Ian Wilson in Australia opines on climate issues beginning on PDF page 22 that the articles by Dave Shatwell about the causes of climate change in issues 129 and 130 of AIG News in late 2017 started Wilson thinking about this question. The topic received further thought in early 2018 when he prepared a lecture on the environmental legislation dealing with climate change in Queensland. Since July he has had plenty of spare time to delve more deeply into the physics and mathematical models that underlie the various claims from both sides of the debate.
There are plenty of publications supporting the link between CO2 and climate change so Dr.Wilson decided to write a concise defense of the negative position from a geological perspective. Many times he has been asked – ‘Do you believe in climate change?’ This question demonstrates a complete lack of understanding of science. Science is not a belief in dogma. Scientists are taught to develop theories from observations and experiments and to test their theories and those presented by other scientists by checking observations or testing predictions from the theories. Observations do show that temperature and carbon dioxide levels are rising but that does not prove a causal relation (in either direction). He and his son recently discovered how frequently the causality fallacy occurs in peer reviewed papers on the epidemiology of Pb, for example (Wilson and Wilson, 2016). The question that should be asked is – ‘Can you provide evidence that shows CO2 is not driving climate change?’ – as that evidence could falsify the theory. ..[but can one prove a negative?]. Wilson hopes that the following arguments show that he is a rational scientist rather than a “climate change denier”.
Evidence from Geology
It is not surprising that many of the scientists questioning the effects of human actions on climate were trained as geologists. Geological theories are devised to explain the environment in which rocks formed. They involve:
• unimaginable time frames;
• massive continents moving around the world, colliding, building mountain ranges, metamorphosing rocks and triggering volcanic activity;
• the imperceptibly slow development of landscapes by weathering and erosion;
• a wide variety of sedimentary processes; and
• an evolving fossil record.
Geology is based on observing rocks and fossils, taking geophysical measurements, conducting chemical analyses and determining isotopic ratios. What evidence is there in the 4.5 billion years history of the Earth that may relevant to climate change? The first observation is that the Earth is constantly changing. The oldest rocks on Earth show no evidence of oxidation, implying that oxygen was not a significant component of the early atmosphere. The early atmosphere on Earth probably resembled the present atmospheres of Mars and Venus which contain more than 95% CO2 (Visconti, 2016). They retain high levels of CO2 because plant life evidently never developed on those planets. That is in contrast to Earth where photosynthesis commenced in the oceans about 3 billion years ago. That process converted CO2 into oxygen. Oxygen in the ocean would have oxidized the ferrous iron in solution and precipitated banded iron deposits which are now mined as iron ore. Any oxygen in the early atmosphere probably reacted with methane to form more CO2 or increased the rate of the weathering of some rocks.
The oxygen content of the atmosphere and oceans increased slowly, and by 600 million years ago was at levels that allowed animals to evolve in the oceans. Free oxygen now forms almost 21% by volume of the atmosphere and about 5 ppm by weight of the oceans. An important conclusion from this is that despite the early atmosphere containing several thousand times more CO2 than the present, the continuous record of life and aqueous sedimentation on Earth indicates that the oceans and rivers did not boil dry (Kiehl and Dickinson, 1987). In fact, there is evidence of global glaciation about 2.4 billion years ago (Young, 2017), showing that extreme CO2 levels did not force a hotter climate. Since then, CO2 levels have generally decreased because of photosynthesis and the formation of carbonate rocks, despite minor additions from volcanoes, decaying vegetation and animal respiration (Wallace and Hobbs, 2006). Major reductions in CO2 levels occurred between 350 and 250 million years ago, in the Carboniferous and Permian Periods, when land plants flourished and major coal deposits were formed. All the carbon in fossil fuels and most of the carbon in carbonate rocks came from CO2 in the atmosphere.
Another important fact from the geological record is convincing evidence that climatic changes have occurred regularly in the past. Many of these have been cyclic, such as the recurrence of glacial events at about 300 million year intervals. Some researchers have related these cycles to continental drift and megacontinent formation (Young, 2017). Others attribute them to changes in the solar energy output. Shorter cycles during the latest million years have been studied in detail using isotopic and chemical measurements of air bubbles trapped in ice retrieved from deep drill holes into the Antarctic ice sheet (ICPP, 2013). The data show a series of glacial events (ice ages) about 100 000 years apart, separated by short inter-glacial warm periods with temperatures similar to the present. Each warm period followed a rapid 8 to 10 K rise in temperature from the preceding glacial event. The most recent rise occurred about 10 000 years ago. However, since then, average temperatures have fluctuated over a range of about 2 K, with notably colder periods such as the Dark Ages (1600 to 1200 years ago) and the Little Ice Age (700 to 150 years ago). At least some of the recent temperature rise is likely to be related to natural processes that are driving these fluctuations.
There is a Greenhouse Effect
Basic physics shows that the surface temperature of the Earth is about 33 K warmer than it would be if there was no atmosphere (Visconti, 2016). This implies that a “greenhouse” effect exists. Some gases absorb infrared energy radiating outward from the Earth. Only energy that is retained contributes to heating of the atmosphere. The rest is re-radiated into space from various levels in the atmosphere. If re-radiation is predominantly from warm air near the surface, almost all of the absorbed energy is lost and there is little if any heating. If radiation occurs from higher levels, less energy is generally lost to space because air temperature generally decreases with height (up to the Tropopause at about 10 to 15 km). This phenomenon is a result of adiabatic cooling of rising air masses and is characterized by a lapse rate of between 6 and 10 K per km rise (Zhang and Moore, 2015; Wallace and Hobbs, 2006).
Read on ... an interesting article. Concludes that higher CO2 may trigger another glacial event instead.
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