Is the environment really recovering due to coronavirus?

Nitrogen levels have dropped by half in Abu Dhabi, the Himalayas are visible for more than 100 miles in India's notoriously smoggy Punjab state, rare leatherback turtles are returning to beaches in southern Thailand and a tribe of wild mountain goats take a leisurely stroll through a deserted town in Wales.

These are just some of the unusual phenomena that seem to show how nature is flourishing as humans around the globe have been forced to take shelter by the restrictions to curb the Covid-19 pandemic.

On Twitter, the hashtag #NatureIsHealing is being used to highlight myriad examples of the natural world bouncing back during the coronavirus lockdowns.

Fake news Tweets aside (sadly, there were no dolphins spotted in the canals of Venice), the number of verified instances of ecosystems rapidly improving during the past few months has caught the attention of even the most experienced conservation scientists.

Hays Cummins, a professor of geography at Miami University in Ohio, is, however, unsurprised by what has been happening.

“It makes sense that when you shut things down, animals that are on the edges of communities are going to move in,” Prof Cummins said.

Places that have been particularly strict with Covid-19 lockdowns seem to be observing nature returning more than those that have implemented less-draconian measures.

On climate, too, he notes, the economic slowdown due to coronavirus has undoubtedly reduced the amount of pollution in our atmosphere and ecosystems, and the results can be seen worldwide.

Unfortunately, though, as a billion people prepare to celebrate the 50th anniversary of the biggest secular "holiday" of the year on Wednesday – Earth Day – Prof Cummins says that this environmental rebound will only be temporary.

“Over the long-haul, in terms of global climate change, we are already at levels of carbon dioxide in the atmosphere that we have not seen as a species,” he says. “Because of the residence times of carbon in the atmosphere, in the oceans, in sediment and elsewhere, that carbon is there and it’s going to stay in these reservoirs. We’re going to have to deal with that regardless of what is happening right now.”

The data tell a similar story. According to Our World in Data, a scientific research publication, over the past century there have been several drops in annual global carbon dioxide emissions. The most significant occurred in the wake of economic downturns – carbon emissions fell by about one billion tonnes during the Great Depression, and by almost 500 million tonnes during and after the 1918 Spanish flu pandemic and the First World War, which together claimed an estimated 90 million lives. In every instance, despite fleeting decreases, the general long-term upwards trend of atmospheric carbon concentration has continued.

That is not to say that nothing good will come of this brief reprieve. According to Inger Andersen, the Executive Director of the UN Environmental Programme, we all now have an opportunity for "changing our production and consumption habits towards cleaner and greener".

But that, of course, would take political will. In the world's leading economy at least, political will for responsible green growth is in short supply. Since US President Donald Trump took office in January 2017, the US has gutted dozens of environmental regulations – most recently a rollback last week of an Obama-era rule that forced the country's coal plants to cut back emissions of mercury and other human health hazards.

“While this [coronavirus] crisis is happening, the US administration is rolling back one environmental regulation after another,” laments Prof Cummins. “It’s very alarming.”

For this Earth Day at least, #NatureIsHealing may be more a virtual expression of hope than a representation of reality.