This one rule accomplishes the following:

1. best kind of ‘cap’ on new coal plant emissions – ZERO.
2. allowing sequestration or offsets as safety valve sounds less drastic than a total ban on new coal plants. Yet it’s still a drastic enough action to match the dire circumstances.
3. prices ‘externalities’ by raising the average cost of electricity. Without a direct ban on coal, it still steers the market away from using more coal.
4. marginal costs for new plants can be averaged in with costs for existing power – for a gradual impact to consumers
5. no direct price increases as with a carbon tax. therefore politically easier to advocate
6. stimulates the market for renewables and efficiency, both indirectly with the price increases for coal-fired electricity, and directly with offsets.
7. a relatively simple measure, both to advocate for and to administer.
8. sets stage for further improvements – “new coal” with sequestration becomes a demonstration for what’s technically feasible
9. utilities using new coal become a possible ally to clean up “old coal” of its carbon b/c they are competing for market share.
10. if sequestration isn’t ready yet, many offsets (efficiency, reforestation, some renewables) are

another, not related, point:

why is variability of supply supposedly such a killer for solar and wind options?

The usually posed alternatives of “baseload” coal and nuke have to cope with variable demand by using natural gas peaking plants. so, variable supply sources like wind and solar will likewise have to use gas as backup and gap-filler. Whichever way you go, gas is the likely gap filler until or unless there are cheaper storage methods.

Gee, didn’t they make the same claims for first through third gen nukes?

Over the past 30-40 years we have globally moved billions from the countryside where they had more or less sustainable lives to the global urban slums where they are dependent upon fossil-fuel intensive industrial agriculture and an economy based upon globalized, transportation intensive trade.

That same sort of decision is replicated time and time again in the choices we make about economic organization.

How many wedges from re-ruralization? How many wedges from eliminating the WTO?

Larry,
My point is that people had perforce gotten adapted to $4/gal gasoline. If we can’t act to hold the effective price that high then there is no hope of acting on the kind of massive program advocated here to hold CO2 to 350 or 450 level.
I think the new administration and congress will follow your thought process, which will prove my point, so we only have a few months to wait for an answer.

Shouldn’t there be at least one wedge from carbon sequestration? Not capture from power plant stacks, which seems to me to be futile, but charring and burying fallen trees or even felling and replanting trees. There are undoubtedly ways of sequestering without charring that would keep the carbon out of the atmosphere for long periods of time.

The economy is visibly shrinking, and noone can yet see the bottom. We’re about to get a look at a world in which we consume a lot less, and as one consequence, emit less C02. Let’s see how we like it.

The US auto industry may be done anyway, but a significant carbon tax now would surely finish it off, and quick. I’m not ready to speed its death. Now is not the time for a carbon tax.

If those are politically infeasible I wish you good luck when you try to pass legislation to allocate WW2 levels of spending toward this project for decades.

Why not push for something clearly doable as a first step. For instance, there is no way that consumer gasoline prices should have been allowed to drop from $4 as they have, and they should not be allowed to continue dropping. The very first thing to do is to slap on a 50 cent tax per gallon and include a proviso that the tax will grow steadily for the indefinite future so people and businesses can very clearly see the need to move toward more efficient vehicles.

If we can’t politically do that we may as well all get used to the idea of warmer temperatures.