Short history of humans -> is now representative of before in Earth’s history?
- Homo Sapiens ~ 200,000 years ago
- Everything in book ~ past 10,000 years.
- Did we fuck up bad or are these natural disasters today natural?
Alfred Wagner: continental drift and Pangaea
- evolved into plate tectonics and crustal spreading
- periodic for billions of years
- split up ~ 180M years ago
Ocean and Atmosphere
Formation of Ocean
- 70% of Earth is water
- Water rose to surface after formation?
- Maybe from outer space
- icy comets?
- Elsa magic?
Formation of Atmosphere
- don’t know how atmosphere was formed either
- CO absorbed by ocean + plants
- ~800M years ago atmosphere -> habitable
Fire and Ice
Volcanoes
- volcanic eruption -> ash -> mass depletion (loss of diversity through failure to produce new species) -> mass extinction (mass destruction of most species)
- recent mass volcanism was ~180-160M years ago
- continental separation
- Pacific Ring of Fire: ocean-girdling zone of crustal instability, volcanism, earthquakes
- trace of Pangaea separation
- 73,500 years ago: Mount Toba eruption -> destroyed much genetic diversity in humans
Ice Age
- Ice Age -> greatest extinction
- usually accompanied by periods of heat
- Pleistocene Era deep freeze
- long glaciation
- permanent ice deep into landmasses in North
- no habitat
- 100,000 years
- Wisconsin Glaciation most recent
- smart humans survived
- tools in hunting/fishing/gathering communities + language
- short, warm interglaciation
- ~120,000 years ago -> humans
- Holocene after Wisconsin
- Global warming ~18000 years ago
- Mud floods across Mississipi Valley -> delta
- long glaciation
Little Ice Age
- 14th century
- cold
- decreased rainfall
- winds
- shortened growing seasons
- stormy seas
- advancing glaciers in Greenland and Iceland
- famines in Europe
- ended in 1850
- just minor glaciation
Impact on Humans
- humanity almost fucked
- famines in Europe
- Mongols thrived -> dynasty in China and empire
- brought Black Death to weakened Europe
China
- huge fleet under Ming empire
- 315 ships
- 27000 people
- hella trade, almost everywhere
- eventually fucked by Little Ice Age
- no rain -> famine
- ships had to stop
Tambora
- destroyed islands
- debris over entire Indonesia
- global famine