Talk:Shared Socioeconomic Pathways

Reason for deletion nomination
The source webpage is re leased under a Attribution-NonCommercial-NoDerivatives 4.0 International license, which is not a compatible license. — Diannaa 🍁 (talk) 18:12, 14 September 2019 (UTC)

Contested deletion
This page should not be speedy deleted as an unambiguous copyright infringement, because the Carbon Brief website says "Published under a CC license. You are welcome to reproduce unadapted material in full for non-commercial use, credited ‘Carbon Brief’ with a link to the article."

However as I am not a copyright expert I have removed the SSP descriptions for now. --Chidgk1 (talk) 18:14, 14 September 2019 (UTC)
 * Attribution-NonCommercial-NoDerivatives 4.0 International license not a compatible license, because it does not allow commercial use or derivative works, and our license does. — Diannaa 🍁 (talk) 18:40, 14 September 2019 (UTC)


 * Oh I see thanks for explaining the difference.Chidgk1 (talk) 18:51, 14 September 2019 (UTC)


 * The CarbonBrief author has copied the narratives from Riahi et al. (10.1016/j.gloenvcha.2016.05.009), which has been released under CC-By-4.0. So if we credit the sections to Riahi et al, we should be fine. --DeWikiMan (talk) 19:51, 7 December 2020 (UTC)


 * In other words, it's not copyright violation, just plagiarism! I've added quotation marks to make clear they are direct quotations. Adpete (talk) 02:50, 29 March 2023 (UTC)

This article is confusing me
1) I don't understand the second part of the second sentence "with different climate policies". I am not an economist but don't some of the SSPs have different climate policies by definition? For example SSP5 says "competitive markets" so does that not imply that fossil fuel subsidies have been abolished, and isn't that part of a climate policy?

2) Environmental pricing reform does not seem to be mentioned in any of the scenarios but wouldn't that make a big difference? For example taxing local air pollution is not primarily a climate policy I guess.

3) The graph has 2 lines for SSP1 but none for SSP4 and the numbers after the SSP number are not explained.

Could anyone make it a bit easier to understand? Chidgk1 (talk) 17:54, 9 February 2020 (UTC)


 * 1) As far as I understood it, a SSP does not comprise any climate policies, but focuses on the socio-economic parameters only. Any cimate policy comes on top and results in a bundle of emission pathways within a given SSPx family.
 * 2) If it is part of the relevant literature, mechanisms that drive as a secondary effect the emissions down can be added. If not, SPPs shall be described here in a way as they are used by the experts from IPCC et al.
 * 3) Yes, indeed. It seems that the group which developed the SSPs invented these 5 families of scenarios, which were then selected to explain different emission pathways. Obviously, the intention of the group was to present 5 scenarios, which were mostly known by the experts in the field, the professional media and the interested general public. If you compare the former RCP y.z and the new SSPx-y.z you can see that 6.0 morphed into 7.0 and that below 2.6 a new one 1.9 was invented to cover the 1.5 °C goal. The hard data which goes into the climate models is the amount of GHG emissions, which results in the radiative forcing. Obviously, it was easier to assign 1.9 and 2.6 to SSP1 and therefore, none was left for one of the remaing four SPPs. In the end, SPP4 (Inequality - A Road Divided) was not used. --Gunnar (talk) 11:55, 29 August 2021 (UTC)


 * Ah sorry I just made edits today before I noticed this talk page. So I have messed up the article. Do you think we should simplify the article by getting rid of all the AR5 stuff? Chidgk1 (talk) 11:06, 3 October 2021 (UTC)


 * For those mishaps, the redo button is very helpful. Regarding "AR5 stuff" I don't know what you mean, as it is AR6 stuff and the sixth assessment report basically uses the SPPx-y.z notation which is equivalent to the RCPy.z scenario ID from AR5. --Gunnar (talk) 22:25, 3 October 2021 (UTC)
 * Re 3) The graph is misleading (as evidenced by your comment, for example) and I suggest deleting it. It doesn't really add much of value to the article and appears to be making the incorrect(!) impression that certain SSP scenarios lead to certain radiative forcing outcomes, which is incorrect. In fact, for each of the SSPs, many scenarios (from different model teams, using different specific assumptions) exist that result in 2.6mW^-2 or 3.5Wm^-2 forcing, and for most SSPs several to many scenarios exist for 1.9Wm^-2. An uninitiated reader looking at this graph would not get that impression. In the article, there's a table from the AR6. The important column there is the "Scenario" column, not the SSP column. The numbers in the remaining columns are based on the scenario choice, not the SSP choice and it would be wrong to read the table that the chosen scenarios are somehow a representative of the SSP under which they have been modelled.
 * Again, I suggest deletion of the radiative forcing/CO2 concentration chart. krueschan (talk) 07:40, 15 March 2022 (UTC)

Likelihood of emission scenarios
The full report of IPCC AR6 WG1 on The Physical Science Basis, Chapter 1: Framing, context, and methods, page 1-109 says in paragraph 1.6.1.4: "In general, no likelihood is attached to the scenarios assessed in this Report." - Is it true that the full WG1 report (I didn't read all the 4000 pages) does not assess the probability of the different 5 scenarios which result into a radiative forcing at the year 2100 (1.9; 2.6; 4.5; 7.0; 8.6)? Will it be covered in one of the other WG reports? --Gunnar (talk) 13:28, 29 August 2021 (UTC)


 * It's impossible from a scientific standpoint to assign likelihoods to the scenarios since nobody has figured out yet how to predict the future. We simply don't know what choices future societies will make and all these scenarios represent all but one set of such choices. Of course, they are still valuable since they will allow us to explore the implications of this particular set of choices and if we like the implications, we can try and make similar choices and if we don't like the implications we can try and avoid making those. (and, typically using many runs of computer models, we can assign likelihoods to specific outcomes that a certain set of choices, i.e. a scenario, will yield, which is the likelihoods you're used to seeing, but those are likelihoods of a given scenario to result in certain outcomes (e.g. a 1.5°C temperature increase), those are not th likelihoods of that given scenario coming to pass - because, again, the skill of future telling would be required to do that) krueschan (talk) 07:47, 15 March 2022 (UTC)

Does anybody else know other assessments on possible futures in regard to emission scenarios and the availability of non-renewable fossil fuels? --Gunnar (talk) 16:02, 29 August 2021 (UTC)

I found this here: Impact on climate change: IPCC scenarios (Chapter 10, p. 83ff in Laherrere: Estimates of Oil Reserves, EMF/IEA/IEW meeting at IIASA, Laxenburg, Austria 2001. which pointed out already 20 years ago that most of the IPCC emission scenarios are not based on producible fossile fuels. --Gunnar (talk) 07:42, 30 August 2021 (UTC)

And another one: Kjell Aleklett: Reserve Driven Forecasts for Oil, Gas & Coal and Limits in Carbon Dioxide Emissions, Discussion Paper No. 2007-18, International Transport Forum / OECD, December 2007. "First we can conclude that CO2 emission from burning oil and gas are lower then what al the IPCC scenarios predict, and emission from coal is much lowers then the majority of the scenarios. IPCC emission scenarios for the time period 2020 to 2100 should in the future not be used for climate change predictions. It’s time to use realistic scenarios." --Gunnar (talk) 17:55, 5 September 2021 (UTC)


 * Not sure we need these old sources as ref 20 from 2020 seems to cover your point I think. Chidgk1 (talk) 08:22, 15 March 2022 (UTC)


 * The global coal production shows a plateau in the last decade, cf. IEA 2021, while Rutledge 2011 explains the riddle about where IPCC got its coal for its most severe emission scenarios. --Gunnar (talk) 14:31, 26 August 2022 (UTC)

Context needed
This article needs context. Specifically, who authored these scenarios, and when? Adpete (talk) 06:10, 29 March 2023 (UTC)


 * Yeah, this is not immediately apparent at all. Mechachleopteryx (talk) 11:39, 11 April 2023 (UTC)