It’s estimated that at least one-quarter of the world’s population, or roughly two billion people, are now under some form of stay-at-home order because of the coronavirus.
This significant slowdown in economic activity has also led to an environmental impact, particularly in the air. And it’s already being seen from space.
Scott Collis, an atmospheric scientist at Argonne National Laboratory, said satellite imagery and other atmospheric monitors are already showing a dramatic reduction in pollution.
“Over China there was a 50% reduction in things like nitrous oxide and carbon monoxide due to the shutting down of heavy industries and factories,” he said.
Some studies have also shown a drop in those same pollutants in New York, Collis said, but that was mainly due to a reduction in traffic as opposed to reduced emissions from factories.
The sharp decline in commercial air travel is also reducing pollution, but according to Collis, the drop in the number of planes flying is also, perhaps surprisingly, impacting our ability to forecast the weather.
“Commercial aircraft are actually instrumental in taking profiles of air temp, humidity, wind speed and direction. This is most important on takeoff and landing because you get a nice measurement where you can see how these change with height,” said Collis. “Before this coronavirus shutdown of air travel NOAA would receive approximately 900,000 measurements every day from these aircraft. At the moment this has dropped to about 300,000.”
Collis said the reduction in data inputs will inevitably mean forecasts are less accurate, although how much those forecasts will be degraded is “open to question.”
Changes in human behavior prompted by the pandemic create a rare opportunity for scientists to study how humans interact and influence the environment on a global scale.
“This is what we call a natural experiment, a sudden perturbation or change from the normal, that allows us study a stop and a system’s response to that,” said Collis. “This time the system is planet Earth.”
Climate and weather systems are incredibly complex, so any opportunity to study such significant changes is valuable to researchers.
“The atmospheric system, the weather system that controls what we experience – controls weather and controls climate – has many different components to it. Everything from the smallest snowflake to the largest thunderstorm – and they all interact. When you take all of these interacting components together, you end up with a very difficult to measure and simulate system. An event like this is going to tell us more and teach us more,” said Collis. “We certainly have a lot more to learn.”
One hopeful sign amid the crisis is that there are small signs of how quickly natural systems may be able to bounce back when human behavior changes. But that may be wishful thinking.
“I think time will tell. I think we need hard data to look at this. When you see reports in the media, wonderful, heartwarming reports, they are still anecdotal,” said Collis. “I trust the statistics and the science … There are a lot of people right now who are sitting in their living rooms and downloading data right now and making complex measurements to try to understand what is happening. But these things happen at various time scales. We’re still very early in terms of planetary response, in terms of how the Earth breathes and changes in this changed situation. So I think we will see the signature of this event in the data for many weeks to come.”