The energy challenge

I just went to the first of a new lecture series at Caltech, NRG 0.1, during which various experts are going to be discussing various aspects of the energy problem (for which read “challenge”) that the world is facing.

This week was Steve Koonin, former Caltech provost and physics professor, and currently chief scientist for BP. I thought it was an excellent talk, covering a lot of the different aspects to the energy question, and some important principles that need to be kept in mind when looking for solutions in the near and medium term. I particularly enjoyed (and, yes, this probably says something about me too) how the talk assembled a large collection of numbers into a few key “back-of-the-envelope” facts, and then analysed the various options in terms of these constraints. While I’m not going to summarise the whole talk (which will hopefully be available here soon), here are some of the things which stood out:

2050 / twice pre-industrial
By BP’s Business as Usual (BAU) analysis, sometime before 2050 CO2 will hit twice pre-industrial atmospheric levels. This is a tipping point in many models, and so serves as a useful “safe” upper limit. Anything we do has to have a big effect well before 2050.

Running out of oil vs. global warming
A few years ago I was more concerned about the former; now I think I’m more concerned about the latter. The global economy is handling the high oil prices very well, so non-conventional oil, like oil sands in Canada, really start to look accessible. Oil prices may stay high, and national concerns about oil supply security may discourage oil use, but I think it’s here for a few more decades. My take home message: global warming will be solved, or not, before oil runs out.

CO2 has to drop hugely
CO2 has a lifetime of many centuries once it’s in the atmosphere. Thus to reach CO2 stability at twice pre-industrial levels by 2050, we actually need to cut emissions by about half from today’s level. (A useful figure: due to CO2 longevity, a drop of 10% in CO2 emissions growth delays by about 7 years the crossing of any given atmospheric CO2 concentration). But by business as usual estimates, economic growth, even including historically extrapolated improvements in efficiency, will have raised emissions by a factor of 4. So we have to improve somehow by a factor of 8. As Koonin points out, efficiency gains are generally overwhelmed by increased consumption.

CO2 drops have to start now
As CO2 stays in the atmosphere, delaying change by a few years’ delay makes the required drops much larger in future. Furthermore, the main drivers of emissions (power plants, houses, cars, etc.) all have lifetimes of decades — so the power plants being built now will still be emitting by 2050. Basically, if nothing dramatic changes in the next 5 to 10 years, stability by 2050 becomes nearly impossible.

Many “solutions” just don’t scale
There’s huge enthusiasm for corn-based biofuels in the US at the moment. Koonin’s figures were that about 20% of the corn crop is now going to fuels, contributing about 2% of the US’s transport fuel needs. This doesn’t scale to solve the problem. Another example: solar. It’s a lot more expensive, and so will never be accepted commercially. But even if it was, we need to cover (if I recall the figure) a million rooftops with solar panels every year, starting right now, to reach stability by 2050. I’m not sure if that was globally or just the US.

$30/ton CO2
Currently, emitting CO2 is free in most places (Europe is a partial exception). That makes coal the cheapest power source. Most emissions reduction schemes assign a cost, one way or another, to CO2. Koonin had an interesting comparison graph: below about $20/ton CO2, coal remains cheapest. Above about $40/ton, there are no further major changes to the ordering of energy sources. So the magic number of balancing economic cost and yet still changing behaviour is around $30/ton. This would add only about 15% to the cost of petrol in the US or SA, and a little less in Europe, say. So the biggest changes will be in fixed electrical generation plants (which anyway are the biggest emitters).

The plan
Koonin’s take on matters, and I think I agree, is that given the size and cost of the changes needed, as well as their urgency, market forces have to be used to make changes. That is, we can’t pick an “ideal solution” and decree that that is what will be done — the political will isn’t there over the time scale required. Rather, the correct policy incentives need to be put in place right now — like a fixed, predictable cost for CO2 (which, interestingly, argues against a cap-and-trade approach), for the next 50 years. Without such definiteness, it becomes really hard for power companies to spend, say, an extra billion dollars now on a power plant that does CO2 sequestration.

Koonin’s roadmap would seem to be: policy incentives right now, leading to CO2 sequestering power plants still running predominantly off fossil fuels; a growing but still far from dominant contribution from sustainable power sources; and revolutionary improvements in next generation biofuels (using plant material that we do not, in fact, want to eat). He justifies hope in a biofuel revolution by pointing out that biotechnology is a very young and rapidly developing field — unlike, say, fusion. He also thinks there’s a chance for a solar revolution, but not with current technology.

As I overheard a participant say on the way out, though, “He could have given a much more pessimistic talk with the exact same slides”. We do have to make immediate, dramatic changes to an area of human endeavour that has vast pre-existing infrastructure, very long time-lines and huge costs. This for a problem that is hard to easily demonstrate now, and exists over a time scale far longer than political cycles. I think there’s a fair chance that, come 2050, we’ll have to be involved in some sort of huge active geoengineering (ie. a modification designed to “cancel out” our CO2 emissions), in order to stabilise the climate.

What are dimensions?

Since I’ve hardly been filling this blog with posts recently, I thought I might post an email I wrote recently, in reply to a question I received about the nature of dimensions. Mine is by no means a complete answer, but maybe it’s interesting. Follow-up questions welcome!

The question:

I have been reading a lot of books and web sites on string theory. It all seems very interesting, all these extra dimension and so fourth. I was just curious, it is supposed that these extra dimensions could be real, I have yet to read how the first three dimensions that we take for granted in this universe are real physical things. I know that the term dimension is used in plotting locations and trajectories of objects in space on paper, but are they real physical things that exist in the real universe?
I would really appreciate your help in this.

That’s a tricky question. To start with the three dimensions of space (and one of time) that we’re well aware of: they’re real in that they are what makes space, well, space. The idea of “space” is that it provides somewhere that things can be — without dimensions, there’d be no way to talk about where something is, how far apart things are, and so forth. Motion is merely the movement of things within the space.

Now that’s all there was to space, before relativity. Einstein’s General Relativity shows that space itself is a “dynamical” object, which means essentially that it is something that can change. Basically, matter and space interact — space is how you define where something is, but the presence of something (matter and/or energy) in turns affects the lengths of nearby pieces of space. So light travelling near a star is “bent” by the gravity of the star, as a result of the mass of the star affecting the definition of coordinates and motion nearby. So in this respect dimensions and space become a physical entity on which matter has an effect.

The additional dimensions predicted by string theory are no different to the three (plus time) that we’re used to, at least conceptually. When specifying the position of something, we just need to specify locations in each of nine directions, as well as a time. However, the fact that in our daily lives we only experience three of those spacial dimensions means that the other six are somehow irrelevant on large length scales. This might because they’re “rolled up” really small, by which I mean that the possible range of positions in that dimension is very small, and so everything is so close to everything else in that direction that we can’t even tell that there is another dimension. Alternatively, the particles from which we’re made might be in some sense “trapped” on the surface of a three-dimension object in the nine spacial dimensions.

However, in a very real sense we still don’t actually know what spacetime really is. Quantum gravity considerations strongly suggest that space is not continuous on the smallest scales — there should exist a smallest possible length, the Planck length. Any length smaller than this makes no sense. Furthermore, gravity and the effect of mass on spacetime arise in the string theory in an exactly analogous way to that in which particles arise — as specific vibrational modes of strings. So this seems to complete our growing re-interpretation of spacetime from being merely a fixed measurement apparatus on which physics happens, to being itself a part of physics. This makes physics very difficult, however, as most of our current techniques rely on the existence of concepts like detectors at spacial infinity, or being able to define a universal starting time for an interaction. So in my opinion certainly one of the interesting areas that string theory will be exploring in coming years is “emergent geometry”, where concepts that look at large scales like spacetime will turn out to arise from quite different interactions in some theory that resembles string theory in certain regimes.

Ethical democracy: An exercise for the reader

With a title like the above, there are so many things this post could be about — the last few days and weeks have been excellent for providing examples of less-than-ethical democracy. But this post is in fact about none of them — it’s about a tricky personal conundrum I faced today, in exercising ethical democracy.

The thing is, I’m not a US voter, or citizen. But I am a US taxpayer and legal resident at the moment. Tomorrow the US Congress will be voting on a bill (of which more later) on an issue very dear to my heart — because it represents probably the largest ongoing damage that the US does, every day, to the poorest of the poor in the developing world and especially Africa (of which I am a citizen). So the question for the reader is: should I phone my representative in Congress and ask them to vote the way I’d like on the bill?

The bill in question is the huge farm bill, and more especially the Fairness Amendment component thereof. US (and to be fair, European) farm subsidies are a mess: they cost the taxpayer huge sums, benefit predominantly the largest agribusiness concerns instead of small farmers, offer only marginal assistance to hungry people within the US and EU, and make it impossible for developing world (especially African) farmers to compete on the global market. For instance, farming cotton in Texas costs about three times the raw price it does in Mali, on the southern edge of the Sahara. But after subsidies Malian farmers can’t compete — and so huge areas of Africa aren’t even being farmed. Cotton is Mali’s main commercial export, despite this huge disadvantage — so one can only imagine the huge difference even a small tweak to the subsidies would make to the 10 million inhabitants of this desperately poor country. And as in cotton, so too elsewhere — US and EU farm subsidies are together larger than the total GDP of sub-Saharan Africa. But enough rant — contact me if you’d like more!

Anyway, the Fairness Amendment is a step in the right direction. The vote is tomorrow. In the end I went ahead and phoned my Congressional rep — using this really convenient and easy service.

Now the more suspicious amongst you might think that what this post is really about is getting those of you who can phone US representatives without suffering any complicated ethical choices, to indeed go ahead and phone. In fact, you might even be right. But I am also interested in what people think about whether it’s ethical for me to make such a phone call.

And yes, it’s been a while since my last blog post. I have a few stacked up awaiting typing, but this one came first thanks to the obvious deadline. Thanks for your patience!