Thanks for that paper Johannes, it was mildly reassuring to read.
Liu and Raftery (2021) show that countries must increase their decarbonization rates by 80% relative to Paris commitments to limit warming to 2°C by 2100. Similarly, if the pace of global decarbonization fails to keep up with IEA’s (2020) STEPS projections (decarbonization has exceeded IEA projections in recent years; see IEA 2019, 2020), we find that several scenarios having greater than 3°C warming by 2100 become plausible (Fig. S4B).
One thing I was struck by is this section in the discussion (bold emphasis mine) is that an 80% increase in decarbonisation rates relative to Paris commitments seems quite large and slightly ironically, not very plausible. Is there any evidence that countries are making or planning to make such a radical step up in their decarbonisation, as it seems like their policies don’t even reflect this?
Paris Agreement targets are till 2030, so I’d be less deterministic wrt what is possible till 2100, looking at Liu and Raftery it sounds as though they are just extrapolating current trends.
In worlds where we would keep temperature <2C by 2100, I would expect large structural breaks, not getting there by trend extrapolation/incremental steps (e.g. decarbonization getting really cheap and easy at some point, or negative emissions becoming very affordable and scaleable etc.).
Thanks for that paper Johannes, it was mildly reassuring to read.
One thing I was struck by is this section in the discussion (bold emphasis mine) is that an 80% increase in decarbonisation rates relative to Paris commitments seems quite large and slightly ironically, not very plausible. Is there any evidence that countries are making or planning to make such a radical step up in their decarbonisation, as it seems like their policies don’t even reflect this?
Paris Agreement targets are till 2030, so I’d be less deterministic wrt what is possible till 2100, looking at Liu and Raftery it sounds as though they are just extrapolating current trends.
In worlds where we would keep temperature <2C by 2100, I would expect large structural breaks, not getting there by trend extrapolation/incremental steps (e.g. decarbonization getting really cheap and easy at some point, or negative emissions becoming very affordable and scaleable etc.).