
Columbus blamed for Little Ice Age  - pwg
http://www.sciencenews.org/view/generic/id/335168/title/Columbus_blamed_for_Little_Ice_Age
======
zeteo
The must-read book for the context is _1491_ , by Charles C. Mann [1]. The
main point is that pre-Columbian America was much more densely populated than
previously thought, with the Native Americans managing a good deal of the
ecosystem. European contact brought in diseases (mainly smallpox) that killed
off the vast majority of the inhabitants, with momentous consequences for the
ecosystem (e.g. the extreme proliferation of bison and passenger pigeon). But
really read the book, it's very well written, based on the latest research,
and quite enlightening.

[1][http://www.amazon.com/1491-Revelations-Americas-Before-
Colum...](http://www.amazon.com/1491-Revelations-Americas-Before-
Columbus/dp/1400032059/)

------
russell
Interesting theory except, as others have pointed out, the Little Ice Age
started perhaps 2 centuries before Columbus. The North Atlantic ice pack was
growing by 1250. In 1315 the European climate changed permanently for the
worse with with heavy rainfall and a permanent drop in temperatures. The
deepest part of the Little Ice Age occurred with the Maunder Minimum where
sunspots virtually disappeared (1645-1715). Unfortunately, there were no
sunspot observations for the 13th and 14th centuries to to show whether the
start of the Little Ice Age occurred with a solar minimum.

~~~
saalweachter
You're confusing the end of the Medieval Warm Period with the start of the
Little Ice Age.

During the Medieval Warm Period from 950-1250 sea ice was temporarily reduced,
allowing the colonization of Greenland. This is not necessarily related to the
Little Ice Age from 1550-1850.

~~~
russell
It's really a matter of deciding when is the start of the Little Ice Age.
<http://en.wikipedia.org/wiki/Little_Ice_Age> Some put it at the end of the
medieval warn period, others hundreds of years later. I favor 1315, because
over the period of a few years the climate of Europe tanked for hundreds of
years. Of course a 1315 date argues for the cause being a long solar minimum
and not reforestation.

My opinion was greatly influenced by Brian Fagan: The Little Ice Age,
[http://www.amazon.com/Little-Ice-Age-
Climate-1300-1850/dp/04...](http://www.amazon.com/Little-Ice-Age-
Climate-1300-1850/dp/0465022723).

~~~
Steko
It's really just a matter of basic honesty to admit the consensus dating
(1550-) up front. The 11 critical comments you're following from the linked
article all fail to do this.

------
mooism2
> This new growth could have soaked up between 2 billion and 17 billion tons
> of carbon dioxide from the air.

That seems like a lot of uncertainty.

~~~
drats
I am not sure you are allowed to question climate science like that. But it
does make me wonder about large tree planting projects as an approach to
climate change. Although I've heard there are problems with water tables in
China where they have conducted green belt strategies to limit growing
deserts.

edit: [1]<http://en.wikipedia.org/wiki/Green_Wall_of_China#Problems>

edit2: -2 wow, anyone care to explain? Sarcasm not permitted?

~~~
onemoreact
Generally, sarcasm is to be avoided. It tends to downgrade the discussion and
many people will down vote comments they agree with if they dislike the tone.
It's often argued that this was even the original intent of voting and doing
anything else is the path to Reddit.

~~~
nitrogen
In response to Hisoka: it looks like your "Did Google pay you to say this?"
comment got your account auto-killed.

------
Vivtek
Wow, so in the 1400's we were _already_ on the way to anthropogenic global
warming, essentially!

~~~
hvs
Um, no? Did you read the article? It is talking about a massive
_reforestation_ event due to the Native Americans dying off. This is the exact
_opposite_ of anthropogenic global warming.

~~~
gyardley
He read the article. He's implying that we _were_ on the way to anthropogenic
global warming, and then Columbus and those who followed him inadvertently put
a stop to it.

------
jimworm
The size of California is 423970 square kilometres. At the higher end of the
population estimate (80 million), and assuming complete annihilation of the
population, that's 0.53 hectares (or 1.3 acres) of constant deforestation for
every man, woman and child.

~~~
onemoreact
This is over North and South America and I have seen estimates that disease
wiped out over 80% of the native population. Some areas lost well over 95% of
the population others much less so. But, disease tends to spread more rapidly
though more densely populated areas, so it’s effect is going to be
concentrated on farming communities. And those areas where early europeans
spent most of their time aka South America.

Still, it's hard to estimate what percentage of those people where farmers,
but based on current results from slash and burn agriculture in South America
sustained clearing of 10+ acres per person would not be unreasonable
considering the crops and methods used during that period. Also, even non
farmers are going to start a fair amount of forest fires simply by cooking
food. So over all their numbers seem far more credible than you might expect.

~~~
lizzard
What's being described is not slash and burn agriculture in the way it's
practiced now, or "deforestation", but a regular seasonal burn-off of prairie
or savanna. It prevented trees from taking hold in very wide areas. The book
1491 has good pointers in its bibliography to reputable sources about pre-
Columbian grassland burns.

------
scarmig
For an older, non popsci article treating the topic, check out this one from
2006, "Evidence for the Postconquest Demographic Collapse of the Americas in
Historical CO2 Levels":

<http://journals.ametsoc.org/doi/full/10.1175/EI157.1>

------
iwwr
Biological weapons appear to trump any other sort of manmade or natural
disaster, short of a killer asteroid.

~~~
VladRussian
it is more like the whole humanity is continuously trying to win a Darwin
Award. One can imagine galactic version of <http://www.darwinawards.com/>
where aliens laughing at human race frantically trying to once more increase
[under the "domestic /independence" sauce] production of fossil fuels instead
of just harvesting free solar and wind energy. Stupid as stupid does.

------
CountHackulus
Interesting, so to extrapolate from this theory, we could halt and even
reverse global warming by killing off tons of people. Seems obvious in
hindsight.

~~~
lambdasquirrel
I read somewhere that the US may actually accidentally come close to its Kyoto
targets because of the recession. So yes. Nuclear as your argument may be, you
are probably correct. =P

------
FrojoS
So how much forestation would be required to reverse a significant part of the
effect of the industrial revolution? Lets say the CO2 emitted in the last 30
years.

Would there be enough vacant area on earth to handle such an amount of
forestation? In Europe, I could only imagine a significant reforestation if
our agriculture becomes much more efficient.

------
jimmar
Please correct me if I'm wrong, but over its life and decomposition, isn't a
tree carbon neutral? While growing, trees basically absorb carbon, and when
they decay that carbon is released back into the air. Therefore, planting more
trees will not reduce carbon in the long term.

~~~
DavidAdams
You're correct, but only if the tree's entire carbon store is released to the
atmosphere, such as by being burned. Not all of the tree is able to decay and
release its carbon. The portion of the organic matter that fell to the forest
floor, was covered by other organic matter, stayed there for a long time and
eventually becomes coal or oil. In other words, you can end up storing a lot
of carbon in the soil.

I suppose one good way to sequester carbon is to plant trees then cut them
down at maturity and build durable buildings out of them.

~~~
bh42222
_I suppose one good way to sequester carbon is to plant trees then cut them
down at maturity and build durable buildings out of them_

Or dump the trunks into any oxygen starved bog.

Or ship them to the northern parts of the world and bury them in the shallow
permafrost layer.

Except both of those hold the risk of a sudden return of massive amounts of
CO2 to the air due to some unforeseen (fire!) event.

The most low risk is probably to turn them into charcoal, mix that charcoal
into the soil they came from and plant new trees there. As long as some of the
carbon is still in the soil by the time you repeat the process, you have a net
gain of CO2 sequestration.

------
tententwenty
Speaking as a layman..this all sounds a bit far-fetched. A drop of 80 million
people in the Americas then is as nothing compared to what's happened with
world populations in the 19th and 20th centuries. Despite a growth by billions
we're still debating if climate change is definitely happening today. Maybe
I'm just becoming more cynical as I get older

