Clear skies over South Asia, created as a result of sperm lockdowns last year, likely impacted the timing of snowmelt in the Indus basin of Pakistan and India, researchers reported Monday.
The barriers reduced emissions of soot and other pollutants as fewer people drove and electricity generation, mostly from coal, was reduced. This meant that less soot was deposited on the snow, where it absorbs sunlight, gives off heat and causes it to melt faster.
The cleaner snow in 2020 reflected more sunlight and didn’t melt as quickly, the researchers said. Overall, they calculated the delayed runoff of more than one and a half cubic miles of meltwater into the Indus, similar to the volume of some of the largest reservoirs in the United States.
More than 300 million people depend on the Indus for water, much of which begins as snow in the high peaks of the Karakoram and other mountain ranges.
The timing of the runoff of meltwater in spring and summer can be of crucial importance for the timing of the water supply. In many parts of the world, climate change has affected this timing. With warmer temperatures and a shift to more rain and less snow, more snow melts earlier. Slower runoff can therefore be beneficial and help reservoir managers store more water and maintain constant flow throughout the year.
Updated
April 26, 2021, 11:15 p.m. ET
Ned Bair, a snow hydrologist at the University of California at Santa Barbara, and the lead researcher said that while they could not clearly prove that the pandemic caused the delay, “anything else is unlikely to have caused it.” would have. “
India imposed a nationwide lockdown in late March last year that lasted until early May. Several studies have shown rapid improvements in air quality during this period, particularly in and around Delhi, which is known for having some of the most unhealthy air in the world.
Anecdotal reports also suggested that the air was cleaner over much of the subcontinent. For example, in Kathmandu, Nepal, residents reported seeing Mount Everest, 100 miles away, for the first time in decades.
When analyzing satellite remote sensing images, the researchers found that concentrations of soot and other particles on snow and ice in the Indus Basin decreased by 30 percent in 2020 from the 20-year average.
An article describing the results was published in Proceedings of the National Academy of Sciences.
Mark Flanner, an atmospheric researcher at the University of Michigan who was not involved in the study, said the results made sense. “We know the air was extremely clean this year,” he said. “The shoe fits the foot.”
Dr. Bair said the work showed how behavior change, for whatever reason, can affect water supplies. Around two billion people worldwide depend on snow and melted ice for their water. More generally, said Dr. Flanner, the study is “further evidence that cleaning up the environment can have a multitude of positive benefits that we may not be immediately aware of.”
The study complements a growing body of work on the so-called side effects of the pandemic. Among other things, researchers have documented a general reduction in greenhouse gas emissions, a shift in the timing of energy consumption in locked households, and even an increase in child eye injuries due to the widespread use of hand sanitizer.
According to Dr. Bair, the air quality values in Delhi are “terrible again”. With the recent sharp rise in Covid cases in India, Delhi and a few other cities are locked again for at least a few weeks. But if the new orders are left for the home, the effects of the pandemic on the Indus meltwater will most likely be temporary.
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