Ask HN: Now that CO2 levels are down, can we see if CO2 causes global warming?

The Chinese virus caused an almost complete stop of all activities, at a level that would be impossible to achieve in a normal situation.

It's already been noticed that CO2 levels have decreased significantly.

Will we be able to observe temps and see if there is definitely a relation between CO2 and global warming, or will this not be possible?

I would think that this is a one-time opportunity.