We stay close to home these days, basking under perfect blue skies surrounded by a silence we have never experienced, except perhaps Christmas morning. The skies over the silent cities, for the first time in decades, probably more like a century, are finally clearing, and the nearly permanent mantles of smog are disappearing as human activity slows to a crawl. Satellite imagery of cities around the globe showing 2019’s dense pollution levels, side by side with this year’s pale comparison, portray huge drops in urban smog as a result of the global coronavirus slowdown.    

With skies this clear, certainly we’re doing a bit of good to forestall the coming climate change crisis. Right?

You’d think.

With cars, trucks and factories idle, smog is lifting over cities, but that won't have an impact on climate change. Eri Saikawa, an Emory University professor leading discussions on greenhouse gases and atmospheric chemistry, set me straight: Yes, there were big drops in pollutants above population centers, mainly nitrogen dioxide, but unlike carbon dioxide, NO2 does not contribute to climate change. Turns out that atmospheric carbon dissipates very slowly from the atmosphere, and it will take years of these dramatic drops to have any impact at all. That’s why clean air and blue skies don’t necessarily equate to reduced threat of climate change. 

Saikawa described her travels for her work exploring air quality, talking about the lovely outdoor quality in Nepal and Tibet, but added that the widespread use of dung for fuel made for appalling indoor air quality. She spoke of sharing her concerns in China about the air quality, and how people looked at her through the soupy air with puzzlement: “This is fog!”

The current CO2 numbers captured at the Mauna Loa Observatory in Hawaii reveal that greenhouse gases are steadily increasing. This observatory noted the well-publicized 2013 milestone of crossing over the 400 parts per million level, a kind of “point of no return” for climate change that scientists agree almost guarantees dire consequences of rising seas and increased temperatures that will usher in enormous social disruptions.  

Enter David Keeling, a geophysicist who loved the outdoors. Keeling began monitoring atmospheric CO2 at the Mauna Loa observatory in 1958, when the recorded level was just 315. The measurements are tracked on what is known as the “Keeling curve.”  Since the observatory was founded on the north face of Mauna Loa, above the temperature inversion of the island and ideally located for measuring CO2, these increases have continued steadily, and the Keeling curve continues its upward trend. 

Scientists have been pondering the connection between earth’s temperature and CO2 since the 19th century, when French mathematician Joseph Fourier deduced that gases in the atmosphere help insulate the earth and retain the sun’s energy, rather than reflecting it into space. As the world adopted industrialization and began burning more fossil fuels, scientists began measuring CO2, but failed to agree on a central source of data. 

Meanwhile, let’s return to the role of the crippling economic slowdown that is certain to cause untold human pain in the coming months or years, but that is nonetheless yielding smog-free cities. Less smog means not only breathtaking views, but less respiratory and heart ailments. Smog and climate change are not intertwined, though, and each is caused by different molecules in the atmosphere. It takes decades for CO2 to dissipate in the atmosphere, and that this brief moment of reduced emissions, even if it lasts an entire year, will provide only a tiny blip on the screen on our march toward global climate change.

“There’s no silver lining to the pandemic when it comes to climate change,” said Elliott Negin, a spokesperson for the Union of Concerned Scientists, a Cambridge, MA-based nonprofit advocacy organization. “The economic collapse did reduce carbon emissions, but 20 percent of whatever is emitted this year will remain in the atmosphere for 800 years. After the pandemic subsides, countries will need to go back to transforming their energy systems to wean themselves off coal, oil and natural gas.”