Using satellite data, scientists are exploring the effects that the COVID-19 pandemic may have had on the environment.

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Using a variety of remote sensing data, experts have tracked changes in the environment since the pandemic began. They have also made suggestions as to why these changes may be occurring.

The recent research, which a team of scientists presented at a virtual press conference during the American Geophysical Union (AGU)’s fall meeting, highlights the close relationship between human behavior and significant environmental issues.

The COVID-19 pandemic has had a profound effect on human behavior.

For example, because SARS-CoV-2 is a highly infectious virus that spreads primarily through respiratory transmission, physical distancing has been key to reducing its spread.

However, this has had a significant dampening effect on a range of social, cultural, and economic activities, which themselves have had knock-on effects on the environment.

Researchers have suggested that these effects have been both positive and negative.

For example, air quality has improved, greenhouse gas emissions have dropped, and water and noise pollution has decreased. Tourism has also slowed, which may aid the restoration of ecologically sensitive locations.

On the other hand, medical waste has increased, and large amounts of people are incorrectly disposing of face masks.

The scientists who presented research at the recent AGU meeting focused on what remote sensing data might reveal about the environmental effects of the pandemic.

Satellites from the National Aeronautics and Space Administration (NASA), the United States Geological Survey, and the European Space Agency gathered these data.

Although the data demonstrate evident change from images taken before the pandemic to images taken during the pandemic, more research is necessary for scientists to understand precisely what effect the pandemic is having on this change — if any.

As Timothy Newman, the National Land Imaging Program coordinator for the U.S. Geological Survey, notes, “We will need more research to clearly attribute environmental change to COVID.”

One change that Newman and team note is an acceleration in deforestation in the Brazilian Amazon rainforest between June and September 2020, as well as in the tropics near the Congo and Indonesia.

However, in the Amazon rainforest in Colombia and Peru, deforestation appears to have slowed.

Rainforests such as the Amazon are crucial for global environmental health. Around 1 in 10 known species exist in the Amazon, and the region plays an important role in stabilizing climate change.

One change that Ned Bair, a snow hydrologist with the University of California, Santa Barbara’s Earth Research Institute, notes is related to the relative whiteness of snow in the Indus River Basin.

As Bair explains, “Once the COVID-19 lockdown started in India, I immediately thought that it would have an impact on the snowpack.”

During the pandemic, industrial activity in India slowed or stopped entirely, significantly reducing air pollution. Bair and team found that dust levels on the snow, which affect its albedo — or how white the snow is — were at some of the lowest levels in the Indus for 20 years.

The uncertainty in Bair’s data means that it is not possible to conclude that the snow was brighter during the pandemic. However, he says that there is some evidence to suggest this.

Also, because the snow is cleaner and therefore more reflective, it melts at a slower rate. This could, in turn, affect water supplies for the 300 million people who depend on the Indus for water.

Nima Pahlevan, a research scientist at NASA’s Goddard Space Flight Center, looked at the effects of the pandemic on the quality of water around the world.

To do this, he used satellite data to analyze proxies in the water — such as chlorophyll-a and the water’s turbidity — as a sign of how clean it was.

The results were variable. In San Francisco, CA, for example, significant rainfall made it difficult to tell what effect the pandemic has had on water quality.

However, satellite imagery of the Hudson River in New York showed significant improvements in the clarity of its water.

According to Pahlevan, “The water has become clearer in the western Manhattan area because there were fewer people commuting to Manhattan during the lockdown.”

Before the pandemic, more people working in Manhattan would have meant the production of more sewage, which would have been treated and released into the Hudson and other local rivers.

What remains to be seen is what longer-term effects the pandemic will have on the environment.

The environmental changes the scientists found are likely the result of changes in human behavior in response to the pandemic. If those behaviors return to normal as vaccines become available, many of the environmental shifts are likely to change back, too.

For negative changes, this may not be an issue. However, being unable to maintain reductions in air pollution, for example, could have a significant detrimental effect on global health, given the clear link between air pollution, climate change, and a range of cardiovascular and respiratory health conditions.

As Profs. Robert J. R. Elliott, Ingmar Schumacher, and Cees Withagen note in an article in the journal Environmental and Resource Economics, “The pandemic offers a chance for action, but that opportunity may be fleeting.”

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