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Humans and the planet

By Charles Hemmings - posted Wednesday, 3 March 2021

A vital issue for humanity is the extent to which human activity has a negative effect on the ability of the planet to sustain us, going forward. We have the power but probably not the will to change or modify our activities.

Climate Change

Radiometric dating on meteorite, terrestrial and lunar samples indicates that the Earth became a separate entity at about 4,500 million years ago. The climate has been changing ever since and there is no reason to expect that it won't continue to change, with or without human intervention. Climate change is driven by energy fluctuations from the Sun, eccentricities in the Earth's orbit and rotation, plate tectonics (changing distribution of continents and oceans, volcanoes) and the greenhouse effect. These drivers cause from shorter term to longer term lags in climate change.

We are presently in an interglacial period and our understanding of the equilbria that exist on the planet is far from complete. Although caution is recommended, we should not panic about climate changes that we may not have any control over and needlessly sacrifice the quality of living on the planet. Moderation and gradual moving to renewables as technology makes practical advances seems to be the most prudent option.


Greenhouse Gases

Water vapour is the principal greenhouse gas in the atmosphere. It is claimed that it contributes 95% of the greenhouse effect and given its concentration in the atmosphere this seems reasonable. Since the Industrial Revolution the concentration of carbon dioxide has increased from about 200 ppm to 400 ppm and is considered an anthropogenic effect, which is a reasonable assumption but not proven fact. Although the concentration of carbon dioxide has doubled since the Industrial Revolution, this increase of 200ppm is equivalent to 0.02% absolute change in the concentration of carbon dioxide in the atmosphere which is a miniscule change in concentration.

It has been proven that carbon dioxide is a greenhouse gas. However, being a greenhouse gas is a necessary but insufficient condition to claim that the miniscule absolute change in carbon dioxide concentration in the atmosphere since the Industrial Revolution is the main driver of climate change even in the short term.

According to Le Chatelier's Principle the atmospheric equilibrium will move to oppose and partly annul the alteration in carbon dioxide in the atmosphere. So far as the writer is aware, no clear evidence has ever been put forward that such a miniscule increase in concentration of carbon dioxide in the atmosphere can cause a significant increase in the greenhouse effect, but we should be cautious, the planet and its subsystems are complex and are not fully understood.

During the Ordivician Period about 460 million years ago, there is evidence that the atmospheric concentration of carbon dioxide was about 4400 ppm and that the planet was not a hotter place than today. It has been proposed that carbon dioxide levels increase in response to warming and further amplifies warming. Even if this is valid, it in no way quantifies the amount of warming that a miniscule absolute increase in carbon dioxide concentration would cause.

Those who panic about carbon dioxide increase do not have a good case and more practical and comprehensive solutions are needed for sustainability than have been advanced to date. There are other greenhouse gases, like methane, but the increase in carbon dioxide is singled out due to our dependence on combustion of fossil fuels, emitting carbon dioxide. Our dependence on fossil fuels is something we must reduce or eliminate over time, especially given the almost certain increase in population and standards of living across the planet in the future.


Due to concerns over carbon dioxide and local particulate emissions, renewable energy sources such as solar and wind have become the holy grail. They appear to be at no cost, using sunlight and wind. What is ignored is the high capital cost and life cycle considerations (meaning they are costly), the unreliability due to the vagaries of the weather, and that they are dependent on surface area for upscaling, but they are good for supplementing base line power and for niche markets. A solar farm or wind farm can only produce more electricity by increasing the area of panels or turbines.


This puts a real and severe limitation onto the application of solar and wind for large scale electricity generation such as is required for high rise buildings or industrial complexes especially. Coal-fired and gas-fired power stations and nuclear facilities remain the base-line for large scale generation as they upscale on the basis of volume rather than area, as well as being cheaper and more reliable. Modern coal-fired stations do not emit as much carbon dioxide, due to new technology (more efficient), as the old ones and many lessons have been learned from the disasters with nuclear plants over the world that should help avoid but do not guarantee that similar disasters may not happen.

Other countries, such as China, plan to build numerous coal-fired power plants, perhaps as many as 300 or more in China alone, by 2030. In the light of this to think that Australia could make a significant contribution to global emission reduction by not building one or two more coal-fired power stations is absurd. The large quantities of coal Australia exports is mainly used for electricity generation, so how hypocritical is that? Combustion of coal in China and India will have the same effect re emissions as electricity generation in Australia. There are no fences in the atmosphere. Gases are miscible and we all share the same atmosphere except for short term local concentrations, as happens after massive burning off, volcanoes and concentrated local emissions from cars and industry.

Fossil fuels are a non-renewable resource and we must eventually phase them out. Use of non-renewable resources is not an option in the long term.

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About the Author

Charles Hemmings has a background in metallurgy, earth sciences and business. He is retired.

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