Fifty years ago, on April 22, 1970, millions took to the streets on the first Earth Day to demand clean air and environmental protection. Half a century later, the coronavirus pandemic is causing major improvements.
"If there is a silver lining from this crisis we are in, it's the fact that we are all still connected. It also reminds us that the small things we do have an impact on Earth, and vice versa," said Old Dominion University Professor of Ocean, Earth and Atmospheric Sciences Rodger Harvey.
The air from Boston to Washington is its cleanest since 2005, when NASA satellites started measuring nitrogen dioxide levels, says NASA atmospheric scientist Barry Lefer. Largely caused by the burning of fossil fuels, this pollution is short-lived, so the air gets cleaner quickly.
Compared to the previous five years, March air pollution is down 46% in Paris; 35% in Bengaluru, India; 38%in Sydney, 29% in Los Angeles, 26% in Rio de Janeiro and 9% in Durban, South Africa, NASA measurements show.
"This really reminds us all of the human impact," said Harvey.
Roads are free of cars, another part of the pureness pushing through.
"Emissions are down. This change may help us think of alternative modes of transportation soon," said Harvey.
Coyotes, pumas and goats are wandering around cities, while air across the world is becoming less polluted.
People are also noticing animals in places and at times they don't usually. Coyotes have meandered along downtown Chicago’s Michigan Avenue and near San Francisco’s Golden Gate Bridge. A puma roamed the streets of Santiago, Chile. Goats took over a town in Wales. In India, already daring wildlife has become bolder with hungry monkeys entering homes and opening refrigerators to look for food.
"As soon as we back away a little bit from mother nature, suddenly the animals respond and expand their territory a bit," said Harvey.
Aerosol pollution, which doesn’t stay airborne long, is also dropping. But aerosols cool the planet, so NASA climate scientist Gavin Schmidt is investigating whether their falling levels may be warming local temperatures for now.
Scientists think of this as a grand - but unintended - experiment that shows how much of a footprint humanity has on the planet.
"Everyone can make a difference," Harvey said. "The Earth Day mantra has always been to adopt things, from recycling to not making a giant dent in consumption."