Frozen Rivers

The Asian Highlands’ glaciers, permafrost, seasonal and perennial snow, and ice-cover are a critical part of Earth’s cryosphere. From deep time, Highland ecosystems have experienced much climate and cryosphere change. These have included multiple glacial and inter-glacial periods, and in the last two millennia, the warming Medieval Climate Anomaly and the cooling Little Ice Age, about which we can compare scientific data and historical records. This chapter traces this long history of climate in the Highlands and uses it as a baseline to compare the more recent, decadal, uneven anthropogenic changes to the climate. Anthropogenic climate change, construction work, and increased aerosol contamination have all accelerated cryosphere transformation and destabilized its balance. Increased meltwater has entered the system, creating larger lakes and glacial lake outburst floods. After tracing this long history in the chapter’s main text, its boxed sidebar describes the various types of floods across the region. The sidebar emphasizes how geological and geomorphological records suggest much larger and more frequent floods occurred in the past, and these records should be considered when planning future infrastructure on flood paths.