| Summary: | In Central Asia, Pleistocene glaciations occurred in two climatic regimes: arid regions where annual precipitation was <150 mm, and more humid regions where it was greater. In the former, the precipitation controlled the ELA and size of the glaciers; in the latter it was temperature. Temperatures are less variable spatially than precipitation, and therefore the glaciers of the arid regimes have a wide range of ELAs. This leads to highly local, idiosyncratic glacial chronologies because of local rain-shadow effects as well as nuances in the pattern of moisture distribution by storms affected by topography and the jet stream. However, southern Siberia appears to have followed the global pattern of glacial advances, while the complexities are largely farther south.Mountain glaciers in arid Central Asia are important in and of themselves because their meltwater is necessary to sustain some communities through dry seasons when rainfall is slight. Furthermore, glaciers are commonly associated with ice-dammed lakes that can rupture to release dangerous outburst floods downstream. However, because of their widespread distribution in Central Asia, the most significant role for glaciers may be as a warning system for climate change and a signal for the degradation of permafrost and consequent release of greenhouse CH4 into the atmosphere.
|
|---|