This just shows that "scientists" don't really know what's going to happen because they listened to propaganda.
I'm pretty sure the Sahara is being reclaimed because locals are forcing new vegetation growth. Something like 4000 miles of trees long and 10 miles deep were planted in an attempt to halt it. In some ways it did, but it also changed how the desert was advancing on land.
Sadly most of the trees didn't last, but it evolved how they run their irrigation to make what has lived, and what has sprouted on its own to survive.
Anyhow, with all what's been going on with the weather, that's also why they started calling into climate change, instead of global warming. Seems like summers are getting hotter, and winters are getting colder.
Long story short, both on the road passenger vehicles and commercial have done their part to clean up the air. I feel emissions are a necessary evil for us to deal with, but going practically zero is unachievable. What we should be going after is the real belchers of bs into the air, cargo ships, cruise ships, and airplanes. Especially personal air crafts. Just my 2¢