We've had daily readings at the Mauna Loa CO2 observatory of over 418 ppm

[NNadir]

Rather startling, this:

Recent Daily Average Mauna Loa CO2

May 03: 418.12 ppm
May 02: 417.42 ppm
May 01: 418.03 ppm
April 30: 417.31 ppm
April 29: 417.21 ppm
Last Updated: May 4, 2020

As I noted earlier today, the most recent weekly average set an all time record for such readings at 416.82 ppm.

New Weekly CO2 Concentration Record Set at the Mauna Loa Observatory 416.82 ppm.

I suspect climate change will be with us long after Covid-19 has become a memory of a nightmare reified.

[Wounded Bear]

1. It would take decades or longer to reduce atmospheric CO2 by meaningful amounts...

CO2 is a very stable molecule. It lasts a long, long time. It doesn't really break down naturally except by photosynthesis.

[Warpy]

2. It might be a year before decreased oil pollution is felt

from a dramatic enough lockdown worldwide to have us drowning in a glut of oil while people stay home and urban air becomes invisible for the first time in decades.*

Jet pollution is down, also. Only the coal fired electrical plants seem to be working at capacity. There's not even enough vulcanism to affect things.

Either readings are lagging behind current events or something else is at work and science had better start to look for possible explanations.

If there is an additional mechanism at work, some advice for our Canadian friends: that old log you never noticed before at your favorite fishing hole is an alligator. Fish somewhere else until h goes away.

*Referencing the old NYC joke, "I don't trust air I can't see."

[LonePirate]

3. I, too, am perplexed why the readings continue to go up despite the economy shutting down.

Maybe the planet is simply incapable of absorbing or transforming the carbon dioxide we’re still emitting. Or maybe there is a lag effect or a delay. Or maybe there are additional causes (deforestation?) that negate any reduced carbon emissions from humans.

[Warpy]

4. It might seem like forever to us, but this has only gone on for 3 months, at most

and the atmosphere is big, really big, so it will take time for any of this to affect it.

However, it they don't see a blip somewhere down the line, we'll know something else is going on.