You’ll never guess what’s happening to Asia’s glaciers. That’s right: Thanks to climate change, they’re shrinking – and as highlighted by a new letter to Nature from Trent University, one-third of them will be lost by 2100 even if the Paris agreement is strictly adhered to and global temperature rises are kept below 1.5°C (2.7°F).
This is incredibly unlikely to happen, and it’s more likely than not that the 2°C (3.6°F) upper limit will be broken. The letter explains that, based on a groundbreaking second Nature study, there will be far less of the continent’s mountainous glaciers left if there is 3.5°C/6.3°F of warming (49 percent loss), 4°C/7.2°F of warming (51 percent loss), or 6°C/10.8°F of warming (65 percent loss) by the end of the century.
The relationship between ice loss and tempertaure changes is described as "directly proportional," in that every single degree Celsius of averted warming would save 7 percent of the ice present on each affected glacier. The same trend applies in reverse, and sadly, as is well known, the regional climate is experiencing accelerated warming at present.
When it comes to ice loss, the Greenland and Antarctic Ice Sheets – the second-most and most voluminous ice sheets in the world – often come to mind. That’s understandable: As their ice shelves collapse and unleash the landlocked ice into the sea, the oceans rise, cities fall into it, and hurricanes get worse.
The cryosphere of Asia is, for the most part, a different story. These glaciers – the third largest deposit of ice and snow in the world after the Arctic and Antarctic – feed plenty of major rivers, including the Ganges, the Indus, the Rupal, and the Brahmaputra.
Many of them are already at quite a low (warm) latitude, so they only occur at an extremely great and frigid height, at around 5.5 kilometers (18,000 feet) above sea level, one of the highest snow lines in the world. Sadly, the increase in atmospheric temperatures is reducing the permanence of this chilly boundary, and already signs of widespread melting are clear to see.
Apart from reducing the overall reflectivity of the planet, which helps to keep it cool, the loss of these glaciers will alter the water supply to their associated rivers.
As pointed out by the Guardian, plenty of locations in South Asia and China rely on these rivers for agriculture, fishing, hydropower, and irrigation. This rapid melting will not only cause sudden and potentially catastrophic floods in the summer months, but it will also ultimately lead to water shortages further down the line.
Pointing to original study, the letter concludes by noting that "achieving the 1.5 °C target will conserve a substantial fraction of Asia's water resources and that, if we fail in this regard, we will pay in direct proportion to the extent of the failure."