You may have noticed that the air is a bit cleaner since the COVID-19 shutdown. It’s true; the measures put in place to slow the spread of the virus have caused a general slowdown in economic activity and there are fewer vehicles on the roads. Some satellites in Earth orbit have observed this decrease in pollutants such as nitrogen dioxide, a gas emitted by motor vehicles, power plants and industrial facilities.
During the second week of March, when California began enacting COVID-19 measures, the Tropospheric Monitoring Instrument (TROPOMI), a European Space Agency satellite, observed reductions in nitrogen dioxide over the state. Then, during the third and fourth weeks of March, when California announced and then implemented statewide “shelter-in-place” orders, the satellite saw nitrogen dioxide drop even further. .
Similar satellite maps of nitrogen dioxide over china show a decline related to economic confrontation following the coronavirus outbreak there. But while a reduction in pollution is certainly good news, it does not mean that climate change is receding.
Concentrations of carbon dioxide, the gas primarily responsible for trapping heat in the Earth’s atmosphere, have risen from 413 ppm this time last year to 416 ppm now. Indeed, on average, one molecule of carbon dioxide will remain in the atmosphere for about four years. Then, when they leave the atmosphere, the carbon dioxide molecules swap places with carbon dioxide in the ocean, which means that the extra carbon dioxide we added to our atmosphere by burning fossil fuels for decades will remain in our environment for centuries.
The current decrease in carbon pollution is therefore only a blip in the overall picture and the climate crisis will be with us for a very long time.