Tomas Pueyo Profile picture
Sep 4 18 tweets 6 min read Read on X
Climate caused the US Civil War, because:
1. Slavery was the main cause of the war
2. Different crops were the main cause of slavery
3. Climate caused different crops in the North vs South

This is terribly important to understand the US today and how to heal it
🧵
1. Slavery was the main cause of the war: the Abolitionist North & the Slavery South were competing to expand westward to increase their political influence

But the North grew & expanded faster, to a point where it could force abolition on the South, which then seceded
In 1790, the Free & Slave states had the same population, and there were many more Slave States (8 vs 5), so Slave States controlled the Senate.

By the eve of the war in 1860, the North had 50% more population and 4 more states, giving them control of both the House & Senate Image
With this power, Lincoln's Republican Party ran on an anti-slavery platform and won. Just after that, and before the inauguration, Slave States started seceding. Image
2. But why was there slavery in the South and not the North?

Crops

Northern crops (wheat, barley, oats) have 2 key features compared to Southern ones (cotton, tobacco, sugarcane, rice):
a. They take much less work
b. Most of that work was easy to automate Image
Eg, cotton took 4x more work than wheat!

Wheat took ~35 hours of work per acre (h/a):
• Preparing soil: 13h/a
• Reaping: 14h/a
• Threshing: 8h/a

Cotton took ~130 h/a!
• Field prep: 70h/a
• Harvesting: 60 h/a

How is that possible!? Image
The soil where wheat, barley, & oats grow is easier to prep because climate is drier and cooler, so crops have fewer pests and weeds, and there's no waterlogging

Grains grow to a similar height and at the same time, so they can all be reaped together.
They're easy to store. Image
These features also made them easy to mechanize:
• Machines didn't get stuck in mud
• They didn't need parts to adapt to different plant sizes
• Grains are tough and can stand a beating Image
Meanwhile, cotton grows in hotter & humid climates, which means more pests, more weeds, more waterlogging, and so more soil prep

Cotton bolls open at different times, requiring several runs to pick them Image
And cotton mechanization was too hard for 1850:
• More mud and uneven soil (for water draining) were too hard for machines
• Cotton boll fibers are delicate, requiring human hands

For similar reasons, tobacco, rice & sugarcane require much more work than wheat, barley & oats Image
Why does this matter?
Because this was the source of slavery

It existed in both the North & South in 1800, but it disappeared in the North over the following decades because it was not necessary
So, little labor for Northern crops:
➡️A single homestead could work a big farm
➡️Ppl literally reaped what they sowed, so really cared about improving yields
➡️It could mechanize, requiring investment
➡️Machines made Northerners more productive, increasing wages
In the 1800s South, labor was the biggest cost of farming, so slavery made growing cotton, tobacco & sugarcane profitable. That's why all cash crop areas (including the Caribbean & Brazil) had so much slavery Image
So the South invested in slaves vs machinery. The more it did, the more its entire economic system depended on slavery. In 1860, the value of slaves was higher than the capital of all US railroads, factories & banks combined!
In sum:

Climate made Northern crops cheap to grow & easy to automate. This made farmers richer, fostered entrepreneurship & industrialization, & made slavery superfluous.

This also made the North grow faster, as most immigrants moved there Image
In contrast, Southern crops took lots of labor and were hard to automate, so slaves were crucial to grow them profitably. This locked it into slavery.

Slavery also pushed wages down, so few immigrants moved South, condemning to be outgrown by the North, which imposed abolition
Why does this matter so much?
Because if we understand history as a mechanism, the result of massive, hidden forces like climate, crops & economics, we can stop blaming each other for terrible past deeds, and instead steer humanity in the right direction, together. Image
There's a million more things to say about this, from the role of malaria & yellow fever, to the economic importance of cotton, immigration patterns, & more. You can read them here



Next: how all this predetermined the US of today. Follow for more!unchartedterritories.tomaspueyo.com/p/climate-caus…

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More from @tomaspueyo

Aug 14
Moscow is one of the weirdest capitals:
• Biggest European city
• Extremely cold
• Little farmland
• To Russia's extreme west
• Not on a coast or main river

How did it create the biggest country on Earth?

It involves horse archers, human harvesting & tiny animals 🧵
The first shocking fact is that Russia is so far north it's at the edge of arable land. How can you create a capital with so little food? Why not in the middle of the most fertile area on Earth? Image
This far north is extremely cold
Moscow is the 3rd coldest capital in the world and by far the biggest: with 20M ppl, its metro population is 8x bigger than the 2nd biggest cold capital, Stockholm!Image
Read 20 tweets
Jul 28
This map tells you how a seemingly innocent difference, like wheat vs rice eating, can have dramatic political, economic, and cultural ramifications:
🧵 Image
The areas that harvest wheat vs rice are different. Why?
Because of climate
Rice needs heat and lots of water. Ideally, flooding the fields to also kill weeds. Rice dies with frost.

Wheat resists it well, prefers cooler temperatures, but dies when it's flooded Image
Read 12 tweets
Jul 7
Did you know the West's trade deficits to China are not recent, but started 2000 years ago? This is the story of how silk, porcelain, tea, opium, and silver have determined the history of the world 🧵
The Romans already complained about deficits to China! Mainly because of silk Image
Back then the Chinese already preferred manufacturing and selling products than consuming foreign products. Chronicler Solinus ~200 AD: The Chinese "prefer only to sell their products, but do not like to buy our goods."Image
Read 12 tweets
Jun 25
Why did 🇮🇱Israel strike 🇮🇷Iran now, and not months or years ago or in the future?

A unique combination of a dozen factors converged to make the moment unique for 🇮🇱Israel: 🧵
1. No Hamas to its southwest
2. No Hezbollah to its north
3. No Assad threat to the northeast
4... Image
4. No more Syrian army to attack 🇮🇱Israel's planes: As the new forces of HTS took over Syria, Israel bombed all the existing Syrian military. No more fighter jets or surface-to-air missiles to threaten 🇮🇱Israel Image
5. Ability to fly over Syria to refuel
This is critical, because 🇮🇷Iran is ~600-1000 miles away from 🇮🇱Israel, so 1200-2000 miles round trip

The range of Israel’s stealth F35 is only about 1,350 mi
To operate inside 🇮🇷Iran, 🇮🇱Israel needed refueling over Syria Image
Image
Read 7 tweets
Jun 23
Was 🇮🇷trying to get a nuclear bomb?

1. From Feb 2025 to Jun 2025, it increased its amount of enriched uranium by 50%
2. It now had 400kg of highly enriched uranium, enough for 9-10 bombs
3. This is 60% enriched uranium. Fuel only requires 5% enrichment.
4... 🧵
4. It's easy to go from 60% to 90% (weapons grade), it only takes weeks
5. The only country on Earth with such enriched uranium and without a bomb is 🇮🇷Iran
6. The IAEA (nuclear watchdog) found 3 secret nuclear sites
7. When 🇮🇷Iran didn't respond to this accusation, the IAEA censured it
8. 🇮🇷Iran responded to the censoring by saying it would open a 3rd enrichment site in a secret spot
Read 9 tweets
Jun 22
Now that the 🇺🇸US has bombed 3 of 🇮🇷Iran's nuclear sites, where will the war go from here?
It depends on 🇮🇱Israel: 🧵
🇮🇷Iran never wanted the war, and its forces are being decimated. Its ability to send missiles to 🇮🇱Israel is being degraded every day. If it could sign a ceasefire while saving face, it would Image
Meanwhile, 🇮🇱Israel has kept striking Iran non stop. Its daily airstrikes didn't go down substantially in the first few days. Its ability to keep striking 🇮🇷Iran remains unabated

So when will it stop? Image
Read 13 tweets

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