Record summer rainfall caused severe flooding in eastern China in 2020 during the pandemic. Reduced human activity during lockdown resulted in substantially lower greenhouse gases, and black carbon aerosols during this period. A study in Nature Communications dated February 18, 2022 suggests the COVID-19 lockdown caused those severe floods indirectly. This raises several questions in our minds.
How Did COVID-19 Lockdown Cause Severe Floods?
The sudden drop in gas emissions strengthened the summer atmospheric convection over eastern China, leading to warm, moist air rising. This in turn resulted in a positive sea level pressure anomaly over northwest Pacific Ocean. These two factors combined to increase atmospheric moisture over eastern China increasing rainfall in the area.
The report describes modeling experiments investigating the root causes further. The scientists determined the reduction in black carbon aerosols had a greater impact than the decrease in greenhouse gases. They concluded reduced human activity during COVID-19 lockdown caused the severe floods in eastern China.
Does This Mean Green Energy Could Cause Floods?
Summer rainfall had gradually been decreasing over eastern and central China during the past four decades, coinciding with increased carbon aerosols in the atmosphere due to industrial activity. This phenomenon could result in large-scale storms resulting in lower rainfall. The China lockdown reversed this process during the study period.
BBC News asked study leader Yang Yang whether phasing out carbon could provoke more extreme weather events. ‘It’s a good question,’ he replied. ‘Such sudden change of the climate system would be very different from changes in response to continuous but gradual policy-driven emissions reductions.’
Once again, we learn just how delicate climate balance is on our rock orbiting the sun. The nations of the world should see past their petty political squabbles, and concentrate on the greater issues confronting humanity now.
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Preview Image: Flooded Datong Ancient Town
