If you don't have a feel for the level of carbon price that's needed to make major change then $100 is a great rule of thumb.

Working in oil and gas, I know that our industry would make major changes if the global carbon price for scope 1 and 2 emissions was $100/ton. And if scope 3 emissions were included then I suspect oil and gas production would drastically decline, and probably use CCS as the norm.

The current average price put on all emissions in the world comes out at about $3.

In case you're thinking "how could a global carbon price of $100/ton possibly be affordable?" the answer is that $100 for every ton of CO2 emissions in the world is 4.3% of world GDP. And that money doesn't disappear of course, it's simply a transfer from polluters to... whoever you like.

And of course the economic benefit of not destroying the planet is nice.

Notably, one of the world's highest carbon prices is in Sweden, a location that would do just fine with a bit of global warming.