Mar 14, 2015

Mass Deaths in Americas Start New CO2 Epoch

An interesting article in Scientific American proposes that the death of native Americans following European colonization of America caused massive reforestation of former farmlands, which sequestered mass amounts of carbon dioxide from the atmospher, which led to the mini ice age.

"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."

An interesting theory which adds to a number of other theories about what caused the mini ice age and other ices ages. The Wiki articles below describe the little ice age and major ice ages.

The graph below from the wiki article shows global temperatures for the past 400,000 plus years. Ice ages come and go as the graph shows. The little ice age really does not show up in this long term graph. 

Look at how the first bar - global temperature - correlates with the second graph - which is carbon dioxide. It correlates. Of course correlation does not prove causation.  And the first 390,000 plus years did not involve very many humans and no agriculture. Something else must have caused carbon dioxide levels to rise and fall.

Thanks to Taffy Cannon for sharing this article.

Richard Anderer I'd not heard this theory but find it interesting. Since the Little Ice Age was pre-Industrial Revolution I have often wondered what might have caused cooling over that period of time. With or without 'man' the earth has undergone tremendous change. However, with over 7 billion people breathing in and out (plus other functions we won't discuss) how can we not say humans are a factor in current changes?