One thing i don't understand is how the CO2 concentration in the atmosphere is spread around the world.

Intuitively, i assume it's higher in places like China? Then thins out from there?

And how does it translate in terms of localised effects where concentration is higher - or doesn't it work like that?

https://arstechnica.com/science/2019/02/striking-study-finds-a-climate-tipping-point-in...

"A new study led by Caltech's Tapio Schneider may have identified a disturbing hysteresis in Earth's climate—a shift in cloud patterns in response to warming that could quickly heat the planet much further."

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"Up to about 1,000 parts per million, there were no major surprises. Things got around 4°C warmer and numbers changed for things like water vapor and cloud altitude. But the cloud deck generally looked familiar.

At about 1,200 parts per million, however, the simulated clouds suddenly dissipated. And without that shade reflecting sunlight, the world warmed another 8°C."

One question that this raises is, what might cause the CO2 to rise to 1,200ppm? According to the article, it's now at 400ppm:

"Are we doomed to see this play out soon? There's a good case to be made for, if not optimism, at least holding off on pessimism. It would take around a century of continued emissions growth to hit the equivalent of 1,200 parts per million CO2. Even the emissions-reduction pledges that have already been made can prevent that."

The article goes on to basically raise more questions than it answers, but that's worrying, really. Basically it's saying that there are all sorts of events that have happened in the distant past, are happening now, and could happen theoretically, none of which we really understand.