Thread by @hausfath

There is a pretty strong claim here that anything without a 50/50 chance of avoiding 1.5C is "not compatible with the Paris Agreement". Well-below 2C was the main Paris goal with an aspirational goal of limiting warming to 1.5C, but this seems to conflate the two a bit.

https://twitter.com/CA_Latest/status/1456672849507258370

Here is the actual language of the Paris Agreement: "Holding the increase in the global average temperature to well below 2C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5C above pre-industrial levels"

Of course, "well-below 2C" is not particularly precise. While some have defined it in the context of a 2/3 chance of avoiding 2C warming (e.g. in RCP2.6 or SSP1-2.6 scenarios), others have defined it more ambitiously (e.g. 90% chance of < 2C, which is effectively a 1.5C scenario)

But if this were the intention of the framers, why frame the 1.5C target as aspirational? Why not just say "pursue efforts to limit warming to 1.5C thereby ensuring that warming very likely remains below 2C" rather than separating them out as separate targets?

The bigger issue here, of course, that these long-term net-zero commitments are, in essence, just countries adding a bit more specificity to the Paris agreement goal. Actually getting from here to net zero – adopting policies putting countries on that path – is the real challenge

So enhanced long-term ambition by individual countries is a good thing, but we should not pretend that just because a leader commits to do something in 30, 40, or 50 years means that countries will necessarily follow though on those commitments.