Bill Ruddiman on the Anthropocene

May 6, 2016

Everyone (except the terminally Trump) believes that humans have had the major role in changing climate in the last century.

But what about the last 8 thousand years?  Humans have had impacts ever since they started clearing forests and growing food…

7 Responses to “Bill Ruddiman on the Anthropocene”

  1. dumboldguy Says:

    IMO, the ongoing debate over the “Ruddiman Hypothesis” is one of the more interesting discussions today. My own gut feeling is that humans HAVE had a far larger impact than we once thought, and it started way back before industrial times and fossil fuel use (and when the human population was very small)

    The major concern should be that if a couple or three hundred million early agriculturalists could have such an impact, the 7.6 billion (soon to be 9+ billion) humans now burning all that fossil fuel and conducting industrial agriculture are REALLY gumming up the planetary works. The Dumanoski book is relevant here. Here’s an article that is perhaps more understandable than this interview.

  2. Lionel Smith Says:

    I have been following Bill Ruddiman’s work for some time, and to a person interested in human development and in particular maritime trade and ship building the way Bill has spelt it out in his books how ‘wrong way’ GHG trends [1] follow vicissitudes of human existence, plagues and expanding deforestation his hypotheses mooted in his paper of 2001:

    ‘The case for human causes of increased atmospheric CH4 over the last 5000 years’

    made sense.

    [1] see also Bill’s books and AGU lecture:

    1 Plows, Plagues, and Petroleum: How Humans Took Control of Climate

    2 Earth’s Climate, Past and Future

    3 Earth Transformed

    see also:

    Thanks for your link there too DoG.

  3. grindupbaker Says:

    Dan Britt has a talk on video about it “Orbits and Ice Ages: The History of Climate”. Basically he blames the Chinese (hey, a Trump similarity). Says the terracing of fields for rice paddies was a significant CH4 source. I’ve not read any of the papers mentioned. Think about Earth’s orbit properly, not the hugely exaggerated cartoon here & everywhere. Earth’s orbit is always essentially a perfect circle, but the Sun is not at its centre, currently 3.67% off, that’s the highly non-linear nature of an increasing ellipse.

  4. There was an exchange between Ruddiman and Hansen during the peer review of Hansen’s recent Icemelt, etc. paper, that updates the topic a bit, Hansen contributing an interesting quantitative point about how small of an anthropogenic nudge was needed to alter the course of global cooling 7000 years ago.


    Hansen response

  5. paulie200 Says:

    “Terminally Trump” brilliant quip, I’m stealing that! (Probably without attribution, unless someone asks, sorry 🙂

  6. Harry Twinotter Says:

    Bill Ruddiman makes a good case.

    The radiative warming from CO2 in the atmosphere is logarithmic – this means smaller increases are required to cause a certain amount of warming when you start off from a lower concentration. So even modest human contributions in historical times could indeed have an impact.

  7. addledlady Says:

    The point that leaped out at me from Dan Britt’s presentation was really just a throwaway line. That the increase of CO2 in the atmosphere at whatever-time-he-was-talking-about was an almost exact match for the loss of biomass from land clearing for farmland.

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