Lecture notes for 20 February 2002.
Climate and the course of human history
Climate has influenced human history in two ways: (a) variability
has displaced or decimated civilizations and (b) climate has helped
determine the rate of development of civilizations.
Climate Variability
Source: Hubert Lamb, Climate, History, and the Modern World
Examples:
-
Indus Valley (NW India) - rise of major civilization during wet period
3000-1700 BC, then abrupt decline with drought
-
Roman Empire: northward expansion 150BC-400AD when vines could grow
in southern Britain
-
Great Silk Road across Asia disrupted by drought 300, 800 AD
-
Drier conditions in Central America 400-900AD allowed Mayan civilization
to prosper by converting forest to farmland
-
Viking expansion 800-1400 AD - conquered Britain, northern France, colonized
Iceland and Greenland;
-
Medieval Warm Period: European agriculture expanded into marginal
(high-elevation or high-latitude) areas
Climate and the development of civilizations
Source: Jared Diamond, Guns, Germs, and Steel
Rates of development of civilizations largely determined by when specialized
food production (agriculture) replaced hunt-and-gather.
| region |
agriculture began |
| Fertile Crescent (modern Iraq) |
8500 BC |
| China |
7500 BC |
| Central America |
3500 BC |
| Andes |
3500 BC |
| Eastern North America |
2500 BC |
| Sahel? |
5000 BC (possibly imported from Fertile Crescent) |
Earlier development of agriculture was made possible in Eurasia by the
large abundance of domesticable plants and animals combined with the east-west
climate zones that made gradual diffusion of agriculture possible.
In Africa, the Americas, and southeast Asia to Australia, the north-south
orientations prevented the diffusion of agriculture.
In the Northwest, abundant salmon and other fish and game produced an
unusual combination: hunter-gatherers who were sedentary and had a
highly-developed civilization.