Friday, May 8, 2020

COVID-19, Air Quality, and Climate Change

A lot of people have commented to me that the air has seemed quite clear in recent weeks and I too have noticed.  As reported recently by the media, this anecdotal observation has been put to the test by Dr. Logan Mitchell, a Research Assistant Professor in my department (Atmospheric Sciences).  Although you may have read articles in the Trib or Des News, he has his own summary available here and it's worth a look.  Although it's hard to tease out meteorological influences, a pretty strong case can be made based on his analysis air quality has improved, with the exception of ozone, which Logan discusses in his write up.  A quick note that this work is preliminary and has not yet been peer reviewed.

I have also been asked by several people if the coronavirus crisis might be good news for climate change.  It's a reasonable question, but my response is a pretty firm no.  First, and paraphrasing Logan's comments in his write up on air quality, any improvements in air quality or decreases in carbon emissions are overshadowed by the loss of life and economic hardship that we are currently experiencing.  Second, our society remains highly dependent on fossil fuels and, while CO2 emissions are projected to decrease compared to recent years, they remain very high and we will still see a substantial increase in atmospheric carbon dioxide concentrations this year. 

There have been some news articles stating that this year will feature the biggest "carbon crash" on record.  An example is this article early this week from the BBC, which included the figure below.  Although the forecast for 2020 CO2 emissions is a drop larger than in any previous year, CO2 emissions are so high that it will only lower us to levels near those of about a decade ago.
Thus, on a percentage basis, the drop, which is estimated to be 4-8%, is large compared to anything previous.  However, for the climate system, we're still adding lots of carbon dioxide to the atmosphere. 

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