Not much point discussing solutions with people who won't even acknowledge the problem :doh
There's a lot of interesting ideas in this thread, but many of them seem to have an extremely narrow scope: Just one element of the long-term trajectory of portable energy supply.
The problem is the IPCC identified the wrong problem, the problem is energy.
By addressing the real problem with a solution compatible with existing demands, we can solve both the primary problem (energy)and the possible problem CO2.
Firstly, let's not forget that for most light and local uses there's every indication that electric vehicles can perform just as effectively (indeed, more energy efficiently) as their petrol-operated counterparts.
It will very hopefully be the case that artificial liquid fuels will eventually be cheaper than oil-based products.
Firstly, most vehicles are not electric, and it will be many years before they are. Rather than requiring people replace millions and millions of vehicles,
wouldn't it be quicker to change the fuel those vehicles use to something that does not add CO2?
Since we know both the wholesale price of electricity and the stated efficiency, we do not have to be hopeful about someday,
it actually has a price attached. If the wholesale price is $50 per Mwh, then oil above $95 a barrel would be unsustainable.
The reason it would be unsustainable, is the refinery operators, will use whatever process makes them the most profit.
Furthermore if the production of artificial fuels ends up using coal-generated electricity (ditto for electric vehicles), I imagine that anything less than 100% efficiency in the process would mean that it's simply increasing greenhouse gas emissions. That would be the likely consequence of refusing to come to terms with the reality of global warming and the need to reduce emissions, and promoting artificial fuels as a potentially carbon-neutral path forward while opposing any other facet of energy transition. Coal is cheap and abundant.
I think the source will almost have to be home Solar (sold at the wholesale rate)or Nuclear, because the economics do not support making a hydrocarbon fuel from a hydrocarbon fuel.
They already know how to make liquid fuel from coal, just not cheaply.
FYI Nuclear is quite a bit cheaper than fossil fuel electricity, at least according to US Government.
https://www.eia.gov/electricity/annual/html/epa_08_04.html
Fourthly, looking only at the supply of energy seems to me an extremely misguided approach: Improvements in efficiency of all sorts would mean less consumption and hence, usually, less cost to consumers. I imagine there's a lot of room for improvement in city planning, including better mass transit systems and foot- and bikeways.
No one said we should stop looking for improvements in efficiency, those have been ongoing and will continue.
We are capable of making net zero homes already.
If we can build on that and create net zero lives, why would we need to restrict where or how people choose to live?
Finally, with the possible exception of international shipping, it's important to note that I don't think it's necessary that government involvement in any of these areas needs to take the form of taxes or subsidies - which certainly have potential pitfalls as well as potential benefits. For example, instead of taxing coal power an option would simply be regulation requiring all new power plant projects meet zero-emission (both GHG and harmful particulate) standards, along with whatever improvements are feasible upgrades for existing plants.
I would rather the Governments let things die naturally, rather than regulating them out of existence.
regulations cause some form of black and grey markets, because they generate a possible profit gap to be exploited.
If things die on their own, there was no profit left to exploit.
Once again the real problem is energy! we simply do not have enough fossil fuels, to allow everyone on earth to live
a first world lifestyle. The approach I am discussing would provide a sustainable path forward, capable of supporting billions
of people at first world levels.
Part of the issue is that the best form of energy storage available (hydrocarbon) has been demonized to the point
the some people refuse to consider it.
The next closest contender for storing hydrogen is ammonia, which has been used as a fuel, but it is dangerous and smells bad.
Our current widespread demands, and infrastructure are setup to use hydrocarbon fuels,
making those fuels carbon neutral would be the fastest path to reducing CO2 emissions,
and in addition provide a path forward for Humanity.
P.S. in the long term, I could easily see fuel cell electric jets with hydrocarbon hydrogen storage.
if do right it, could double the range of existing jets.
