The speakers were:
Adam Bauer (Univ. of Chicago): "Learning Climate Sensitivity from Future Observations, Fast and Slow"
Moritz Günther (MPI-M): "Heating the land cools the Eastern and Equatorial Pacific"
Clare Singer (Univ. of Colorado, Boulder): "Southern Ocean Clear-Sky Brightening From Sea Spray Aerosol Increase Drives Departure From Hemispheric Albedo Symmetry"
00:37:15 Karsten Haustein (he /him): @Camille Hankel Is the long-term amplification factor (3 for Arctic, 5 for Antarctica iirc) the same in other models? Or more generally, how robust is it?
And btw, great talk indeed!! 🙂
00:37:58 Matt Luongo (he/him): @Camille Hankel — Any sense of why every single ramping rate has this interesting Antarctic feature? Each one seemed to have the same salting but at a different time, maybe suggesting its not an AMOC feature since those were so different across ramping rates.
00:38:00 Gavin Schmidt: Also in this paper: Mitevski, I., Y. Dong, L.M. Polvani, M. Rugenstein, and C. Orbe, 2023: Non-monotonic feedback dependence under abrupt CO2 forcing due to a North Atlantic pattern effect. Geophys. Res. Lett., 50, no. 14, e2023GL103617, doi:10.1029/2023GL103617.
00:38:33 Andrew Williams: @Camille Hankel , great talk. Following on from Gavin’s question, is the final global-mean dT similar in all these runs?
00:40:52 Camille Hankel: Indeed, I thought it might related not to AMOC weakening but to AMOC recovery (which occurs in all ramps), but in fact in some different runs I did for a different project where the AMOC does not recover, you still get this feature. So I think it’s more likely to be related to AABW changes, which probably continue evolving over many centuries due to slow Antarctic warming
00:41:32 Camille Hankel: Final dT is indeed, the same for all experiments!
00:41:58 Andrew Williams: Reacted to "Final dT is the same..." with 👍
00:45:44 Camille Hankel: Replying to "@Camille Hankel Is t..."
Our final Arctic amplification factor is similar to the range produced by other models (2-4K), our Antarctic amplification factor is higher than other model, but at year 1000 (when most other models stop) our model and other models tend to agree (around 2K). So the difference between CESM1 and other models for the Antarctic seems to be attributable to the abrupt warming event that we get (which give ~2.5K of extra warming). Thank you!!
00:46:14 Camille Hankel: Reacted to "Also in this paper: ..." with ❤️
00:46:27 Karsten Haustein (he /him): Reacted to "Our final Arctic amp..." with 👍
00:59:31 Tim Merlis: Following on Andrea’s talk, there’s a literature about the efficacy of local forcing that is consistent with the headline of ‘a local perturbation in the tropics does less than perturbing in a more globally uniform way’. I’m thinking of Rose et al. 2014 GRL, Kang & Tie (also 2014ish), Bosong Zhang and Ming Zhao GRL 2023. Likely Malte Stuecker’s work perturbing CO2 concentration in local latitude bands is also consistent with this.
01:01:10 Tim Merlis: Kang & Xie (autocorrect)
01:06:38 Vince Cooper: Hi @Andrea Salazar , I enjoyed your talk— could we interpret the difference in feedbacks (-1.2 W/m2/K vs -0.8 W/m2/K) in the cloud locking experiment as primarily the result of removing the stratocumulus feedback? Since those clouds are locked, a large positive feedback is removed, so the experiments show a much more stable feedback parameter. Is that aligned with your thinking?
01:10:16 Andrea Salazar: Replying to "Hi @Andrea Salazar ,..."
Hi Vince, love this question. It’s a good point—the stratocumulus cloud feedback is a strong positive feedback and by manually performing it, we are essentially “removing” it from the climate’s response. To try and constrain the effect of this, we calculated the global feedback parameter in the CO2 forced case by ignoring the stratocumulus regions and found ~10% reduction in climate sensitivity. Not enough to explain the nearly 50% change from the localized forcing, but definitely a part of the story.
01:12:03 Vince Cooper: Reacted to "Hi Vince, love this ..." with 👍
01:13:01 Gavin Schmidt: Putting in a plug for including ice sheet meltwater in upcoming CMIP7 runs! Schmidt, G.A., K.D. Mankoff, J.L. Bamber, D. Carroll, D.M. Chandler, V. Coulon, B.J. Davison, M.H. England, P.R. Holland, N.C. Jourdain, Q. Li, J.M. Marson, P. Mathiot, C.R. McMahon, T.A. Moon, R. Mottram, S. Nowicki, A. Olivé Abelló, A.G. Pauling, T. Rackow, and D. Ringeisen, 2025: Datasets and protocols for including anomalous freshwater from melting ice sheets in climate simulations. Geosci. Model Dev., doi:10.5194/gmd-18-8333-2025.
01:15:25 Nadir Jeevanjee: Thank you all
01:15:30 sarah: Thank you