In an ideal world, we would reach net zero in time to prevent that. This is the only long-term solution. But what if, in a decade or two, every projection says we won’t? Are we to chastise the rest of humanity, say “you could have prevented this the proper way!”, and let the dominos begin to fall?
Geoengineering, if the science is proven, should only act as a last resort to prevent such a domino effect. It would symbolise a profound failure of our species. But surely, if we realise we failed, this risky Hail Mary is better than not acting?
The risks of another massive human intervention into the atmosphere are obvious. Furthermore, geoengineering risks giving many nations an excuse to keep burning fossil fuels. Nobody has the right answers yet and everybody sensible agrees we need to do everything we can to reach net zero first.
But what if we don’t?
It is of course possible that both technological and social approaches will prove insufficient, and we'll go well beyond the "safe" level of global warming.