Why would there be a slight increase over the last few months, when electricity use is down in the US and several other countries, and driving and public transportation surely are too? There are of course many variables and many things going on at once, so maybe no one knows. The only idea that comes to me is that we're on the border of short-term El Nino conditions (ONI of about 0.5), and El Ninos increase atmospheric CO2 because they bring heat the atmosphere, and especially the tropics, which causes more drought and fire there that kills plants that were taking up CO2. (Though it's not that simple.)
For example, here's the 52-week change in atmo CO2 over several decades:
The strong El Ninos of 1997-98 and 2015-16 clearly stand out.
Any other ideas?
PS: I saw a tweet the other day saying if a blood alcohol level of 0.08% is enough to impair driving and get you arrested, how can a CO2 level of 0.04% be considered a meaningless trace gas?