    • Clive Best says:

      That’s true but both stations and models averages are set to zero during the normalisation period. Models though actually calculate absolute temperatures and these mostly disagree with the measured values. Models only predict changes in temperature not absolute temperatures.

      • A similar situation occurs with tidal analysis. No one has ever been able to predict absolute tidal amplitudes of sea-level heights from first-principles models. Yet, once calibrated to a local station and it’s historical data, the models do fine. So the problem with global temperature is that there’s no possibility of a calibration given that it doesn’t cycle or produce any other marks lining up with a known forcing.

      • Ann Mousse says:

        thanks I completely got it now. If you allow each station to be there own control, like any biological +++ study does, then you don’t have any of the gridding, regional, temporal, elevation etc nonsense induced error {(1.3 C+) MAE {Normalisation zero error :-)} Hawaii study}, and conformational bias [a mosquito is still a mosquito whether it knows it or not] You can still get CO2 ES but the poor models don’t know where they are at on the zero hunt/ Thanks So Much!

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