As countries around the world struggled to control the disease, they imposed temporary strikes.

Scientists now use satellite and ground-collected data to understand what this gap in human activity can tell us about the atmospheric cocktail that creates urban pollution.

Most of the preliminary data was shared at the annual meeting of the American Geophysical Union in December.

It is already known that human activities have significantly been reduced in April due to a dramatic drop in greenhouse gas emissions and a reduction in man-made seismic noise. That quiet period did not last long, but carbon dioxide emissions began to rise again in the summer.

April 2020 Global CO2 emissions from fossil fuels fell by about 17 percent, but by the end of the year, annual CO2 emissions to the world were 7 percent lower than in 2019.

That reduction was so short compared to hundreds that the gas in the Earth's atmosphere would last for many years to put a ton on the planet's atmospheric CO2 level.