In Glen Gordon's site there is a link to maps showing the impact of
glaciation on vegetation cover and the obvious support that this
cover provides for human settlements.
Has there been any analysis of the impact of this ecological factor
on the evolution of languages, Nostratic and PIE language trees in
particular?
The terrain and ecology are major factors and should be taken into
account in re-tracing the route marches of armies or pastoral
movements of people or searches for tin resources during the evolving
bronz age, up and down Central Asia.
The cultural history of the Western Himalayas with some of the
tallest mountain-ranges in the world and the impact of glacial ages
as well as younger dryas [ca. 11,000 years ago] on ancient
settlements, has yet to be written within the context of the history
of civilization of Bha_rata ca. 5000 years ago.
"The Younger Dryas (YD) was the most significant rapid climate change
event that occurred during the last deglaciation of the North
Atlantic region. Previous ice core studies have focused on the abrupt
termination of this event [ Dansgaard et al., 1989] because this
transition marks the end of the last major climate reorganization
during the deglaciation. Most recently the YD has been redated--using
precision, subannually resolved, multivariate measurements from the
GISP2 core--as an event of 1300 +/- 70 years duration that terminated
abruptly, as evidenced by an 7C rise in temperature and a twofold
increase in accumulation rate, at 11.64 kyr BP [ Alley et al., 1993]
(Figure 2)."
http://www.agu.org/revgeophys/mayews01/node6.html