Climate variations over the last 20,000 years

Readers, I have no idea who wrote this or how valid it is, but it is an interesting site, please check it out to see the great photos:


Home page: www.treks.org. This page: www.treks.org/arcticthe.htm. (or treks.org, select North Pole on world map).
Photos also on Google Maps, see Panoramio , select tag Arctic
Personal visits: Arctic safari ; Axel Heiberg and Ellesmere Island ; Diary visits ; Yukon (NW Canada / Alaska) . 
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Last update 28 September, 2008.


Climate variations over the last 20,000 years

Since the last ice age 16000 years ago, cold periods were uncommon from 12000 to 3500 BC, but very common since 3500 BC. This follows the general trend that should be down for the next 90,000 years, see figure above. The summary below is mostly after H.H. Lamb. “Climate history and the modern world.” His books shows that the climate has been highly variable and strongly influenced the rise and fall of cultures. Very detailled figures are in [1].

Cold period	Warm period	Event	Population
80000 BC		“Out of Africa”	35000
75000 BC		Toba megavolcanoe on Sumatra erupts. Temperature drops 5 degrees for 1000 years	10000
45000 BC		Into Australia
35000 BC		Into Europe
29000 to 24000 BP		Neanderthalers extinct
20,000 – 16,000 BC		Ice age, sea level 120 m lower; 25% reduction in biomass. 20,000 BC. First natives in Alaska and the Yukon.
	12,000 – 3500 BC	Warm periods mostly. Switch from hunter-gatherers to farming cultures. Population stress resolved and rapid expansion.
	10,000 – 9,000 BC	Many big Arctic mammals became extinct in Europe, Asia and North America by a sudden, very warm period; human hunting was likely a strong contributing factor.
10,700–10,500 BC		Start of Younger Dryas. Cold period. Speculation is that a comet hit the earth and affected big mammels biotope. (After James Kennett, 2007).	In 10,000 BC 4-5 million
	8000 – 5000 BC	Very warm period
8200 - 7200 BC		Cold period. Giant glacial Lake Agassiz in Canada emptied and influenced the Gulf Stream.
6380 BC		Brief cold period. Giant Lake Agassiz (picture) in Canada broke through an ice dam and flowed into the Atlantic Ocean via the Hudson Bay. It influenced the North Atlantic Oscillator.
4500 – 2500 BC		Cold period
3500 - 3000 BC		Move from the Sahara to the Nile delta.	In 3000 BC, 14 million
	2700 to 1450 BC	Minoan civilization on Crete. Relatively isolated civilizations in Mesopotamia, Egypt and India. 2500 BC. First natives in NE Canada and Greenland.
	1700 to 1500 BC	Dwarf mammoths of Wrangell Island became extinct
1200 - 800 BC		Mycenaean civilization, Jewish monotheistic faith. 1200-1150 AD. Migration of the “sea-people”, the Philistines, from Greece to Palestine.	In 750 BC 60 millon
600 - 200 BC		Confucius, Buddha, etc. (various monotheistic religions). Scandinavian Goth invading central Europe, first large-scale migrations of peoples in Europe (Volkerwanderungen). Monotheistic religions illegal in Greece. Fist large empires: Persia, Greece, India, China. Population stress.	Iin 400 BC 160 million.
	200 BC – 400 AD	Dominance of the Roman Republic/Empire. Polytheistic religions dominate. Christianity an illegal religion in Rome. 70 AD. Destruction of Jerusalem and diaspora. First city with over 1 mln citizen in 200-300 AD: Rome	In 200 BC, 150 million In 400 AD 190 million.
400 -850 AD		4 September 476. Fall of the Western Roman Empire. Second large-scale migrations of peoples in Europe. Monotheistic religions like Christianity, Buddhism and Islam now state religions.	In 800 AD 220 million
	850 - 1300 AD	Viking conquest of Europe. Vikings settlements on Iceland Greenland and Newfoundland. Genghis Khan (1162 -1227 AD) forms the largest contiguous empire ever. Traveling from Europe to China possible (e.g. by Catholic monks and traders like Marco Polo). Rapid expansion of various monotheistic state religions like Chistianity in Europe, Islam in the Middle East and Africa, and Buddhism in Asia.	In 1000 AD, 250 million
1300 - 1350 AD		Western Viking settlements on Greenland wiped out in 1350 AD. Eastern Viking settlements on Greenland wiped out in 1410 AD.
1347 AD		Plague killed 25 to 33% of the population in Europe.
1380 - 1580 AD	1380 - 1580 AD	Renaissance. Cold and warm periods, climate stress. First separation of church and state. Around 1300 AD. Monogamy enforced by the Catholic Church; catholic priests not allowed to marry to retain the possessions of the church. Total population and agricultural land in Britain nearly unchanged since 1500 BC.	In 1500 AD, 450 million
1580 – 1920 AD		Regular famines in Europe; Third large-scale migrations of peoples; Europe colonizing the world; 1-2.5 oCelsius colder.
1600 – 1700 AD		Very cold winters. Maunder minimum by low activity in solar spots. 2.5o Celsius cooler. Thule Innuits abandon the Canadian High Arctic.
1800 AD		3% of the population lives in cities	500 million
1815-1816		“Year Without a Summer” by the Mount Tambora eruption (Indonesia). Famine in Europe and North America by a 5o Celsius lower summer temperature. In the tropics, 1oCelsius lower.
1900		13% of the population lives in cities, average age 50.	1.6 billion
1918 flu pandemic		2.5–5% of the human population killed; 20% population affected
	1920 – 2006 AD	High activity of solar spots; 40% increase in CO2 compared to 3 mln year average. 40% (?) reduction in biomass. Secular states dominate.
	1957		2.9 billion
	2006 AD	Stern Review* suggests 1% investment of GDP in climate change reduces the economic damage by 5-20 %. 40% loss in biodiversity since 1970[1].	6 billion
	2007	50% of the population lives in cities, average age 80.
10,000 AD		Ice Age, “Back to Africa” [unlikely, since too much CO2]	1 billion or zero

*The Stern Review mentioned above can now be found here:

http://webarchive.nationalarchives.gov.uk/20100104191227/http://www.hm-treasury.gov.uk/stern_review_report.htm

Link:  http://p6.hostingprod.com/@treks.org/arcticthe.htm