Tipping points - Lecture 4 (urbanism and collapse)

what are the 5 main centres of urbanism

• Mesopotamia

• Egypt

• Indus (Harappan) Region

• Yellow River China

• Mesomerica/SW north America

what are the theories and approaches to urbanism and what are they?

• neo-evolutionism

• geographical

• hydralic theory - how we use water sources and how we explot the to allow these urban centres to develop

• Power relations – how to maintain large group sizes 

• Social evolutionary theory  

• Ideologies of states – if you have certain ideologies that allow you to develop. 

what is the definition of urbanism

interactions between people in towns and cities (about people rather than places) 

what is organic growth of cities

cities that evolved in an unplanned process

what is planned growth of cities

cities that were laid out in a predetermined way based on some geometrical design or of regularized land holdings. Planned lay out of streets could signify the presence of central control.

what is intra- muros growth

within walled area

what is extra muros

outside walls

whwat is one of the earliest cities

Early settlement Ur grows into first city Uruk. At its peak ~5800 cal yr BP 50,000- 80,000 residents. Other cities in region (e.g. Kish, Lagash), but rarely unified, generally separate city states but did identify with the region of Mesopotamia)

what is great zimbabwe

late Iron Age African town started in 11th century. By AD 1270, Great Zimbabwe was the capital of the Shona Empire that was ruled by kings who had accumulated wealth by controlling trade (gold!) between the southern African interior and the East African coast. Pop 18,000 and covering >700 ha.

when do urban centres develop in the british isles

Oppida are fortified settlement sites constructed largely in the 2nd-1st century BC (2150-2050 cal yr BP). They were involved in trade with the Roman world and in many cases the ruler had probably entered into formal treaties with the Emperor.

what is important to consider as cities grow

• Is there a relationship between the development of urban settlements and technology – such as metallurgy?

• Importance of water in the dry temperate zone and semi-desert zone – irrigation agriculture –seems very important.

• Are some cities (generally later in foundation) more related to medium-long distance trade?

• More later ‘classical cities’ survive (e.g. Athens, Rome..) – just because they are younger (developed later) or due to continuity of empire/power blocks?

• Most of these very early cities fell into decline (very few are associated with modern cities – possible exception is Mexico City) – along with their civilisations at very different times.

• Is this inevitable or part of the character of early ‘cities’ – the collapse of cultures…

what are the different theories as to why cities collapsed

• climate change

• enviromental overexplotation

• warfare

• trade problems

• contingent events

• complexity and problem solving

Classic mayan civilisation

The Central American Maya Civilization reached its peak about AD 700 before collapsing – a major transformation of its political, social and demographic organization. Cities supporting up to 100K population were abandoned

why did the mayans collapse?

climate, overexploitation, warfare. a sudden increase in temp - they couldnt find water

why did the anasazi callapse

climate, overexploitation, trade, contingent events

why did the Khmer empire [Angkor Wat] collapse

climate, warfare, trade? - enviromental damagef deforestation lead to increase isolation. possible over committed to maintaining water management systems

why did theGreenland-Iceland Norse collapse

(climate, overexploitation, trade, contingent events?)

why did the Rapa Nui [Easter Island] collapse

Loss of palm through forest clearance starting shortly after initial settlement and being virtually complete by AD 1400. Clearing land for agriculture, canoe building, fire setting and, most importantly, the use of palm trunks as rollers for the transport of the moai statues.

• The rats introduced by the settlers of Rapa Nui inhibited regeneration of the palms by eating their fruits.

• Soil erosion removed the fertile soils reducing potential for agriculture and a change in the fluvial regime leading to a reduction in available water.

• The pressures led to competition for food, further moai manufacture, periods of starvation (and possibly cannibalism), warfare (obsidian points).

• A massive decrease in population occurred before AD 1680.

who were the anasazi?

they lived in north america in desert settlesments in clifs

what is the khmer empire

The Khmer Empire, or the Angkorian Empire, is a term used by historians to refer to Cambodia from the 9th to the 15th centuries, when the nation was a Hindu-Buddhist empire in Southeast Asia.

what was the greenland colonisation

Greenland first colonised by Eric the Red in ~985 AD Population grew to 2000- 3000 in three settlements – farms abandoned after 1350 and by 1500 all gone. Written records (sagas) describe Viking sailors navigating through icefree sea zones in warm period from 800 AD - early European expansion. Reached Greenland ~985.

what was papa nui

settled by polynesians about 1000 years ago with iconic spiritual rock. population declined after 17th century

how did the agricultural spread of urbanism affect the natural enviroment

 

• Deforestation 

• Biodiversity loss 

• Exploitation of water resources  

• Infrastructure build to use that water e.g diverting water away from local rivers – possible downstream impacts. 

• Increase in soil erosion. 

• Somepoint there was a level of pollution that occurred – may have happened earlier than modern day pollution

what were the 5 potiential events for the start of the Antrhopocene?

1. megagaunal extinctions

2. ruddiman hypothesis

3. new-old world collision (orbis spike)

4. industrial revolution - 18th century

5. the great accelleration (from the 1950’s onwards)

6. the bom spike

why megafuanal

From 50,000 years ago, largest impact at Lateglacial period Initially the impact of humans seemed compelling… Strong regional components that differ – but clearly also a global scale Almost certainly multiple drivers (mainly humans and climate)

why ruddiman

Early Anthropocene hypothesis – early human impacts, notably farming from all part of the planet changed the global atmospheric greenhouse gas concentrations. This tipping point turned the Holocene into something new – beyond what was natural, from at least 7000 years BP. Regional land use changes (key drivers) led to global changes in GGCs

why new old world collision

1. 1492

2. The largest human population replacement in the past 13,000 years 2.

3. The first global trade networks linking Europe, China, Africa, and the Americas. 3.

4. The resultant mixing of previously separate biotas, known as the ‘Columbian Exchange’. 4.

5. A sharp drop in CO2 and a period of cooling temperatures.

why industrial revolution

we choose this date because, during the past two centuries, the global effects of human activities have become clearly noticeable…data retrieved from glacial ice cores show the beginning of a growth in the atmospheric concentrations of several 'greenhouse gases", in particular CO2 and CH4…..date also coincides with James Watt's invention of the steam engine in 1784.

why great acceleration

Broad period, from the 1950s onwards Focused on a clear change (increase) in trajectory of both biophysical and socio -economic processes Trends from 1750 to 2010 in indicators for the structure and functioning of the Earth System . Also globally aggregated indicators for socio -economic development.

why bomb spike

1. the radionuclide peak around 1965 from nuclear weapon testing

why were cities developed

as a result of trade, resources and defences