I’d like to hope that PVs and other renewables might be cost competitive sooner rather than later so prizes offered for achievement of milestones with renewable energies and fusion would suit me fine, as would a carbon tax to pay for them, and an increase of funding of clean energy research generally. Renewables haven’t had the kind of military levels of spending tossed their way that nuclear enjoyed for decades, and it’d be nice to see peaceful, clean energies given support like that this millennium.

No, emissions are not continuing to “rocket skyward.” That’s merely an artifact of the fact that the first graph starts in the year 1750. (If the graph started at 1000 AD, it would REALLY look spectacular! )

If you go to Figure 1 of my website:

http://markbahner.50g.com/what_will_happen_to_us.htm

…you’ll see that CO2 emissions were indeed “rocketing skyward” from 1950 to 1960 and from 1960 to 1970…with increases of more than 50% per decade in both those decades.

But the percentage increases have dropped off significantly (15 percent from 1980 to 1990, and 6 percent from 1990 to 2000). The increase for 2000 to 2010 will probably be in the neighborhood of 10 percent (i.e., 1 percent per year). At an increase of 1 percent per year, it will take ~70 years for CO2 emissions to double from their current value.

But in fact, it’s not likely that emissions of CO2 will *ever* double from their current level.
This will probably never happen in part because of the reasons that I’ve already mentioned:

1) energy efficiency (including development of hybrids and later fuel cells for transportation, and fuel cells for residential electricity and heating),

2) methane hydrates,

3) photovoltaics, and

4) fusion.

In fact, the most likely scenario is that emissions will peak at 20-50 percent above their current values sometime prior to 2050, and then will begin to decline.

“But unless other environmental externalities can be costed into the price of those fossil fuels they’ll remain less expensive than either nuclear or renewable powered hydrogen production for a very long time,…”

Please define, “very long time.”

The Department of Energy’s Energy Efficiency and Renewable Energy Laboratory projects that photovoltaics will be competitive with fossil fuel electricity circa 2015-2020:

http://www1.eere.energy.gov/ba/pdfs/39684_app_D.pdf

Further, *operating costs* for nuclear fission plants are already lower than for fossil-fueled plants (coal, gas, or oil). The place where coal, gas, and oil plants are less expensive than nuclear fission plants is the capital cost and disposal of waste.

And no controlled nuclear fusion process has even achieved break-even energy production (so essentially, the “cost” is infinite).

In summary:

1) Photovoltaics are projected to be competitive circa 2015-2020, and some tax on “externalities” of fossil fuels is unlikely to accelerate that schedule (unless, possibly, if ALL the revenue was dumped into photovoltaics development),

2) Nuclear fission is already compatible in operating cost, and reductions in capital cost (e.g. easier licensing) and the cost of waste are the main items of cost for nuclear fission,

3) Nuclear fusion is essentially “infinitely costly.” So fossil fuel taxes wouldn’t help there either (unless the money was dumped into development of fusion).

To me, it seems much better to offer technological prizes for development of fusion and photovoltaics (and make licensing and disposal of nuclear waste less costly), if the goal is truly to increase those technologies’ inputs to the energy mix.

Of course the reason for preferring the more hydrogen rich fossil fuels has been their cost effectiveness as well as their better environmental performance, in particular that they leave more of our urban air breathable. It’s breathable today in the developed world thanks to government regulations. But unless other environmental externalities can be costed into the price of those fossil fuels they’ll remain less expensive than either nuclear or renewable powered hydrogen production for a very long time, leaving the hydrogen economy but a gleam in your eye. So Ausubel’s work is interesting and useful but history is not a roadmap to the future, only part of the grounds on which we must make our plans (if we’re to plan at all).

There’s no question that we have burned progressively lower carbon-intense fuels. However, there’s no guarantee that will continue: we will be out of natural gas in a few decades and countries like China and India have lots of coal, which they are certainly going to burn.

I think we all agree that we need alternatives, and that the world is heading in that direction already, albeit slowly. The the real question is: from a policy standpoint, how do we make sure that the transition to alternative energy occurs as quickly and efficiently as possible? My judgment of the answer: by deploying incentives beyond those which the free market can provide. In my opinion, something like a carbon tax will make the transition occur faster than just leaving it entirely to the free market.

Regards.

By “decarbonizing,” I meant that the ratio of carbon to hydrogen in the fuels being burned continues to go down. (And the ratio of carbon to hydrogen will approach zero by the end of this century, if not sooner.)

See my comments to Kevin Vranes, above.

“But I don’t even need to know that to know that your counterassertion is wrong, because you don’t actually refer in it to what I said (which was about the “market”, not “the world”).”

As I’ve noted, the world has switched from wood to coal (a significant reduction in carbon atoms per hydrogen atom), and coal to oil, and oil to natural gas…all without government mandates that such switches be done.

It’s silly to think that the U.S. and world economies won’t eventually be hydrogen economies, regardless of whether governments produce any mandates.

Yes, I guess I should have made that more clear. As Jesse Ausubel showed in other work:

“Wood is made of much cellulose and some lignin. Heated cellulose leaves charcoal, almost pure carbon. Lignin has a complex benzenic structure with an H:C ratio of about 0.5. Combining the pure carbon of cellulose and the 0.5 ratio of lignin, wood with 20% lignin effectively has an H:C ratio of 0.1. Said differently, wood weighs in heavily at ten effective Cs for each H. Coal approaches parity with one or two Cs per H, while oil improves to two H per C, and a molecule of natural gas (methane) is a carbon-trim CH4.”

http://phe.rockefeller.edu/BrainNotChange/

The world (i.e., the market) has “decarbonized” from wood to coal (10:1 to 2:1, C/H ratio), and coal to oil (2:1 to 1:2, C/H ratio), and oil to natural gas (1:2 to 1:4, C/H ratio)…all without any government mandates that the world decarbonize. It’s silly to think that this process will only continue with government mandates. As I noted before, by the end of this century, the world will be in a “hydrogen economy.” That means that CO2 emissions will be below levels that cause rising atmospheric CO2 concentrations…regardless of whether or not there are government mandates.

“And as the output/carbon used ratio gets better and better, what happens? Suddenly carbon-burning technologies are well within the reach of “developing countries” with very large populations, which means even more carbon used in sum.”

If you’re thinking that carbon used will continue to rise throughout the entire century, that thought is very strongly contradicted by available evidence. (If you’re thinking that carbon used will remain will rise by ~1 percent per year for the next couple of decades, before declining, then I agree.)

Here is a graph of CO2 emissions per capita in the world, from 1950 to the present. You can see it went up from 1950 to 1970, but since ~1970, it has been almost perfectly flat.

http://cdiac.ornl.gov/trends/emis/glo.htm

It’s *possible* that the curve will begin rising again, but it’s very unlikely. Technological history says that it will remain approximately flat for a while longer (my guess is 0-20 years), and then begin to *fall*…not rise.

Why won’t per-capita CO2 emissions continue to rise throughout the 21st century? Four potential reasons (in order of their penetration of the world energy scene, over time): 1) Energy efficiency, 2) methane hydrates, 3) photovoltaics, and 4) fusion.

“Also, on hydrogen: moving toward an “H2 economy” is fine but we better keep in mind that no amount of technology will ever change one basic fact: H2 is not a free molecule on the Earth’s surface.”

Yes, that’s absolutely true. But H2 can be easily made from water. And it can be used in fuel cells at very high conversion efficiencies, and producing only water.

“Sure, we can radically ramp up nuclear in order to make H2 from H2O, but we’re always going to be paying a pretty high price for it.”

You make two mistakes here. First, you use “nuclear” synonymously with “fission.” That completely ignores fusion, which is the much more logical long-range nuclear option. You also ignore photovoltaics. The world could easily get ALL its energy from photovoltaics. The only real barrier is cost (including the cost to store the electricity during the night…which is where the H2 comes into play).

As I’ve mentioned already to Roger Pielke Jr., if you folks at Prometheus really want to do a truly world-changing policy paper, y’all should calculate just what technological rewards would be appropriate for bringing fusion (most likely, non-tokamak fusion) to commercial fruition. The rewards which the U.S. government could offer to bring fusion to commercial fruition could be incredibly large (over $10 billion) as still EASILY be justified in terms of a ridiculously high return on investment.

MB – the world is decarbonizing? I assume you mean ‘carbon used per output of work’ or something like that. Well sure, the machinations of technological advance is working the ratio to our favor, but — as Jevons’ Paradox shows so well — that very decarbonization has led to a severe ramp up in total carbon burned. And as the output/carbon used ratio gets better and better, what happens? Suddenly carbon-burning technologies are well within the reach of “developing countries” with very large populations, which means even more carbon used in sum.

Also, on hydrogen: moving toward an “H2 economy” is fine but we better keep in mind that no amount of technology will ever change one basic fact: H2 is not a free molecule on the Earth’s surface. Which means we must expend energy to extract it before we can even get the energy back by burning it. Unlike oil and nuclear, which are gifts of solar energy/photosynthsis, geology, time and astrophysics, H2 is not a ready made fuel and it will always, no matter what we learn, be a net energy sink. Sure, we can radically ramp up nuclear in order to make H2 from H2O, but we’re always going to be paying a pretty high price for it.

This assertion is not supported by history. The world has been “decarbonizing” for centuries…it’s ridiculous to expect that would *not* continue.

The world by the end of the 21st century will almost certainly be a “hydrogen economy”…regardless of what governments do.

http://phe.rockefeller.edu/future_business/

The market unaided will not address the issue of ACC because that’s not the market’s role. The market is not a sentient being with your best interests at heart, it’s just a market. For buying and selling stuff. What matters is whether you accept scientific evidence, how you weight the alternative policy options that your assessment of that evidence suggest to you, and how much you value complex things like the environmental future of the most beautiful and fruitful planet in the history of the universe …