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Scientific American: black death and slavery cause the little ice age?

Looks like Scientific American has gone a bit “cosmic”: The Little Ice Age was apparently caused by black death, small pox, and slavery. The theory goes that there was a small spikey dip in CO2 levels in 1610, which was man-made. So hold your breath, that means a whole new era should start from then. This small dip of dubious causality, plus the correlation of oddly unclimatic things like slavery, seems to make the spike worthy of an impressive sciencey title, lo, a new era is born  — The start of the Anthropocene.

Let’s not mention that temperatures started falling from 1400 AD. That’s 200 years  before the CO2 spike down. Cause and effect are so passe in postmodern science.

Mass Deaths in Americas Start New CO2 Epoch

Scientific American:

The atmosphere recorded the mass death, slavery and war that followed 1492. The death by smallpox and warfare of an estimated 50 million native Americans—as well as the enslavement of Africans to work in the newly depopulated Americas—allowed forests to grow in former farmlands. By 1610, the growth of all those trees had sucked enough carbon dioxide out of the sky to cause a drop of at least seven parts per million in atmospheric concentrations of the most prominent greenhouse gas and start a little ice age. Based on that dramatic shift, 1610 should be considered the start date of a new, proposed geologic epoch—the Anthropocene, or recent age of humanity—according to the authors of a new study.

In any climate astrology it is important to have a hockeystick graph. I know of no global proxy that produces a temperature graph like this. But it’s easy to get this shape by comparing smoothed low res old proxies to high resolution modern adjusted thermometers. It’s just a really bad way to do science. I want the same proxy from start to end. Give me the modern temperature in tree rings or clam shells or sediments, but let’s stop pretending there are no proxies left on Earth after 1980. Has Earth ran out of mud, trees, corals or shells, or do those “modern” proxies give the wrong answer?

120 Northern Hemisphere proxies show the world was as warm as now 1000 years ago.


See how CO2 dipped in 1610. Note how temperature didn’t.


The whole theory rests on the “coincidence” of a CO2 dip of 7ppm in 1610 with the depth of the Little Ice Age, er, apparently 180 or so years later (according to their graph). Greenhouses gases can absorb infra red at the speed of light, and they drive the climate, we just don’t see the correlation, right? Yeah, baby.

The CO2 drop coincides with what climatologists call the little ice age. That cooling event may have been tied to regenerated forests and other plants growing on some 50 million hectares of land abandoned by humans after the mass death brought on by disease and warfare, Lewis and Maslin suggest. And it wasn’t just the death of millions of Americans, as many as three quarters of the entire population of two continents. The enslavement (or death) of as many as 28 million Africans for labor in the new lands also may have added to the climate impact. The population of the regions of northwestern Africa most affected by the slave trade did not begin to recover until the end of the 19th century. In other words, from 1600 to 1900 or so swathes of that region may have been regrowing forest, enough to draw down CO2, just like the regrowth of the Amazon and the great North American woods, although this hypothesis remains in some dispute.

Maybe humans caused the CO2 dip (maybe) but the climate was cooling before it, and kept on cooling after it as though nothing had changed.

Scientific American goes on to navel gaze about exactly when this mythical era called the Anthropocene began. They could change the name to Science Fashions Monthly. Should we chuck out the name “Holocene”? Vote Now!  Plus Three great: Anthropocene Moments. Don’t miss it!

The man-made global warming camp has had no answer to the skeptic’s point that global warming started a long time before our CO2 emissions rose, and their models don’t know what caused the Medieval Warm Period or the Little Ice Age. This Nature paper and Scientific American article tells us nothing about the climate, but everything about the power of monopolistic funding to frazzle logic and reason.



Simon L. Lewis & Mark A. Maslin (2015) Defining the Anthropocene  Nature, vol 519, p 171–180, doi:10.1038/nature14258

(Scientific American is part of Nature Publishing Group.)

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