Climate change? We have literally changed the climate for the entirety of humanity's future unless we devise a system, whose energy requirements would overshadow practically anything we have ever invented and whose workings we still don't understand, and even so its impact would take decades, at the very least, to be felt.
Yep, found it: https://en.wikipedia.org/wiki/Iron_fertilization
If history is any indication, fertilizer runoff from rivers causes anoxic events in the ocean. That is shit is not to be fucked with; you can trivially destabilize an ecosystem and destroy it, as has already happened in many places.
Researchers from the GEOMAR Institute of Marine Biology have seeded the oceans in the southpolar sea with iron in large amounts.
Yes, a huge algae bloom happened – but also a huge growth of animals eating the algae, etc.
The end result was no CO2 being trapped, but fishers in South Africa had a good year.
So yes, air pollution is not only more important, but also easier to fix.
If anyone disagrees, go visit one of these cities. A few days of burning nasal passages and you probably won't be able to pay much attention to the decades-distant consequences of climate change.
The tradeoffs tend to be in smaller fixes anyway. With diesel engines, there's a point where you may have to choose between more CO2 and fewer particulates, or more particulates and less CO2. But obviously both will be improved greatly if you replace that with an electric motor and batteries charged by CO2-neutral energy.
Another issue is that agricultural and sea food products sourced from polluted nations may carry the pollution with them, needing increased monitoring of imports.
> The question poses a false dichotomy.
Eh.. assessing relative importance does not present a dichotomy, false or otherwise.