Some of you will know about the workshop on climate sensitivity that's taking place this week at Ringberg in Germany. The participant list includes some big names in the science world, and will ensure a wide range of views on the subject.
You can read about the workshop at realclimate.org, or visit the website. You can also follow what's happening on Twitter, by searching #ringberg15. (There are some nuisance denier tweeters, but if you're on Twitter, you can just block or mute them and read what the scientists are tweeting.)
The workshop aims to get a better handle on climate sensitivity (and transient climate response), though I'm not all that optimistic that there'll be agreement on all counts. Here are the questions posed on the website:
I. Is the present range of TCR/ECS too narrow or broad and if so what is the case for changing it?
- physical hypotheses and story lines
- model and observational investigations, underlying mechanisms
II. How would we expect extremely sensitivities (either high or low ones) to physically manifest themselves?
- in terms of climatology, variability, trends and past changes
- in terms of projections
III. How strongly can observations (including palaeo) constrain sensitivities?
- how consistent are different constraints and what can be inferred from multiple constraints?
- do observations suggest models are missing or distorting key processes?
- what are the most promising prospects for reducing uncertainty in estimated ECS/TCR? How to facilitate these?
- any blocking points? Any evidence (or otherwise) that the problem should be addressed differently?
- are there specific ideas or mechanisms to be tested more collectively? Using more exotic models or data?
I've been reading through the papers - most of them have been made available for the workshop, though not all. They all make interesting reading. I found the upcoming paper by Steve Sherwood et al particularly interesting. It discusses "the new concept of adjustments, which are responses to forcings that are not mediated by the global mean temperature". From the abstract:
This concept, related to the older ones of climate efficacy and stratospheric adjustment, is a more physical way of capturing unique responses to specific forcings. We present a pedagogical review of the adjustment concept, why it is important, and how it can be used. The concept is particularly useful for aerosols, where it helps to organize what has become a complex array of forcing mechanisms. It also helps clarify issues around cloud and hydrological response, transient vs. equilibrium climate change, and geoengineering.Another paper by Joeri Rogelj et al is about "what to do" and discusses the impact of different sensitivities on risk and policy response. (Answer - not a great deal. We need to act now.)
Then there's the Stevens paper that got deniers and Nic Lewis a bit over-excited, which was suggesting that aerosol forcing may not be as negative as in some climate models and the "best estimate" of the IPCC. (Bjorn Stevens is also a co-author of the Sherwood paper I mentioned above. I suggest reading both papers because they complement each other.)
Click on the >>> to download the papers or go to the abstract.
- >>> Andrews, T. et al., 2015: The dependence of radiative forcing and ... , J. Climate, 28, 1630-1648
- >>> Armour, K. C. et al., 2013: Time-varying climate sensitivity from regional feedbacks. J. Climate, 26, 4518-4534
- >>> Caldwell, P. M. et al., 2014: Statistical significance of climate sensitivity predictors ... , GRL, 41(5), 1803-1808
- >>> Feldl, N., and G. H. Roe, 2013: The nonlinear and nonlocal nature of climate feedbacks. J. Climate, 26, 8289-8304
- >>> Huber, M. and Knutti, R., 2014: Natural variability, radiative forcing and ... , Nature Geoscience
- >>> Huber, M. et al., 2014: Estimating climate sensitivity and future temperature in ... , GRL
- >>> Lewis N. and Curry, J. A., 2014: The implications for climate sensitivity of AR5 forcing and ... , Climate Dynamics
- >>> Marotzke, J. and Forster, P., 2015: Forcing, feedback and internal variability in global temperature trends. Nature
- >>> Meraner, K., et al., 2013: Robust increase in equilibrium climate sensitivity ..., GRL, 40, 5944–5948
- >>> Merlis, T. M., et al., 2014: Constraining transient climate sensitivity using ... , J. Climate, 27, 7781-7795
- >>> Millar, R. J., 2015: Model structure in observational constraints on ... , Climatic Change, in press
- >>> Roe G. H., et al., 2015: The remote impacts of climate feedbacks on regional ... , Nature Geoscience, 8, 135–139
- >>> Rogelj, J. et al., 2014: Implications of potentially lower climate sensitivity on ... , Environ. Res. Lett.
- >>> Rose B. E. J., et al., 2014: The dependence of transient climate sensitivity and ... , GRL, 41
- >>> Schaller, N. et al., 2014: The asymmetry of the climate system's response to ... , JGR
- >>> Sherwood, S. et al., 2015: Adjustments in the forcing-feedback framework for ... , BAMS, in press
- >>> Shindell, D. T., 2014: Inhomogeneous forcing and transient climate sensitivity. Nature ClimateChange, 4, 274–277
- >>> Stevens, B. 2015: Rethinking the lower bound on aerosol radiative forcing. J. Climate, in press
- >>> Qu, X. et al., 2014: On the spread of changes in marine low cloud cover in ..., Climate Dynamics
Royal Society journals free to the end of March
From the Royal Society blog:
So what better way to mark the 350th anniversary of the world’s first science journal than to make all Royal Society content freely available, to everyone?
Yes, you read that right… readers can access our complete collection online, without the need for a subscription, between now and the end of March.