What's "unrealized externalities"? What an oxymoron.
Maybe a poor way of writing it; I'm not an economist. I mean, an externality that is not immediately obvious to the average Joe.
For example, they might not associate city traffic or coal pollution with increased rates of childhood asthma. The cost of this is on Joe, not on the producer of the pollution, so it is an externality. And it is unrealised, because Joe may not associate it immediately as causing it.
Of note is that asthma cases are significantly higher in city neighbourhoods; I wonder why?
As to externalities, everything has its externalities. Your very existence has a negative externality on the environment, this forum, and the rest of humanity.
What are you going to do about it?
Nothing. Really, there is very little I can or want to do about it. However it is possible to replace coal power with nuclear, which I am personally in favour of. Nuclear waste is still a concern but future reactors can run on the waste of older generation reactors. The problem is, there is an enormous amount of red tape regarding nuclear reactor design that the industry is too slow to adapt. It is now far more expensive per lifetime MWh to construct a nuclear power plant over a coal or nat gas power plant hence why they are rarely built these days.
As far as safety is concerned, nuclear is extremely safe, but like airline disasters, when it goes wrong, it can go really wrong. This makes promoting nuclear a big PR problem. As far as I am concerned, Greenpeace's anti-nuclear stance is not helping and I wish they could see the big picture. There is no current practical level of grid storage that could support a pure solar/wind solution that they seem to promote. In the mean time, nuclear can provide the necessary base load.
Personally I think gen 3/4 nuclear + wind + mild solar is the way to go in the UK, with low-waste nuclear representing about 75 to 80% of the contribution. Where possible geothermal & hydro can be used, location dependent.
With all the coal kills FUD it's useful to have a more balanced perspective. Fossil energy improved any aspects of our lives including infant mortality. Look at the big picture.
I agree that fossil fuels have been very beneficial to our economy and development as a species. Enormously beneficial in fact. But that has come at a huge cost to us and future generations. We have reached a level of technological development at which we can change this and make it better for everyone.