Reducing Greenhouse Gas Emissions

Leaving aside the obstinate few, the world is now coming to realize that our activities are irreversibly changing the climate through sending so-called greenhouse gases into the atmosphere. Finally a number of politicians (but not President Trump) have decided they have to do something about it. Economists argue the answer lies in taxes on emissions, but that will presumably only work if there are alternative sources of energy that do not cause an increase in emissions. The question is, what can be done?

The first thing to note is the climate is significantly out of equilibrium, that is to say, the effects have yet to catch up with the cause. The reason is, while there is a serious net power input to the oceans, much of that heat is being dissipated by melting polar ice. Once that melting process runs its course, there will be serious temperature rises, and before that, serious sea level rises. My point is, the net power input will continue long after we stop emitting greenhouse gases altogether, and as yet we are not seeing the real effects. So, what can we do about the gases already there? The simplest answer to that is to grow lots and lots of forests. There is a lot of land on the planet that has been deforested, and merely replacing that will pull CO₂ out of the air. The problem then is, how do we encourage large-scale tree planting when economics seems to have led to forests being simply cut and burned? In principle, forest owners could get credits through an emissions trading scheme, but eventually we want to encourage this without letting emitters off the hook.

Now, suppose we want to reduce our current rate of emissions to effectively zero, what are the difficulties? There are five major sources that will be difficult to deal with. The first is heating. Up to a point, this can be supplied by electricity, including the use of heat pumps, but that would require a massive increase in electrical supply, and an early objective should be to close down coal-fired electricity generators. We can increase solar and wind generators, but note that there will be a large increase in emissions to make the construction materials, and there is a question as to how much they can really produce. Of course, every bit helps.

The second involves basic industrial materials, which includes metal smelting, cement manufacture, and some other processes where high temperatures and chemical reduction are required. In principle, charcoal could replace coal, if we grew enough forests, but this is difficult to really replace coal.

The third includes the gases in a number of appliances or from manufacturing processes. The freons in refrigerators, and some gases used in industrial processes are serious contributors. There may not be so much of them as there is of carbon dioxide, but some are over ten thousand times more powerful than carbon dioxide, and there is no easy way for the atmosphere to get rid of them. Worse, in some cases there are no simple alternatives.

The fourth is agriculture. Dairy farming is notorious for emitting methane, a gas about thirty-five times stronger than carbon dioxide, although fortunately its lifetime is not long, and nitrous oxide from the effluent. Being vegetarian does not help. Rice paddies are strong emitters, as is the use of nitrogen fertilizer, thus ammonium nitrate decomposes to nitrous oxide. Nitrous oxide is also more powerful and longer lived than carbon dioxide.

The fifth is, of course, transport. In some ways transport is the easiest to deal with, but there are severe difficulties. The obvious way is to use electric power, and this is obviously great for electrified railways but it is less satisfactory without direct contact with a mains power supply. Battery powered cars will work well for personal transport around cities, but the range is more questionable. Apparently rapid charge batteries are being developed, where a recharge will take a bit over a quarter hour, although there is a further issue relating to the number of charging points. If you look at many main highways and count the number of vehicles, how would you supply sufficient charging outlets? The recharge in fifteen minutes is no advantage if you have to wait a couple of hours to get at a power point. Other potential problems include battery lifetime. As a general rule, the faster you recharge, the fewer recharges the battery will take. (No such batteries last indefinitely; every recharge takes something from them, irreversibly.) But the biggest problem is power density. If you look at the heavy machinery used in major civil engineering projects, or even combine harvesters in agriculture, you will see that diesel has a great advantage. Similarly with aircraft. You may be able to fly around the world in a battery/solar-powered craft, but that is just a stunt, as the aircraft will never be much better than a glider.

One answer to the power density problem is biofuels. There are a number of issues relating to them, some of which I shall put in a future post. I have worked in this field for much of my career, and I have summarized my thoughts in an ebook “Biofuels”, which over the month of July will be available at $1 at Smashwords. The overall message relating to emissions, though, is there is no magic bullet. It really is a case of “every bit helps”.

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The Grenfell Fire, and the Logic of Plastics in Cladding

For me, the most depressing recent news was the London fire, in which a high-rise of flats (apartments for Americans) somehow caught fire, and once it did, it spread like crazy. There is a lot of blame to share around for the death toll. Apparently people were told to stay in their flats, but that advice was given by firemen who were unaware that the building had no useful fire doors, or the other usual means of containing and retarding fires. After all, if the building is concrete, and there is no easy way to spread the fire, it should be able to be kept local. So what went wrong? We don’t know about why the interior of the building seemed to burn very nicely, but it seemed that the outside burned furiously. The outside had an aluminium cladding, apparently to make it look more attractive. The aluminium tiles were backed by polyethylene, which is essentially a solid hydrocarbon of structure similar to diesel, but a much larger molecular weight. That burns very well, and if you saw video of it, you would see great globs of fire falling off the building.

We don’t know exactly why the polyethylene was there. Some say heat insulation, others say to give the cladding rigidity. Much has also been made of the fact that for about $3 a tile more, the backing could have been fire resistant. I am not sure what that backing is as the maker’s website does not say, but would guess it is some sort of polyamide or polyurethane with non-flammable filler. These certainly do not catch fire as easily, but there is another catch with some of them: in a fire they do burn, and while not as well, they tend to give off some rather poisonous gases. There is another catch. According to the manufacturer, the fire resistant tiles passed ASTM E 84 tests, which are the standard tests for surface burning characteristics, but so did the polyethylene backed tiles. That sort of lab test does not represent a real fire.

This brought back memories of my past, when I got involved with two structural foams that could be suitable for building cladding. One was a glass foam, originally intended to be made from waste glass. This would make quite a good wall cladding without the aluminium, except possibly on the bottom floor because it does not have very good impact resistance. Thin glass shatters on impact, but it does not burn or corrode. You can also have a wide range of colours. The other is a plastic foam, for which you do not even need fillers to make it fire resistant.

The story of my involvement with that goes back to the late 1970s. In the late 1960s, New Zealand discovered a large offshore natural gas field, and the government took it upon itself to enter a “take or pay” agreement so the field would be developed. It was not clear what their idea was, but presumably electricity generation was one of them. However, when the first energy crisis struck, about 1972 from memory, there was a sort of panic, and after a lot of deliberation they decided to construct a synthetic fuels plant at Motunui, which was to use a process developed by Mobil. I was on a committee to advise on the science, and I advised this was a bad idea because they could not build it for anything like the costs presented to them. As it turned out, my projected cost was out by $200 million, but no site had been chosen, and my estimate was “plus site development”. (In the end, the site development would have been about $130 million, so I was rather pleased with myself.) However, at the committee, I was about 4.5 times greater than the figure they were comfortable with (and note the government was going to pay) so I was never asked to be on such committees again. However, when that process was chosen, I knew that there was one byproduct they would not know what to do with: 1,2,4,5-tetramethylbenzene. The reason: it is a solid, which is not good in petrol for cars. The good news from my point of view was that it could be oxidized to pyromellitic dianhydride, which would be a precursor to stepladder and even ladder polymers, and in particular to polyimide plastics. The bad news was that the top public servants did not want their synfuels project upstaged, and the politicians were unenthused, probably because they were totally out of their depth.

So to get rid of the road blocks, I needed a stunt. As it happened, the fire hazard with plastic foams was to be the subject of a half-hour nationwide TV program, and I was invited to comment as a scientist. I agreed, provided I could have a few minutes for a demonstration of fire resistant foams. That was agreed, so I made myself some polyimide foam. This was rigid, and not much use for furniture, but you can’t really do much development work with one day’s notice. So I turned up, and at the end of the program, which had the dangers of fires, and of the poisonous gases drilled into everyone, I had the cameras turned on me. I put a bit of home-made foam in the palm of my hand and directed a gas torch at it. It glowed a nice yellow-hot under the flames, and I just sat there. Eventually they got bored of watching this, and they turned off the torch, then made the comment, “It still stinks, though.” So, with a bit of acting here, I held the plastic up to my face and sniffed deeply, and made no expression. Since there was no fire, while the plastic was ablating slowly, once the torch was taken away there was no more reaction. Unfortunately, my wife forgot to record this so I can’t actually prove it.

The whole point of this, of course, is it is possible to make very fire resistant foams. Without the type of chemical plant I was proposing, such foams would be expensive, but the question then is, is preventing x number of deaths worth spending a few extra dollars (or in this case, pounds)? In my opinion, there is no real excuse. Yes, the foam I made was rigid, but as building insulation, so what? While science can provide answers to many problems, there is not much point in it if nobody in power takes any notice.

UK Election Fallout and Qatar: what would you do if in charge?

Suppose like me you are an author of fiction. Given the following situations, put yourself in someone’s shoes and ask yourself, what next?

The first event was the rather unfortunate end result of the UK election. What was delivered was what I consider to be the worst possible outcome. The problem is, voters are sucked in by “jam today”, or “I am annoyed about something.” So, what now? First, some background. The national debt of Britain now stands at £ 1.73 trillion, and the interest payment on this debt is about 6% of revenue. That might seem to be reasonably sustainable, but there is the overall issue of Brexit looming. The UK has apparently had a recent surge in GDP, despite the threat of Brexit, but it is not clear that will last, and interest rates will probably grow from their record low. Suppose they double, which is easy from such lows. 6% suddenly turns to 12%, and that is ugly. (The existing loans will stay at their agreed rate, but can you pay them back when they mature? Otherwise you have to borrow at the new rate.) It appears that Jeremy Corbyn was promising a lot of spending, together with an unspecified increase in taxes. My guess is a lot of the youth vote that went to Corbyn thought the rich would pay. The usual problem with that assessment is that while the rich can be made to pay significantly higher taxes, to get the amounts needed to make a significant difference in revenue tax rises have to go a lot deeper. There are just not enough rich to soak. On the other hand, people may well argue they needed more money to go to health, education, or whatever. The question then is, can you pay for what you want?

May was apparently promising austerity. That is hardly attractive, but it was also put forward in a rather clumsy way. Cutting out school lunches is not only hardly a vote winner, but it is also never going to make a huge difference. Putting that up front is a strange way to win an election. It seems that the Tories were so convinced they were going to win that they decided to put up some policies that they knew would be unpopular, so they could say later, “You voted for them.” The two who are believed to have largely written the manifesto have resigned (really, pushed by angry senior Tories) but the question remains, why were they left to write it? Why did the senior Cabinet Ministers not know what was in it, or if they knew, why did they not do something about it? There’s plenty of blame to go around here, folks, nevertheless there are two hard facts: if Britain and the EU cannot manage Brexit properly, there will be severe economic problems, and economic problems seem to be like a very active virus that goes everywhere very quickly. The second is, if debt gets out of hand, the country spends so much on interest repayments that it ends up in the position Greece is now in. Anyone want that?

So, put yourself in some position: what would you do? My opinion is the Tories should realize that Corbyn has no chance currently of forming a government (because he needs every non-Tory vote) and get on doing something that has at least some public appeal. May either has to go, or learn oratory and get some empathy for the others.

The other event is the Arab attempt at isolating Qatar, on the grounds it is financing terrorism. Actually, the Saudis are almost certainly the biggest such supporters. The real reason appears to be either Qatar is friendly with Iran, or alternatively Qatar is the home of al Jazeera, a TV network that tries by and large to report the facts, warts and all. The US position on this is obscure. President Trump has lashed out against Qatar, without any particular evidence, although Qatar is known to have given refuge a number of Egypt’s Muslim Brotherhood. The US is also bombing Assad’s troops in Syria to prevent them getting at fleeing ISIS fighters; it seems that terrorism is being actively supported by the US, which make no strategic sense. At first, it looks as if Qatar could be quickly invaded from Saudi Arabia, but whoever does that would have to be very careful because Qatar houses the biggest local US base in the region, and has 11,000 military personnel there. To add to the complications, Turkey has promised to send troops. Fighting Turkey should mean fighting NATO, although with President Trump nothing automatically follows.

So, imagine you are the leader of Qatar, what would you do? Return the Muslim Brotherhood members to Egypt where they would probably be tortured and/or executed? Promise to stop funding terrorists? (If you really are not, this is easy to keep, but maybe not so easy to convince others that you are keeping it.) Remember, whatever you decide to do, you have to be prepared for whatever consequences follow. Not easy working out what leaders should do, is it? Writing fiction is, of course, easier, because you control what happens next. But if you want that fiction to have some relation with reality, what happens next has to be plausible, so here is your chance to get some practice.

Star and Planetary Formation: Where and When?

Two posts ago, as a result of questions, I promised to write a post outlining the concept of planetary accretion, based on the current evidence. Before starting that, I should explain something about the terms used. When I say something is observed, I do not mean necessarily with direct eyesight. The large telescopes record the light signals electronically, similarly to how a digital camera works. An observation in physics means that a signal is received that can be interpreted in one only certain way, assuming the laws of physics hold. Thus in the famous two-slit experiment, if you fire one electron through the slits, you get one point impact, which is of too low an energy for the human eye to see. Photomultipliers, however, can record this as a pixel. We have to assume that the “observer” uses laws of physics competently.

The accretion of a star almost certainly starts with the collapse of a cloud of gas. What starts that is unknown, but it is probably some sort of shock wave, such as a cloud of debris from a nearby supernova. Another cause appears to be the collision of galaxies, since we can see the remains of such collisions that are accompanied by a large number of new stars forming. The gas then collapses and forms an accretion disk, and these have been observed many times. The gas has a centre of mass, and this acts as the centre of a gravitational field, and as such, the gas tries to circulate at an orbital velocity, which is where the rate of falling into the star is countered by the material moving sideways, at a rate that takes it away from the star so that the distance from the centre remains the same. If they do this, angular momentum is also conserved, which is a fundamental requirement of physics. (Conservation of angular momentum is why the ice skater spins slowly with arms outstretched; when she tucks her arms in, she spins faster.

The closer to the centre, the strnger gravity requires faster orbital velocity. Thus a stream of gas is moving faster than the stream just further from the centre, and slower than the stream just closer. That leads to turbulence and friction. Friction slows the gas, meaning it starts to fall starwards, while the friction converts kinetic energy to heat. Thus gas drifts towards the centre, getting hotter and hotter, where it forms a star. This has been observed many times, and the rate of stellar accretion is such that a star takes about a million years to form. When it has finished growing, there remains a dust-filled gas cloud of much lower gas density around it that is circulating in roughly orbital velocities. Gas still falls into the star, but the rate of gas falling into the star is at least a thousand times less than during primary stellar accretion. This stage lasts between 1 to 30 million years, at which point the star sends out extreme solar winds, which blow the gas and dust away.

However, the new star cannot spin fast enough to conserve angular momentum. The usual explanation is that gas is thrown out from near the centre, and there is evidence in favour of this in that comets appear to have small grains of silicates that could only be formed in very hot regions. The stellar outburst noted above will also take away some of the star’s angular momentum. However, in our system, the bulk of the angular momentum actually resides in the planets, while the bulk of the mass is in the star. It would seem that somehow, some angular momentum must have been transferred from the gas to the planets.

Planets are usually considered to form by what is called oligarchic growth, which occurs after primary stellar accretion. This involves the dust aggregating into lumps that stick together by some undisclosed mechanism, to make first, stone-sized objects, then these collide to form larger masses, until eventually you get planetesimals (asteroid-sized objects) that are spread throughout the solar system. These then collide to form larger bodies, and so on, at each stage collisions getting bigger until eventually Mars-sized bodies collide to form planets. If the planet gets big enough, it then starts accreting gas from the disk, and provided the heat can be taken away, if left long enough you get a gas giant.

In my opinion, there are a number of things wrong with this. The first is, the angular momentum of the planets should correspond roughly to the angular momentum of the dust, which had velocity of the gas around it, but there is at least a hundred thousand times more gas than dust, so why did the planets end up with so much more angular momentum than the star? Then there is timing. Calculations indicate that to get the core of Jupiter, it would take something approaching 10 million years, and that assumes a fairly generous amount of solids, bearing in mind the solid to gas ratio. At that point, it probably accretes gas very quickly. Get twice as far away from the star, and collisions are much slower. Now obviously this depends on how many planetesimals there are, but on any reasonable estimate, something like Neptune should not have formed. Within current theory, this is answered by having Neptune and Uranus being formed somewhere near Saturn, and then moved out. To do that, while conserving angular momentum, they had to throw similar masses back towards the star. I suppose it is possible, but where are the signs of the residues? Further, if every planet is made from the same material, the same sort of planet should have the same composition, but they don’t. The Neptune is about the same size as Uranus, but it is about 70% denser. Of the rocky planets, Earth alone has massive granitic/feldsic continents.

Stronger evidence comes from the star called LkCa 15 that apparently has a gas giant forming that is already about five times bigger than Jupiter and about three times further away. The star is only 3 million years old. There is no time for that to have formed by this current theory, particularly since any solid body forming during the primary stellar accretion is supposed to be swept into the star very quickly.

Is there any way around this? In my opinion, yes. I shall put up my answer in a later post, although for those who cannot wait, it is there in my ebook, “Planetary Formation and Biogenesis”.