Australia: The Land Where Time Began

A biography of the Australian continent 

Climate Change Science – Human Activities and Global Warming

Farmer & Cook say there are specific human fingerprints on the current phase of global warming, and they are pointing directly to anthropogenic activity as the main source of global warming over the last half of the 20th century and continuing into the 21st century.

  1. The stratosphere is cooling - As the troposphere warms less radiated heat from the Earth’s surface is escaping to warm the stratosphere, so the stratosphere cools. This cooling has been measured by radiosondes (weather balloons) and satellites. If the Sun was causing global warming the stratosphere would be warming as well as the troposphere.

  2. Tropopause rising – as the air in the troposphere warms it expands which results in the tropopause, the top of the troposphere, being shifted higher.

  3. Less heat is escaping to space – Satellites have detected a reduction in the heat escaping to space at the particular frequency of CO2, which is direct physical evidence that the greenhouse effect has increased significantly. It is shown by this evidence that atmospheric concentration CO2 is the cause of global warming.

  4. Nights warming faster than days –If the global warming is occurring as a result of an increased greenhouse effect certain warming patterns should be observed, such as the nights warming faster than the days. This is currently being observed.

  5. Winter warming faster than summer – It is shown by records from land and sea, as well as satellite records, from the Southern and Northern Hemispheres that winters are warming more rapidly than summers.

  6. Coral contains more fossil fuel carbon – Carbon-12 (12C) comprises 99 % of atmospheric carbon dioxide, and is the most common carbon isotope in the atmosphere. Most of the remainder is comprised of carbon-13 (13C). Plants preferentially select carbon-12 over carbon-13, which is slightly heavier. This leads to the ratio of carbon-13 to carbon-12 being lower in plants than in the atmosphere. Fossil fuel is derived from plants from the distant past, therefore when fossil fuel is burned more carbon-12 is released into the atmosphere. The ratio of carbon-13 to carbon-12 in the atmosphere should be decreasing if the increased carbon dioxide is being added by the burning of fossil fuel. And this is what is presently observed, this ratio is decreasing.

  7. Stratosphere shrinking – Satellite measurements have detected that the thermosphere and the ionosphere are shrinking. It is expected that the ionosphere will cool and contract as a response to global warming, which is what has been observed by satellites.

  8. Atmospheric oxygen concentrations declining – the concentration of oxygen in the atmosphere is declining in line with the rising carbon dioxide concentration, as would be expected from the burning of fossil fuel, as it uses atmospheric oxygen to produce carbon dioxide.

  9. Rising fossil fuel carbon concentration in the atmospheric – See Coral contains more fossil fuel carbon.

  10. Increased heat returned to the Earth – The amount of heat escaping to space is declining, as it is being reflected back to the surface of the Earth. This has been confirmed by measurements at the surface, where more incoming infrared radiation is being observed. More heat is seen to be returning to the Earth at the frequency of carbon dioxide. Hence the conclusion that this experimental evidence has demonstrated the connection between the increasing greenhouse gas atmospheric concentrations and global warming.

  11. Ocean Warming Pattern - The heat content of the ocean has increased significantly over the past 40 years, with about 93 % of the total of the Earth system going into warming the ocean over the same 40 years. The cause of this warming signal has been investigated (Barnett et al., 2005) and the conclusion reached has been as follows:

    “[The increase in ocean heat content] (Farmer & Cook, 2013) cannot be explained by natural internal climate variability or solar and volcanic forcing, but is well simulated by 2 anthropogenically forced climate models. We conclude that it is of human origin, a conclusion robust to observational sampling and model differences. Changes in advection combine with surface forcing to give the overall warming pattern. The implications of this study suggest that society needs to seriously consider model predictions of future climate change”.


    At the present several billion tonnes of carbon dioxide are being emitted into the atmosphere every year by human activities. Though Farmer & Cook suggest it could be a coincidence that there are such sharply increasing levels of CO2 at the same time as the increasing temperature of the Earth. Farmer & Cook point out that correlation does not mean cause and effect, but in science, when the same conclusion is indicated by several independent lines of evidence, scientists may draw conclusions with a great deal of certainty.  

    The carbon isotope that is produced by the burning of fossil fuel is main isotope of carbon that has been found to be accumulating in the atmosphere. The carbon produced by fossils fuel contains no radiocarbon (radioactive), carbon-14 (14C). Little if any carbon-14 remains in fossil fuel that has been buried for millions of years as it has a half-life of 5,700 years.

    The ratio of radiocarbon to non-radiocarbon in the atmosphere is known, so as the ratio of carbon-14 to non-radiocarbon is decreasing, it is indicated that it is non-radioactive carbon that is being released by the burning of fossil fuels, which is the main source of this release.

    Measurement of oxygen in the atmosphere is also indicating that the CO2 is from fossil fuels. Atmospheric oxygen levels are dropping in line with the accumulation of carbon dioxide, as would be expected, considering the formation of the carbon dioxide molecule consumes 2 molecules of oxygen.

    The measurement of carbon present in corals going back several centuries is yet more independent evidence that human activity is responsible for the increasing atmospheric carbon dioxide levels. A recent sharp rise in the carbon isotope from fossil fuels has been found in coral skeletons.  

    As it is possible to measure directly the carbon isotope that is released from fossil fuels it is known that humans are responsible for the increasing levels of atmospheric carbon dioxide.

    Satellites are also measuring less heat escaping to space at the particular frequency absorbed by CO2, which is direct experimental evidence of significant increases in the greenhouse effect in the Earth’s atmosphere.

    The heat that is being blocked from escaping to space is being reflected back to the surface of the Earth. This has been confirmed by measurements at the surface, where more downward infrared radiation is being measured. Farmer & Cook say that as more heat is returning at CO2 wavelengths it leads to the conclusion that this experimental data should counter decisively the suggestion that no experimental evidence has been found for the connection between the increase of greenhouse gases in the atmosphere and global warming.

    According to Farmer & Cook many lines of evidence all point in the same direction, that increasing atmospheric levels of carbon dioxide from the burning of fossil fuels is the main cause of global warming. ‘Nothing else makes sense or fits all the facts’.

    The climate of Earth is changing; some of the changes are gradual, and cannot be detected on a day-to-day time scale, such as the global increase in temperature, the gradual melting of glaciers or the continuously rising sea level. There are also other parts of the climate that are changing more rapidly, e.g., weather patterns, storms are becoming more severe and more frequent, or hot spells and cold periods that are increasing in length. Farmer & Cook say that climate change will continue to become even more obvious in future as the weather patterns continue changing.

Sources & Further reading

  1. Farmer, G. Thomas & Cook, John, 2013, Climate Change Science: A modern Synthesis, The Physical Climate Vol.1, Springer Dordrecht


Author: M. H. Monroe
Last Updated 22/12/2014
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