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.
