BSSb1194
Food, water and weather
JAKUB DRMOLA

Easter Island

 - relatively advanced, isolated society
 - became unsustainable
 - last tree cut down around 1650
 - collapse from 12000 to <100 people
◦food, building material, rats
◦wars, disease, slavery, …
◦
Image result for moai

Famine
 - often caused by combination of causes:
◦droughts, diseases, pests, overpopulation
◦almost always mismanagement
◦
 Irish Potato Famine (1845)
◦primarily caused by blight + overspecialization
◦1 million dead + emigration wave
 Great Leap Forward (1960)
◦primarily caused by policy + poor weather
◦30-60 million dead

Natural (mostly) famines

 - multiple famines with up to 10 million dead
◦India 1770, 1783, 1790, 1877, 1943
◦China 1860s, 1876, 1907, 1929, 1936
◦France 1693
◦Iran 1917
◦
◦Maya civilization in 11th century?
◦deforestation and drought

Intentional famines?
 Holodomor (1932)
◦caused by collectivization policies a repression
◦4-5 million dead, possibly genocide

 Yemen (2016-)
◦primarily caused by blockade and bombing
◦combined with cholera + khat farming
◦ongoing, death toll unknown

As conflict triggers
 - adverse natural conditions can trigger conflicts
 - Somalia
◦escalating cycle of droughts and mismanagement
◦failure of the state lead to collapse of fishing too
◦
 - Syria
◦population explosion and urbanization
◦droughts, poor harvest, unemployment, rising prices
◦lots of angry, young men

Floods
 - caused by abnormal weather
◦too much snow melting or too much rain
◦complicated by poor policies, infrastructure, deforestation, intensive farming, etc.
 - secondary effects:
◦crop failures, spread of disease, damaged buildings
 - Huang He floods (1887, 1931, 1938) 5 mil. dead
 - Czech floods (worst in 2002)

https://upload.wikimedia.org/wikipedia/commons/thumb/a/a8/NASA_Elbe_flood_2002_before_after.jpg/102
4px-NASA_Elbe_flood_2002_before_after.jpg



Image result for praha povoden 2002



Image result for praha povoden 2002



https://upload.wikimedia.org/wikipedia/commons/thumb/e/e5/Pisek_povoden.jpg/1280px-Pisek_povoden.jp
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Non-natural floods?

 - dams can fail
◦Vajont, Italy (1963) – erosion and landslide, 2000 dead
◦Ru, China (1975) – extreme rainfall, 2 dams, 200 000 dead
◦
 - or be destroyed intentionally
◦Operation Chastise (1943), RAF bombing German dams


Image result for vajont dam


Weather…
 - deadliest hurricanes are SE Asia
◦1839, 1881, 1970, 1975, 2008 (hundreds of thousands)
 - costliest hurricanes are in mid-Atlantic/Gulf coast
◦1992, 2005, 2008, 2012, 2017 (up to over $100 billions)

 - tornados are not so bad, comparatively
◦
 - lightning strikes – around 0.1 micromort
◦depends where you live

Loss of species
 - bees
◦“colony collapse disorder”
◦important pollinators, up to 10% of crops
 - fisheries
◦depletion by overfishing
 - corals
◦coastline protection and fish breeding
 - loss of medical research opportunities
◦any plants, fungi, animals

Climate change?
 - makes everything above worse and more frequent
 - instability and unpredictability of the environment increases
◦which is bad for us

 - some areas are more vulnerable than others
http://blogs.reading.ac.uk/climate-lab-book/files/2016/05/spiral_optimized.gif

Lessons to be learned
 - collapse or conflict often preceded by population boom, which then meets drop in productivity
◦but also cuts the other way
 - human societies fail at understanding and mitigating consequences distant in time and space from
their causes
 - dependent on speed and direction of feedback (positive/negative)
 - tragedy of commons