Leaf or Solar Cell plus Electrolysis
It isn't "we" anymore, it's "them". China and India produce far more carbon dioxide than does the US. Carbon dioxide levels are rising, and much of it is from human sources, but there's no proof that that's what's causing "global warming". Carbon dioxide absorbs far less heat than does water vapor. The big example is the real climate change that killed the Old Kingdom of Egypt and changed so much of the Mid East into the desert it is today. No manmade excess of carbon dioxide 4000 years ago
That doesn't make this new artificial leaf any less valuable. The only reason that solar hasn't completely taken off is that there is no efficient way to store the energy. Lithium batteries, despite billions being spent on research here, in Europe and in China, are still too inefficient in terms of energy storage.
The leaf, as described in this interesting article, seems to solve that problem by not generating ephemeral electricity, but rather by producing more easily storable hydrogen and oxygen. The question is, would it be more efficient to use regular solar cells to generate electricity and to perform electrolysis on water in two steps, as opposed to this new leaf, which seems to be able to do it one.
As to taking carbon dioxide out of the air – that's going to be first step towards humans controlling the climate. The problem is that what's good for one region of the planet might not be good for another. I once heard a Russian joke that he's all for global warming – think of how valuable land in Siberia will become!