Update SSPs

[MarkMDekker]

https://data.ece.iiasa.ac.at/ssp/#/workspaces

[MarkMDekker]

Maybe nice to see for @EHooijschuur . For the NLD, the population (and also in terms of fraction of world) drops for the future:

And the GDP also drops, but only in the long run also when computed as fraction of the world:

So we can expect:

• It seems that GDP per capita increases a bit, at least when compared to the rest of the world (as population drops faster), but over time. This may 'loosen' AP a bit, and in turn also GDR.
• Current population levels are actually higher as you can see near 2020, but not the fraction of the world. This may mean that PC and PCC become more harsh for NLD.

(This is SSP2)

[MarkMDekker]

(I'm currently working on a pull request to implement these numbers)