America colonisation ‘cooled Earth's climate’
bbc.com
bbc.com
They were changing the use of the land, though. The hypothesis appears to be that the land that had been cultivated reverted back to forest, which meant more trees and hence more CO2 uptake. (Though even that could be questioned, since crops also take up CO2, and growing new crops every year might well take up more CO2 than a forest of trees that just grow once and then stay there.)
Did you read a different article to me? Both the UCL scientists and an unaffiliated scientist said there were also natural processes at play, but the reduction in CO2 had a large impact.
Which doesn't make sense because that small a change in CO2 cannot have a "large impact" given what we know about the sensitivity of the climate to changes in CO2.
The major bloodbaths took place further south with the overthrow and slaughter of the Inca and Aztec empires -- with populations of 12 million and 5 million, respectively.
> It's the UCL group's estimate that 60 million people were living across the Americas at the end of the 15th Century (about 10% of the world's total population), and that this was reduced to just five or six million within a hundred years.
The only thing that was that early, that rapid, and that devastating was the diseases introduced by early European visitors that preceded their colonization by decades and leagues.
What's your point?
The New Spain conquest (current Mexico) was done with the help of natives that hated Aztecs. Even with the help of gunpowder it would have been almost impossible to achieve that body count. Thus, the Spanish Crown wanted the help of the Catholic Church, so it promises keep the population to christianize them.
TL;DR: since extracting carbon from CO2 is energetically unfavorable, it needs to be powered by sunlight. Typical plants are 1-4% efficient in their overall usage of solar energy to generate sugars, and it's not possible to get above ~11% without using some totally different biochemical process.
Some plants are adapted to be more efficient than others, but I think we can be pretty confident that there are no simple tweaks to radically increase efficiency that billions of years of evolution haven't already stumbled on.
[1]: https://en.wikipedia.org/wiki/Photosynthetic_efficiency
A superior form of photosynthesis isn't easy to imagine, the one we've got seems to use nifty quantum effects to be very efficient, I think about 80%.
Earth cycles carbon, there's been a few spells when it has run out of carbon and turned it a snowball, seemingly saved by carbonate rocks being recycled by volcanoes.
I think there'll run out of phosphate before then though.
I've been hearing about this as if it's a new label for about 15 years now. I was pretty certain we've already accepted this term and generally accept it's a very clear, measurable geologic epoch.