Current Affair 1:

Saline lakes make up 44 per cent of all lakes worldwide and are found on every continent including Antarctica. These lakes’ existence depends on a delicate balance between a river basin’s water input (precipitation and inflows) and output (evaporation and seepage).

The reason a lake turns saline is often because it doesn’t have a consistent stream outlet, leading to a build-up of dissolved salts from water inflows. The water levels of saline lakes are naturally unstable and these lakes are generally susceptible to any disturbance.

What causes change in saline lakes balance?

This heightened sensitivity makes saline lakes more responsive than freshwater lakes to natural and human-caused factors. The main cause of change in a saline lake is disturbances in its water balance. These can be the result of natural or human-induced factors that are local, such as droughts, pollution, and upstream water diversions, or global, such as climate change, decreasing precipitation and increasing temperature.

The rapid response of saline lakes to the changing conditions makes these lakes suitable candidates for reliably reflecting the regional, and potentially global, status of water resources, and revealing crucial changes in the water balance. Unsurprisingly, many of the world’s saline lakes are shrinking rapidly, a major warning about the sustainability of regional water resources.

How are saline lakes changing?

There have always been fluctuations in saline lakes. Unfortunately, more lasting changes have become more common in recent years due to regional human activities and global climate change.

Most lakes have been shrinking and their water quality has declined. In permafrost regions of the Arctic and the Tibetan Plateau, however, some salt lakes have expanded due to areas of ice melting in a warming climate.

Iran’s Lake Urmia is a good example. Until a few decades ago, Lake Urmia was one of the world’s largest saline lakes, but it shrunk rapidly due to unsustainable human activities. The resulting problems include a decline in tourism, dust and salt storms, falling agricultural productivity and a loss of biodiversity.

The Aral Sea, once the world’s fourth-largest inland water body, is another tragic example. Since the 1960s it has shrunk to a fraction of its former size largely due to poorly planned irrigation development in the region.

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