THE GLOBAL WARMING GAS
Viv has a degree in Applied Science Geology and is a Fellow of the Australasian Institute of Mining and Metallurgy
We are told, incessantly, that carbon dioxide is the main cause of global warming – it is not.
The primary source of surface heat is radiant energy from the sun. Minor heat comes from geothermal energy from volcanoes and hot rocks. Trivial quantities of local heat are brought to Earth’s surface by humans using stoves, cars, boilers, engines and factories powered by mined fuels such as coal, oil, gas and uranium. Even using “green” energy such as ethanol, wind or wood has a tiny temperature effect by transferring solar energy from farms and forests, to be released eventually as waste heat in cities.
Solar energy is more concentrated in equatorial areas and is moved pole-wards by the circulation of air (99.9% nitrogen, oxygen and argon), and by water and water vapour via evaporation, condensation and ocean currents. These processes are all driven by conduction, convection, latent heat and Earth’s rotation, not carbon dioxide. They are the major forces creating weather. Variations in solar cycles and cloud cover control longer term climate change.
Carbon dioxide plays almost no part in any of these dominant weather processes. Moreover, it does not burn, nor is it radioactive – it cannot produce heat.
The so called greenhouse gases (mainly water vapour and carbon dioxide) have the ability to absorb radiant energy and transmit it to their surroundings. These gases tend to retain some surface heat but also assist the Earth to shed heat from the upper troposphere by radiating energy to space. Without this ability to shed heat to space, the upper atmosphere would be considerably hotter.
However, carbon dioxide occurs in tiny trace amounts in the atmosphere, and any surface heating it could do is already being done by water vapour, which is more abundant and affects far more energy wavelengths. Also, the greenhouse effect of carbon dioxide is almost exhausted after the first hundred parts per million – adding more has very little effect on Earth’s surface temperature.
The net atmospheric effect of additional carbon dioxide is thus very minor and difficult to quantify. It probably makes the nights slightly warmer, especially in higher latitudes during winter; and it probably has little effect on daytime temperatures.
But additional carbon dioxide in the biosphere gives a major boost to all plants which feed all animals. It is not a pollutant, anywhere.