Global Cooling and Volcanism

After viewing this chart the first time I always wondered what role vulcanism played in the Little Ice Age and other global cooling events.

Volcanic activity

I have noodled the idea for years that sun spots, or lack of spots, have influenced the climate of the planet and that there was some connection between solar activity and vulcanism on the earth. Not finding any highly evident connection, I just accepted the idea that volcanism was cyclical and influenced the global temperature.

That is until I say this graphic and read Willis Eschenbach Stacking Up the Volcanos post


Willis’ Conclusion:

Well, I’d say that this is very strong evidence that the global temperature is not at the mercy of changes in forcing as is generally believed. Volcanic eruptions clearly and measurably reduce the incoming sunlight due to volcanic aerosols both reflecting and absorbing solar energy.

However, this does not cause a corresponding reduction in global average temperature. Instead, the climate system responds to reductions in forcing from eruptions by increasing the amount of energy entering the system, as well as by reducing the heat loss from the surface, in order to stabilize and maintain the surface temperature within a fairly narrow range (e.g. ± 0.3°C over the 20th century).

Willis’ full post is HERE.

Following Willis’s analysis of global temperatures on this page and here I have to rethink the whole issue of solar and volcano influenced climate change.   Your thoughts? 

7 thoughts on “Global Cooling and Volcanism

  1. Derek Lott June 27, 2018 / 4:54 pm

    If the Earth is so good at maintaining it’s own stable temperature within a narrow band, why have there been so many Ice Ages in the past?
    Could they all have been caused by meteor impact??

    • Russ Steele June 28, 2018 / 7:00 am

      Accoreding to the ice core data, the ice age are a cycle. Metor impact would be more random Here is a current theory:
      Over long periods of time the temperature of the Earth alternates between a cold ice age phase and a warm interglacial phase. Very small changes in the Earth’s orbit result in only a 4 degree Celsius in the global mean temperature which can have very dramatic impacts on the Earth system. One such change is shown above. The tilt (obliquity) of the Earth with respect to is orbit around the Sun varies between 22.2 and 24.2 degrees. When the tilt is low (between 22.2 and 23.4 degrees) ice sheets grow and when the tilt is relatively high (between 23.4 and 24.2 degrees) the ice sheets melt away. The ice age reached its peak 18,000 years ago when the tilt had risen to a value of 23.4 degrees from a low of 22.2 degrees 32,000 years ago. Since then the tilt has reached a maximum of 24.2 degrees (10,000 years ago). Today, the Earth’s tilt measures 23.5 degrees, and the large ice sheets have disappeared. The three orbital parameters that are affected are the eccentricity (how circular the orbit is) which varies with periods between 400,000 and 100,000 years; obliquity (how tilted the Earth is with respect to its orbit around the Sun) which varies with a period of about 40,000 and affects the solar radiation most strongly at the poles; and precession (changes in the distance between the Earth and Sun in a given season) which varies with a period of about 23,000 years and affects the solar radiation most strongly at the equator. These changes in the orbit of the Earth produce changes in the solar radiation received by the Earth that vary over periods of about 40,000 years, strongest at the poles, and 20,000 years, strongest at the equator. These changes can be matched with the cycle of the ice ages as revealed by the geologic record; however, the largest variation of the ice ages over the past million years has a period of 100,000 years. The 100,000 year cycle is thought to be the result of the interactions of the 40,000 and 20,000 year variations in solar radiation and various geophysical processes that occur on the Earth over long periods; however, this is a subject of continuing research.

      For more info:

      • Derek Lott June 29, 2018 / 4:34 am

        Thank you for your response, Russ.
        I am aware of the long cycles proposed by Milankovitch but there are interspersed with these long cycles abrupt short term shifts that have had large impacts on society.

  2. Derek Lott June 29, 2018 / 4:35 am

    By the way, I love your articles.
    They’re a great read

  3. The Atmosphere Guy June 29, 2018 / 5:10 am

    It might be considered likely that earthly volcanic activity and climatic variability are common symptoms of external influences and the external environment, rather than being cause and effect.
    Undoubtedly, variations in the earth’s orbit, variations in geoeffective solar activity, in solar magnetic behaviour, in the heliospheric sheet, even the ‘stellar wobble’ (as used to detect exoplanets) of the sun in response to the whole solar system orbital structure will all have their effects on earth; stresses and strains in the geophysical, the climatic and the geomagnetic structure, however slight, may give results appearing huge from the human viewpoint!
    The complexity and variability of the whole interacting structure makes any realistic analysis extremely difficult however it is important that we view the problem ‘holistically’ rather than just viewing isolated parts.
    Regards …

    • Russ Steele July 2, 2018 / 7:25 pm

      Thanks for the tip, I will check out Armstrong’s site

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