As a preliminary, let me emphasize that the image heading this post is just that: an image. Nothing I am about to suggest is proven, necessarily accurate, or even defensible. They are merely some speculations, suggested by the image.
First, the good news; it would appear the Corona Virus has radically reduced China’s output of pollutants. If NO2 is down, presumably CO2 is as well. China is one of the largest — perhaps the largest — economy in the world these days; this could a significant — if admittedly transitory — advance in the struggle against global warming!
Of course, the improvement from January to February could simply be the result of a change in the weather. Anyone who lived in Los Angeles a few decades ago will recall the radical change a good rain would make in air quality; whole mountain ranges that had once been invisible would spring into sharp focus.
However, that doesn’t appear to explain the change above. Wordpress is insisting on cropping the featured image so as to cut off the right side of the January image and the left side of the February version; here is the full image.
The air quality in Seoul, South Korea is only slightly improved from January to February, and the area around Hanoi (to the bottom left) appears more or less unchanged as well. Conversely, the concentrations of NO2 is radically reduced in all major urban agglomerations in China; not just some of them. The area around Canton and Hong Kong, for example, has gone from a fine, bright yellow to a pallid blue discoloration less significant than the Hanoi region. The dark red blotches and vast sea of yellow once generated by the vast concentration of humanity in North China are now less impressive than the output of Seoul alone.
No, the decline is not due to an change in the weather; it’s due to a change in human activity. Else similar changes would be apparent outside of China, or some centers within China would be less affected than others. There would appear to have been a decline — apparently a virtual cessation — in economic activity within China.
This takes us to the bad news. In the long one, it might well benefit the rest of us if we were less dependent on Chinese manufactures, etc. In the short run, the effects will almost certainly be unpleasant. If China makes seventy percent of the world’s widgets, and China suddenly stops making widgets, then there’s going to be a widget shortage. If widgets aren’t being sold, widget salesmen are out of work. Machines that rely on widgets will come to a halt. The operators of those machines will be out of work.
Et cetera. This happened before; in 1929, the US stock market collapsed, and the rippling effects put not just the United States, but the world into a depression. China’s a big player these days — if she shuts down, the first effect will be that we will all at least slow down.
China claims economic growth is continuing; supposedly it’s going to rise 3.5% this quarter, and manufacturing output will have reached sixty to eighty percent of normal by the end of February ( https://www.cnbc.com/2020/02/19/coronavirus-morgan-stanley-economic-forecasts-for-chinas-growth.html ).
Unfortunately, China has a reputation for manufacturing whatever statistics suit her. If she says output is x, that tells you exactly one thing; it would suit China if you believed output was x. It might in fact be x; then again, it might well be something else entirely.
A momentary and partial decline not what the satellite image suggests; the satellite image suggests total shutdown; not just reduced factory output, but radically reduced factory output — radically reduced home heating, radically reduced power plant output, radically reduced everything. Life — at least modern, mechanized life — has come to a virtual halt. Clear skies — and everyone apparently huddled indoors. If they are up to much, they’re suddenly being very, very green about it.
Now for the worse news. Supposedly, there have been eighty thousand cases of the disease in China, and 2900 dead (https://www.worldometers.info/coronavirus/#countries). If those figures are accurate, China is radically over-reacting — to the point of economic suicide — to a disease that has, after all, affected only slightly over one out of every twenty thousand Chinese and actually killed only one out of every five hundred thousand.
If — say — there was one traffic accident in your town of twenty thousand, and one actual fatality in your county of half a million, would everyone stop driving completely? And yet the equivalent has happened in China, and it has apparently happened in all spheres of life that generate air pollution — or at least sulfur dioxide pollution.
Of course, perhaps China is merely making sure things don’t get worse. Or perhaps she is over-reacting.
Or perhaps the virus is worse than China has let on; a lot worse.
This last is hardly proven; but on the other hand, nothing disproves it.