Why too low?

Those homes aren't 'mansions' by most standards. But if you own a 1.5M home in central London you either bought it recently and therefore have money, or benefitted from big unearned housing market gains and could share some of that back with the state?

Fair, but it's a step into the dark either way, and the uncertainty under [more warming] might be larger than that under [less warming + SAI]

of course, but by my back of the envelope 'eventually' here means order 100,000 years.

1°C cooling ~ 10 Tg SO2 ~ 1% of current aviation ~ 0.03 % of global CO2 emissions ~ 1E-5 °C extra warming per year SAI

Lots of good reasons not to do SAI but the CO2 impact isn't one of them

Well said Dan! After a week spent with the inspiring early career SRM community and Operaatio Arktis folks, the contrast in values to Stardust couldn't feel stronger

Did Northern Hemisphere air pollution contribute to 70s and 80s Sahel drought? We think so, but we're still arguing about how much.

For the most important risks of solar geo, consensus would (hopefully) emerge, but slowly. Informed by observed climate, but still based on theory and modelling

The evidence we have, though, suggests SAI is not like these other ideas, being instead logistically feasible, effective and quite cheap.

We could be wrong on all three of these, of course, but honest debate about geoengineering demands that we grapple with that evidence

The SAI section bends over backwards to try to fit it into the same mould as the others (logistically difficult, expensive, and ineffective), but in doing so makes some surprising errors as well as being one-sided.

But the idea that further research into these is a waste of resources is crazy to me, when i think about what is at stake here.

Yes sea-curtains sound difficult, but so does building a sea-wall around Bangladesh.

Similarly for the ice sheet interventions. While those working on these have been the first to ackowledge that they are profoundly ambitious ideas, the Siegert et al study is a valuable and welcome critical perspective to help understand how and why these ideas would face challenges.

My impression is that sea-ice thickening and the ice sheet interventions are somewhere between implausible and just unlikely. The potential for sea-ice thickening to meaningfully impact global climate is often exaggerated, though, and its good to call this out

Glass beads for sea-ice albedo modification has always been an implausible idea - here's me in 2023 writing as much. I welcomed the decision of the Arctic Ice project folks to wind down their activities.

www.arcticiceproject.org/the-project/

agupubs.onlinelibrary.wiley.com/doi/full/10....

Not all geoengineering proposals are plausible, and we shouldn't waste time and resources on the implausible ones.

Siegert et al look at 5 (really, 6): sea-ice thickening, sea-ice albedo modification, sea-bed curtains, basal water removal from ice sheets, CDR via ocean fertilization, and SAI