I'd be happy to be proven wrong, but I think natural resource constraints and tribalism / nationalism are the greatest chronic threats we face.
Energy tech and communications tech try to solve these, respectively; most funding, research and commercialization appears to happen here (although most deployment happens globally).
I've been studying where things are happening from my admittedly skewed vantage point for quite a long time. It does still seem that the vast majority (>60%) of activity is happening in the bay area.
I don't think SV is at the forefront of energy tech, don't have any figures to hand, but I would put Germany way ahead of SV.
Communications tech, yeah maybe, but it is very well dispersed now. Social change created by this? Less so, the US is trying to reinforce the existing consumer society through better advertising. Much of the rest of the world is experimenting with using new technology to help change society, from the Arab Spring to M5S and the Pirate Party and so on.
This is one of those occasions where it's worth checking the poster's profile. Danielle Fong is "cofounder, chief scientist, lightsailenergy.com" and probably does know a lot of people in SV working on energy tech.
There is little need for better energy tech at this point, it's all a question of deployment.
Edit: That is to say wind and solar can both be cheaper than coal right now depending on location and how you calculate the cost of money etc. Which means we are over the tipping point and it's just a question of how much and how quickly to invest not the need for some great breakthrough.
It's not possible to economically power the world with non-fossil fuel based sources based on current prices. We are between a factor of 2 off, optimistically, and more likely a factor of 5 off (floored by extraction and processing costs.)
I don't know where you got your data or how you're doing your analysis, but you're incorrect on this one.
That said, scaling things up quickly is a hard problem but slow things down and many problems go away. Realistically, rather than transporting electricity to industry a lot of industry is going to move to where there is cheap power. Also, transportation is a separate issue boats and airplanes are not going to be 'green' any time soon.
What makes America unique and strong is that few other places attract the amount of international talent that SF, and the US in general have. To my knowledge there is no other city in the world that attracts the amount of international talent that SF or NYC can. That with some of the best universities in the world, with many of them in California, put California, and SF, in a good position for many years to come.
Having said that, the world is changing. And we will see other inovation hotspots emerge, but I truly believe without diversity in people, it is harder to have diversity in thought , which can inspire innovation.
Given the level of attraction of SV, the number of talented people from outside the US would be much greater if it wasn't for the way the US government treats foreigners. If the government doesn't become more receptive to foreigners it is quite clear that SV will never grow to its full potential.
Energy tech and communications tech try to solve these, respectively; most funding, research and commercialization appears to happen here (although most deployment happens globally).
I've been studying where things are happening from my admittedly skewed vantage point for quite a long time. It does still seem that the vast majority (>60%) of activity is happening in the bay area.