One of the pleasures of teaching freshman history is that you cover a large number of topics — this drives a lot of the specialists nuts, as they’d much rather focus purely on THEIR topic of interest. But I’m not being paid to teach medieval military technology, so it’s all a wash for me, and fun.
One of the new things we may be finding out, per a new article out, is that Apparently, after one-fifth of all humanity died in the virgin-soil pandemics of the Columbian Exchange, the resulting reforestation soaked up enough CO2 to gank the climate and make it colder.
Now, I’m not entirely sold on this, for a number of reasons. First, while mechanically, CO2 as a greenhouse gas is a no-brainer, the degree to which it might overwhelm other factors….well, that’s complicated. Second, massive reforestation along the lines we know happened (all that supposedly virgin wilderness, untouched by filthy human hands that the more ignorant of the environmentalists like to look at is in fact a sign of an ecosystem that had gone quite a bit out of whack) would also lower the earth’s albedo. Point blank, lots of forest is darker than lots of fields, and thus should absorb more IR from the Sun.
On the plus side, once you’re into a few million square acres, simply providing enough carbon to create all those tree trunks, in forests that literally got so dense that according to early colonists, dead trees frequently couldn’t hit the ground… that’s a LOT of carbon.
Humbling. You simply cannot do only one thing at a time.