[onlooker]

http://news.uci.edu/press-releases/a-th ... -distress/
Link refers to groundwater becoming scarcer.

[sparky]

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@ subjectivist
your comment is quite correct , pre-fossil fuel , only half a dozen urban centers briefly reached the million mark or close to it , all of them experienced severe population crashes associated with violence
it always was the capital of a large empire or state and had to have excellent water borne transport ,
either maritime or fluvial ,
http://geography.about.com/library/weekly/aa011201a.htm

things changed at the start of the age of carbon , the 10th of January 1709 to be precise
within a few decades , megacities (10^ 6 population) appeared then multiplied
the first 10^7 was new york around 1930 , today there are dozen of them with the very concept of cities disappearing to be replaced by conurbation , seamless (though patchy) urban areas , extending for tens of kilometers
it's the geographical equivalent of cancer !

[onlooker]

Yes, @ subjectivist
In fact cholera and diseases associated with proper sanitation are huge problems. At present this is the case with slums or shantytowns around the world. They have poor sanitation which ends up contaminating the water supply. Not to mention lack of running water which has been a problem in the past and still is. We in rich countries take bathrooms (toilet, sink) for granted but they are conspicuously lacking in many areas around the world.

[Cid_Yama]

While Abraham Darby's invention of the Coking process was important, it took the development of John Wilkinson's boring process (precision cylinders for pistons, 1774) to allow for the building of the Boulton Watt steam pump (1776), which allowed water to be pumped from deep coal mines, before the Age of Carbon actually took off.

The previous Newcomen pump could only pump water from very shallow mines and was very inefficient, with the out of round cylinders having to be wet packed to maintain a vacuum.

The Pre-Industrial era is considered as prior to 1750 when CO2 ppm was at 260-270.

Interesting Factoid:

Pluto was at Perihelion in 1989. The previous Perihelion was in 1741. One could argue the industrial era fit within one orbit of Pluto.

[sparky]

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Thanks Cid , I would agree , having efficient machines was a critical necessary step ,
I use the Darby date as it is recorded to the day , which I think is cute .
as for the cosmology of change , I like the Pluto clock !
finally a appropriate measuring unit for civilizations timeline