Man-made climate change "began 3,500 years ago"

The Congo

From The Science is Settled Department comes news that man may have been affecting the climate for far longer than the last 40 years or so. From Scientific American, so you’ll have to wade through the alarmist phraseology:

Humans may have been causing climate change for much longer than we’ve been burning fossil fuels. In fact, the agrarian revolution may have started human-induced climate changes long before the industrial revolution began to sully the skies. How? Through the clearing of forests, which still remains the second-largest source of greenhouse gas emissions from human activity.

Sediment cores from the mouth of the Congo River—the deepest river in the world—suggest that humans may have played a significant role in changing the landscapes of Central Africa. That river curves through the world’s second-biggest lingering tropical forest, but it and its tributaries also flow through the savannas so prized by modern-day safaris.

Scientists had previously thought that a climate shift from warm and humid to seasonally cooler and drier had helped create those savannas, which covered even more of Central Africa in the past. But the 40,000-year-old record preserved in the sediment cores tells a different story. Roughly 3,500 years ago the Congo River suddenly began dumping a lot more muck without any appreciable increase in rainfall to explain such weathering. One plausible explanation is the simultaneous arrival of the so-called Bantu people, who brought farming into the region.

They cultivated oil palm, pearl millet and yams, crops that need plenty of sunlight, which, of course, necessitated clearing forests. They also cut down trees for charcoal and as fuel for the fires of iron-smelting, which enabled them to make tools and weapons. Coupled with climate change, the result was savannas—and mutually reinforcing climate change.

At the same time, the presence of crops such as millet and yams suggests that climate had already changed given that they require alternating seasons of wet and dry. So it remains unclear whether changing climate conditions created the savannas that made Bantu-style farming possible or if Bantu-style farming created the conditions for savannas and changed the climate. What is clear is that “the environmental impact of human population in the central African rainforest was already significant about 2,500 years ago,” as the researchers write in the paper presenting their findings published online in Science on February 9. (source)

Ockham’s Razor would suggest the much simpler explanation: the climate changes by itself, without the need for any man-made intervention. But that would be slightly too inconvenient to contemplate.


  1. Ray Anderson via Facebook says:

    The guilt people are on this.. If you want to create a religion, first you have to create a universal guilt. That is the aim of the Watermelon religion. Next you need your icons, polar bears for example. Then you need an enforcement division, the UN.. Freedom from religion is not an option in their minds, based on the universality of the guilt issue. Step back from their issue and realize what it is they are trying to create..lots of emotion, little in the way of facts.

  2. Ian F Somerville via Facebook says:

    They are delusional and kidding themselves.Simply clutching at straws for propaganda and impact.

  3. Slam LaBeer via Facebook says:

    If they cleared the forests it was because they wanted to grow other green plants that absorb CO2 lol such a ridiculous argument

  4. Lane Hadway via Facebook says:

    There is no man made climate change… Wake up.

  5. I wonder how the world plunged in and out of ice ages before humans walked this earth. Must’ve been all those cars them dinosaurs were driving.

  6. The Earth is quite capable of employing its own environmental damaging systems without the intervention of man. Species and habitats have come and gone long before humans set foot on the Earth … but then again, don’t let the facts get in the way of a good science theory!

  7. Miguel Rakiewicz says:

    10 February 2012 – 9:12 pm

    It all comes down to the unifying source of the
    problem: man.
    If the original homo sapiens had had the foresight to
    acknowledge the planetary destruction he was starting,
    he’d remained a nomadic animal, living off what he could
    catch or gather on any given day.
    But, no. He had to go ahead and figure out how to make fire,
    create efficient utensils and grow crops with regularity.
    In short, those first humans bit the fruit of the Tree of
    Knowledge, and we expelled ourselves from the perfection of
    the Garden of Eden.
    The rest is anecdote about how badly we’ve ruined our
    earthly abode.
    Warmeristas now claim that evil mankind has been
    ruining the whole planetary climate since the species’
    very Day One.
    Such all-seeing, all-knowing beings who know the Past and
    the Future with absolute certainty must, by definition,
    be Holy Emissaries from the Divinity Itself, as only
    His Power can change a selfish, destructive creature into
    a compassionate Saviour.
    Let us all not so blessed acknowledge their Supreme Superiority
    in all human endeavours, and follow their every suggestion,
    advice and command.

    Miguel Rakiewicz
    Toronto – Canada

  8. Ken from FL says:

    Love your website, but it’s spelled Occam’s Razor.

    REPLY: Can be both…! (Link)

  9. That was about the time beer was invented. Ah HA! Beer making = fermentation = CO2 generation. Beer making = beer drinking = beer farts = methane. We have found the source for the anthropogenic global warming. We must ban all beer, NOW!

  10. The green idiots got the time frame wrong, 40,000 or so years ago aboriginals arrived on a heavily vegetated continent and use firestick farming to clear much of it to a more habitable level…. 3,5000 years? pffft Australia had already been cleared of more of its thick vegetation by then! Perhaps the works of one of our earlier settlers helped stop the ice age??? no, not really, note that a super volcano is expected to change world temps by about 2oC then suble changes to atmospheric composition over long periods is not going to change much at all.

  11. QLD Sceptic says:

    Put another way, the only way for the earth to be saved is for the removal of the cause of the problem – ie mankind. Given that mankind has had such a significant impact from such an early stage of our civilisation, that is the only logical conclusion to draw.

    I will be more than happy to jump off the edge of the cliff…….once all the environmentalists have! Until then I will very happily continue to eat, use my car and electricity and experience not a single iota of guilt.

  12. Suzannah from Canada says:

    The period from ca. 4700-2500 is known as the Neoglacial. It was a cold period world-wide, with lots of evidence of glacier advances and increased sea ice in the Bering Sea (see Crockford and Frederick 2007, in the journal “The Holocene.” By 2500 years ago, things were warming up.

    Only their religion allows them to ‘study locally, extrapolate globally.’

    In the science field I work in, no one gets away with that kind of garbage and for good reason: it isn’t science.

  13. SOYLENT GREEN says:

    “Coupled with climate change, the result was savannas—and mutually reinforcing climate change.”

    When I saw that, I thought of this:

    Posted on June 26, 2011 by stevengoddard

    In order to determine the effects of climate change, we have to know how much the climate would have changed had it not been for climate change. Our trillion dollar supercomputer is busy modeling climate change – with and without the influence of climate change.

    Once we know how much climate change has affected climate change, we can simply subtract climate change w/o climate change from climate change with climate change. and the difference is the amount of climate change.

    We can’t say for sure that climate change is due to climate change. but we can say that we expected climate change to cause changes to the climate.


  1. […] Read the entire report. Share this:PrintEmailMoreStumbleUponTwitterFacebookDiggRedditLike this:LikeBe the first to like this post. This entry was posted in Climate Change. Bookmark the permalink. ← NY AG sues EPA for tougher soot standard […]

  2. […] Man-made climate change “began 3,500 years ago” […]

%d bloggers like this: