From previous discussions I've seen on pollution, but possibly not CO2 specifically, the global shipping industry is one of the bigger contributors. While we may have driven and flown less in the past year I'm pretty sure we didn't buy significantly less so there are still lots of ships out there.

Concrete production also takes a lot of energy. Based on the current costs of other building materials in North America I doubt we've slowed that down either.

Even if everyone in the top global 1% was driving electric cars right now we'd still be contributing a lot to CO2 emissions in other ways.