Science and Sanctions

This may seem an odd title in that most people consider science far away from describing human activities. I am not suggesting the scientific method should govern all of human activities, but I think that a little more attention to its methods would help humanity (and I try to show a little of this in my novels, although I am unsure that most would notice). The first important point, of course, is to clarify what the scientific method is. Contrary to what you may see on TV programs, etc, it is not some super geek sitting down solving impossible mathematical equations. Basically, the scientific method is you form propositions, perhaps manipulate them, then check with reality whether they might be correct. The most important feature here is, check the evidence.

What initiated this post was news that the US House of Representatives has passed a bill that will impose new sanctions on Russia, including (according to reports here) the forbidding of any help with Russia’s oil and gas industry, and President Trump has signed it into law. So, what are the premises behind this?

The first one is that foreign countries will oblige and help carry them out.

The second, presumably, is that Russia will now fall into line and do whatever the sanctions are intended to make it do.

The third is, if Russia cannot export more oil or gas, their prices will rise.

The fourth is, removing Russian hydrocarbons from the international market will lead to further markets for US hydrocarbons. Note the US now has the capacity to be a major exporter, thanks to fracking.

The first two depend on each other, and obviously, seeking evidence of the future is not practical, nevertheless we can look at the history of sanctions. Are there any examples of countries “bending the knee” in response to sanctions when they probably would not have done it anyway? I cannot think of any. Obviously, sanctions are less likely to effective if foreign countries refuse to cooperate, which is why the two are linked. The two most recent examples of sanctions are Iran and North Korea. Both have been imposed for sufficient time, and the question is, how effective are they?

In the case of Iran, one objective is claimed to have been met in that Iran argues it no longer has the capacity to make nuclear weapons, however it also claimed that was never its intention. Everyone seems to delight in arguing whether either of those statements is true, but in my opinion nuclear weapons are a poor strategic objective for Iran. I also believe they are a poor option for North Korea, but seemingly someone has to show Kim that is so. For either of them, what would it gain? Iran has opted (if truthful) to avoid nuclear weapons, but then again, what has it gained from doing so? The sanctions America imposed are still largely there. As for the effectiveness of sanctions, it appears that Iran is doing reasonably well, and a number of countries are buying its oil, including China. So I conclude that sanctions are not particularly effective there.

North Korea does not seem in any immediate hurry to “bend the knee” to the US and while it has suffered the harshest sanctions, apparently over the last few years its exports have increased by at least 40%, mainly to China. President Trump has accused China of not helping, and he is correct, but being correct does not get anyone very far. The obvious question is, why is North Korea chasing after better weapons? The answer is obvious: it is at war with the US and South Korea. The Korean War never ended formally. The sides agreed to a ceasefire, but no permanent treaty was signed, so one of the actions that America could have taken in the last sixty years or so would have been to negotiate a formal peace treaty. You may well say, the US would never launch a preemptive strike against North Korea. You may well be right, but are you that sure? From North Korea’s point of view, the US has launched cruise missile attacks frequently against places it does not like, it has significant military bases in Syria, it invaded Iraq, and so on. You might argue that the US was justified because these countries were not behaving, and you may well be right, but from North Korea’s point of view, it is at war with the US already, so it has decided to do what it can to defend itself. One approach to end this ridiculous position would be to at least offer a treaty.

The third and fourth premises are probably ones the US Congress does not advertise, because they are full of self-interest. Apparently there is enough liquefied natural gas able to be produced to substitute for Russian gas in Europe. So, why don’t they sell it? Competition is a good thing, right? The simplest answer is price and cost. Europe would have to build massive lng handling facilities, and pay a lot more for their gas than for Russian gas. And it is here that these sanctions may run into trouble. The Germans will lose heavily from the loss of Russian gas, in part because their industries are involved in expanding the Russian fields and pipelines, and of course, they would have to pay more for gas, and some equipment would need changing for the different nature of the gas.

So, if we return to the evidence, I think we can conclude that these latest attempts at sanctions are more based on self-interest than anything else. There is no evidence they will achieve anything as far as pushing Russia around goes. It is true, if imposed, they would hurt Russia significantly, but they would also hurt Europe, so will Europe cooperate?

Liquid Fuels from Algae

In the previous post, I discussed biofuels in general. Now I shall get more specific, with one particular source that I have worked on. That is attempting to make liquid fuels from macro and microalgae. I was recently sent the following link:

https://www.fool.com/investing/2017/06/25/exxonmobil-to-climate-change-activists-chew-on-thi.aspx

In this, it was reported that ExxonMobil partnering Synthetic Genomics Inc. have a $600 million collaboration to develop biofuels from microalgae. I think this was sent to make me green with envy, because I was steering the research efforts of a company in New Zealand trying to do the same, except that they had only about $4 million. I rather fancy we had found the way to go with this, albeit with a lot more work to do, but the company foundered when it had to refinance. It could have done this in June 2008, but it put it off until 2009. I think it was in August that Lehmans did a nosedive, and the financial genii of Wall Street managed to find the optimal way to dislocate the world economies without themselves going to jail or, for that matter, becoming poor; it was the lesser souls that paid the price.

The background: microalgae are unique among plants in that they devote most of their photochemical energy into either making protein and lipids, which in more common language are oily fats. If for some reason, such as a shortage of nitrogen, they will swell up and just make lipids, and about 75 – 80% of their mass are comprised of these, and when nitrogen starved, they can reach about 70% lipids before they die of starvation. When nitrogen is plentiful, they try to reproduce as fast as they can, and that is rapid. Algae are the fastest growing plants on the planet. One problem with microalgae: they are very small, and hence difficult to harvest.

So what is ExxonMobil doing? According to this article they have trawled the world looking for samples of microalgae that give high yields of oil. They have tried gene-editing techniques to grow a strain that will double oil production without affecting growth rate, and they grow these in special tubes. To be relevant, they need a lot of tubes. According to the article, if they try open tanks, they need an area about the size of Colorado to supply America’s oil demand, and a corresponding lot of water. So, what is wrong here? In my opinion, just about everything.

First, you want to increase the oil yield? Take the microalgae from the rapidly growing stage and grow them in nitrogen-starved conditions. No need for special genetics. Second, if you are going to grow your microalgae in open tanks (to let in the necessary carbon dioxide and reduce containment costs) you also let in airborne algae. Eventually, they will take over because evolution has made them more competitive than your engineered strain. Third, no need to consider producing all of America’s liquid fuels all at once; electricity will take up some, and in any case, there is no single fix. We need what we can get. Fourth, if you want area, where is the greatest area with sufficient water? Anyone vote for the ocean? It is also possible that microalgae may not be the only option, because if you use the sea, you could try macroalgae, some of which such as Macrocystis pyrifera grow almost as fast, although they do not make significant levels of lipids.

We do not know how ExxonMobil intended to process their algae. What many people advocate is to extract out the lipids and convert them to biodiesel by reacting them with something like sodium methoxide. To stop horrible emulsions while extracting, the microalgae need to be dried, and that uses energy. My approach was to use simple high pressure processing in water, hence no need to dry the algae, from which both a high-octane petrol fraction and a high-cetane diesel fraction could be obtained. Conversion efficiencies are good, but there are many other byproducts, and some of the residue is very tarry.

After asking where the best supply of microalgae could be found, we came up with sewage treatment ponds. No capital requirement for building the ponds, and the microalgae are already there. In the nutrient rich water, they grow like mad, and take up the nutrients that would otherwise be considered pollutants like sponges. The lipid level by simple extraction is depressingly low, but the levels that are bound elsewhere in the algae are higher. There is then the question of costs. The big cost is in harvesting the microalgae, which is why macroalgae would be a better bet in the oceans.

The value of the high pressure processing (an accelerated treatment that mimics how nature made our crude oil in the first place) is now apparent: while the bulk of the material is not necessarily a fuel, the value of the “byproducts” of your fuel process vastly exceeds the value of the fuel. It is far easier to make money while still working on the smaller scale. (The chemical industry is very scale dependent. The cost of making something is such that if you construct a similar processing plant that doubles production, the unit cost of the larger plant is about 60% that of the smaller plant.)

So the approach I favour involves taking mainly algal biomass, including some microalgae from the ocean (and containing that might be a problem) and aiming initially to make most of your money from the chemical outputs. One of the ones I like a lot is a suite of compounds with low antibacterial activity, which should be good for feeding chickens and such, which in turn would remove the breeding ground for antibiotic resistant superbugs. There are plenty of opportunities, but unfortunately, a lot of effort and money required it make it work.

For more information on biofuels, my ebook, Biofuels An Overview is available at Smashwords through July for $0.99. Coupon code NY22C

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”.

Trump and Climate Change

In his first week in office, President Trump has overturned President Obama’s stopping of two pipelines and has indicated a strong preference for further oil drilling. He has also denied that climate change is real. For me, this raises two issues. The first is, will President Trump’s denial of climate change, and his refusal to take action, make much difference to climate change? In my opinion, not in the usual sense, where everybody is calling for restraint on carbon dioxide emissions. The problem is sufficiently big that this will make only a minor difference. The action is a bit like the Captain of the Titanic finding two passengers had brought life jackets so he confiscates them and throws them overboard. The required action was to steer away from a field of icebergs, and the belief the ship was unsinkable was just plain ignorant, and in my opinion, the denial that we have to do something reasonably dramatic about climate change falls into the same category. The second issue is how does science work, and why is it so difficult to get the problem across? I am afraid the answer to this goes back to the education system, which does not explain science at all well. The problem with science for most people is that nature cares not a jot for what you feel. The net result is that opinions and feelings are ultimately irrelevant. You can deny all you like, but that will not change the consequences.

Science tries to put numbers to things, and it tries to locate critical findings, which are when the numbers show that alternative propsitions are wrong. It may be that only one observation is critical. Thus Newtonian mechanics was effectively replaced by Einstein’s relativity because it alone allowed the calculation of the orbital characteristics of Mercury. (Some might say Eddington’s observation of light bending around the sun during an eclipse, but Newton predicted that too. Einstein correctly predicted the bending would be twice that of Newton, but I think Newton’s prediction could be patched given Maxwell’s electrodynamics. For Newton’s theory, Mercury’s orbit was impossible to patch.)

So what about climate change? The key here is to find something with the fewest complicating factors, and that was done when Lyman et al. (Nature 465: 334-337, 2010) measured the power flows across ocean surfaces, and found there was a net input of approximately 0.6 W/m². That is every square meter gets a net input of 0.6 Joules per second, averaged over the 24 hr period. Now this will obviously be approximate because they did not measure every square meter of ocean, but the significance is clear. The total input from the star is about 1300 W/m² at noon, so when you allow for night, the fact that it falls away significantly as we get reasonably away from noon, and there are cloudy days, you will see that the heat retained is a non-trivial fraction of the input.

Let us see what that means for the net input. Over a year it becomes a little under 19 MJ for our square meter, and over the oceans, I make it about 6.8 x 10²¹ J. There is plenty of room for error there (hopefully not my arithmetic) but that is not the point. The planet is a big place, and that is really a lot of energy: about a million million times 1.6 tonnes of TNT.

That has been going on every year this century, and here is the problem: that net heat input will continue, even if we totally stopped burning carbon tomorrow, and the effects would gradually decay as the carbon we have burnt gradually weathers away. It would take over 300 years to return to where we were at the end of the 19th century. That indicates the size of the physical problem. The fact that so many people can deny a problem exists, with no better evidence than, “I don’t believe it,” is our current curse. The next problem is that just slowing down the production of CO₂, and other greenhouse gases, is not going to solve it. This is a problem that has crept up on us because a planet is a rather large object. It has taken a long time for humanity’s efforts to make a significant increase to the world’s temperatures, but equally it will take a long time to stop the increase from continuing. Worse, one of the reasons the temperature increases have been modest is that a lot of this excess heat has gone into melting ice. Eight units of water at ten degrees centigrade will melt one unit of ice, and we end up with nine units of water at nought degrees Centigrade. The ice on the planet is a great restraint on temperature increases, but once the ice in contact with water has melted, temperatures may surge. If we want to retain our current environment and sea levels, we have some serious work to do, and denying the problem exists is a bad start.

Substitutes for fossil fuel

In my previous two posts I have discussed how we could assist climate change by reflecting light back to space, and some ways to take carbon dioxide from the atmosphere. However, there is another important option: stop burning fossil fuels, and to do that either we need replacement sources of energy, or we need to stop using energy. In practice, reducing energy usage and replacing the rest would seem optimal. We already have some options, such as solar power and wind power. New Zealand currently gets about 80% of its electricity from natural sources, the two main ones being hydro and geothermal, with wind power coming a more distant third. However, that won’t work for many countries. Nuclear power is one option, and would be a much better one if we could develop a thorium cycle, because thorium reactors do not go critical, you cannot make bombs from the wastes, and the nuclear waste is a lot safer to handle as the bulk of the radioactive wastes have very short half-lives. Thermonuclear power would be a simple answer, but there is a standard joke about that, which I might as well include:

A Princeton plasma physicist is at the beach when he discovers an ancient looking oil lantern sticking out of the sand. He rubs the sand off with a towel and a genie pops out. The genie offers to grant him one wish. The physicist retrieves a map of the world from his car, circles the Middle East and tells the genie, ‘I wish you to bring peace in this region’.

 After 10 long minutes of deliberation, the genie replies, ‘Gee, there are lots of problems there with Lebanon, Iraq, Israel, and all those other places. This is awfully embarrassing. I’ve never had to do this before, but I’m just going to have to ask you for another wish. This one is just too much for me’.

Taken aback, the physicist thinks a bit and asks, ‘I wish that the Princeton tokamak would achieve scientific fusion energy break-even.’

After another deliberation the genie asks, ‘Could I see that map again?’

So, although there is a lot of work to be done, the generation of electricity is manageable so let’s move on to transport. Electricity is great for trains and for vehicles that can draw power from a mains source, and for short-distance travel, but there is a severe problem for vehicles that store their electricity and have to do a lot of work between charging. Essentially, the current batteries or fuel cells are too heavy and voluminous for the amount of charge. There may be improvements, but most of the contenders have problems of either price or performance, or both. In my novel, Red Gold, set during a future colonization of Mars, I used thermonuclear power as the primary source of electricity, and for transport I used an aluminium chlorine fuel cell. That does not exist as yet, but I chose it because for power density aluminium is probably optimal for unit weight, and chlorine the optimal for the oxidizing agent because chlorine would be a liquid on Mars, and further under my refining scheme, there would be an excess of it. Chlorine has the added advantage that it reacts well with aluminium and the aluminium chloride will contribute to the electrolyte. As it happens, since then someone has demonstrated an Al/Cl battery that works very well, so it might even be plausible, but not on Earth. One basic problem with such batteries is an odd one: the ions that have to move in the electrolyte usually interact strongly with any oxygen atoms in the electrolyte, thus slowing down, and reducing the possible power output. That is another reason why I chose a chloride mechanism; it might be fiction but I try and make the speculative science behind it at least based on some correct physics and chemistry.

So, in the absence of very heavy duty batteries, liquid fuels are very desirable. As it happens, I have worked in the area of biofuels (and summarised my basic thoughts in an ebook Biofuels) and with a little basic arithmetic we find that to replace our current usage of oil, and assuming the most optimal technology, we would need to add another amount of productive land equal to our total arable farmland, and that is simply not going to happen. That does not mean that biofuels cannot contribute, but it does mean we need to reduce the load.

There is more than one way to do that. In one of my novels I came up with the answer of having everyone live closer to work. Where I live, during the rush hours there are streams of cars going in opposite directions. If they all lived closer to work, this would be unnecessary. Everyone says, use public transport, except that if you do, you see the trains are choked at that time of day. Such an option would require a lot of social engineering because the bosses want work done at centres where they think it should be done, while the workers cannot afford to live anywhere even vaguely nearby. That means social engineering is required, and people tend to object to that, and politicians will not impose it on the bosses.

As mentioned in my last post, a slightly better option is to grow algae. Some of these are the fastest growing plants on the planet, and of course as far as area is concerned, the oceans are unlimited, at least at present. Accordingly, it should be possible in theory to solve this energy problem. The problem is, though, with the technologies I have recommended here, they all require serious development. We know in principle how they all should work, except possibly nuclear fusion, but we do not know how to put the technology into a useful form. Meanwhile, with the low price of oil there is no incentive. Here, the answer is clear: a serious carbon tax is required on fossil fuels. I would like to see the resultant money being at least in part spent on developing potential technologies. Maybe this is my personal bias coming through – the promising algal technology I was working on collapsed when fund-raising was scheduled for the end of 2007, and thanks to Lehmans, that was not going to succeed. I am not alone. I am familiar with at least three other technologies of which I had no involvement but looked extremely promising, but they ran out of funding. As a society, can we afford the waste?

Reducing Greenhouse Gases: The Problem

In the previous post, I looked at the prospects for helping combat global warming by decreasing the solar input to the planet, mainly by reflecting light back to space. The basic problem is the size of the planet: to reduce solar input by 1% you have to totally reflect one per cent of the incoming radiation, which involved ideal reflectors of area somewhat greater than 4 x 10^11 square meters.

Superficially, option two, which is to increase heat output, is easier. All you have to do is to reduce the amount of greenhouse gases in the atmosphere. However, that is something of a problem because we are adding almost 9 billion tonne of carbon as greenhouse gases per year. So, to improve the current situation we have to devise a means of taking out more than 9 Gt of carbon, or over 33 billion tonne of carbon dioxide per annum. Worse, much of the carbon is in the form of methane, which is a much worse greenhouse gas, so a target of 50 billion tonne per annum of carbon dioxide is probably a minimal “hold the current state”. Again, the size of the problem is basically the problem.

Carbon dioxide is naturally removed from the atmosphere by weathering certain rocks. To oversimplify, silicates come in two main classes: granitic and basaltic. The granitic rocks have a much lower density than the basaltic, so they tend to float, and our continents are largely granitic, which, having a large fraction of their composition as aluminosilicates, and since aluminium does not form a stable carbonate, these rocks weather mainly to clays and not carbonates. Thus the main rocks of our continents are not going to help.

The basaltic rocks mainly comprise olivines or pyroxyenes, which are two families of iron/magnesium silicates, the former being nominally “salts” of silicic acid, and the latter salts of chains of polysilicic acid. These will weather to form silica and carbonates of their metals, but at varying rates. One of the proposals is to crush peridotite, one of the fastest to weather, into dust and incorporate it into soils. Powdering it increases surface area, thus increasing the rate of reaction because the reaction is limited to where the carbonic acid in water can get at something to react. It will still be slow, and the energy to crush the rock has to come from somewhere, and might be better used to substitute for the worst other means of producing energy. Another problem is that while peridotite is one of the most common rocks on the planet, that is because it is essentially an upper mantle rock, with only odd visits to the surface. Reacting the gaseous carbon dioxide with basalt is nature’s way of taking it from the atmosphere, but with all the basalt on the planetary surface, it will take centuries to remove the excess there now. This is not going work, although it would make sense to bury carbon dioxide if it were already isolated, but preferably into some basaltic zone.

A better way of removing carbon dioxide is to grow more forests, and in particular to permit the equatorial rain forests to regenerate. A further alternative is to grow massive amounts of algae, which would require ocean fertilization. Some marine algae are extremely rapid growing plants (with a microscope you can watch continuous cell division!). For macroalgae, in the 1970s the US Navy showed how such algae could be grown in open ocean water (as opposed to near coastlines) by growing on rafts and fertilizing with bottom water raised by wave power. The experiment succeeded until a rather unfortunate storm wrecked things, but that, to me is a design and engineering problem that could be solved. In short, the technology for growing plants is more or less available.

The algae could then be used to make synthetic fuels, and while that would merely cycle carbon dioxide, it is better than producing more. We could also bury carbon, as any such processing makes some carbon deposited as char. The growing of algae has one further possible advantage; it takes energy entering the oceans and stores it as chemical energy rather than as heat, and it also emits mercaptans, which should make more clouds after absorbing more ultraviolet light.

To be clear, neither of these will solve the problem, but growing plants will at least contribute to a solution.

So, why don’t we? Quite simply, economics. There are two main problems: the tragedy of the commons, and politicians. The first problem is that unless everyone contributes, the problem cannot be solved, but some, of course, will not mind climate change, or, alternatively, decide nothing will affect them, so why should they pay to fix it? Unfortunately, the expense is so great. This is part of why I favour the algal response. The growing of such algae will also support greater fish life, and hence improve the food supplies, and can be used to make liquid fuels, provided the right technology is used, and there is some chance it may increase cloud cover. By addressing three problems, two of which have money-making prospects as well, makes it more likely it would be successful. At first, of course, such algae could be grown near the current coastlines, and we know how to do that.

Politicians are a more intractable problem. An example: in New Zealand politicians were determined that an emissions trading scheme would be its response. Some New Zealanders began planting trees to get credits, but then Ukraine and Russia produced mountains of such paper credits, there price crashed, and while the current trees might be absorbing carbon dioxide, nobody is in a rush to plant more. If you have travelled the world, you will see vast area where forests have been removed and nothing done with the resultant land. Forests could be regrown, especially tropical ones. The problem then is, who pays for them? Why should Brazil, say, spend a lot of money to plant forests to benefit everyone else? It is politics and governance again.

Remedies for Climate Change: (1) Reflect!

In my post of a week ago, I raised the issue of climate change, and argued that because there is a net power input to the surface now, due to reduced cooling caused by the blanket effect of the so-called greenhouse gases, even if we stopped producing such gases right now, we would still have serious problems because the current rate of net ice melting would continue. Now, it is all very well to moan about it, but the question is, what should our response be? This is too complicated for one post, so this will start a small sequence, although not all will be consecutive.

The easiest response is to do nothing and keep going as we are. Eventually, the sea will rise by about 60 meters. That would drown London, Beijing, and a number of other cities, in fact almost every port city, and it would remove a huge amount of prime agricultural land. Suppose we do not wish that, what can we do? In logic, there are four main options: lower the heat input; raise the heat output; store input energy as chemical energy; increase snow precipitation on polar regions so that it makes up for the increased melting. The last option means we accept everything else, such as increased temperatures and worse storms, but we protect our land. Obviously, we should also reduce our output of so-called greenhouse gases, because while even stopping this output does not solve the problem, at least it stops making the problem increasingly more difficult.

You may argue that such options suffer from failure to be practical. Possibly, but unless we investigate, how do you know? Another argument sometimes put forward is we should not do anything because there could be unintended consequences. That too is true, but is drowning London and starving a great fraction of the population a desired consequence, because that is what happens if we do nothing?

Lowering the heat input is most easily achieved by reflecting more radiation to space i.e. increase the albedo of the planet or place reflectors in space. Increasing the albedo is probably most easily done by increasing cloud cover. One proposal I have seen to do that is to spray seawater into the air. The biggest single problem with this proposal is that there appear to be no readily available analysis of the costs and benefits. How would we power the sprays? If that were done through solar, or wind energy, that would be more helpful than doing it by burning diesel. How long would such salt-laden clouds last? We simply don’t know. Some might argue that clouds contain water, which is itself a powerful blanket material. That is true, and it is why cloudy nights are warmer than cloudless ones, nevertheless there should still be a significant net benefit, because the reflection to space is of visible and even ultraviolet light, whereas the blanket effect merely affects infrared light, of a moderate frequency range, although it does it 24 hrs/day.

How about space reflectors? The cost would be enormous, although there is one possibility. Suppose one could develop solar-powered lasers that were sufficiently powerful to ablate space junk. You do not need a major mirror, but merely a large surface area. If you could boil away the metal and condense it as dust, that would still qualify as area. As an aside, it does not need to be that bright, although it should be. If sunlight is absorbed in space, that is almost as effective because the dust then re-radiates the energy as heat, and most will be directed to space.

It is also possible that there could be other minor ways of contributing. Thus the concept of everyone painting their roof white, as suggested by physics Nobel laureate Steven Chu, or even using aluminium for roofs is often rejected as making contributions that are too small, nevertheless, every ordinary householder still has to paint their roof or replace it at some time, and does it hurt to be helpful?

Another possibility might be to inject something into the exhaust of jet engines at high altitude. The point here is the jets are flying anyway, and you would end with micron-sized white dust in the contrails. Materials have to be chosen so they do not form slags in the engines, hence the choice depends on technical details of which I am unaware. Materials, in order of higher melting point dust, might range from a mercaptan or dialkyl sulphide (no solid, but would produce sulphuric acid on oxidation, which would condense water vapour and make clouds), diethyl zinc (which would produce white zinc oxide, melting point 1975 ^oC, and hence would remain as a dust in any working engine) or alkyl silanes (which would produce silicon dioxide, similar to volcanic ash, with a melting point above 1600 ^oC. The actual melting point depends on the form of the solid).

Finally, there is also the possibility of growing certain crops that give off gases that may increase cloud cover. Thus certain marine algae are reported to give off mercaptans, which would be photooxidised to sulphuric acid and thus form clouds, and also each molecule would remove some number of photons from the solar input. Removing ultraviolet also removes the corresponding heat input.

An important point to consider is that all light that is not reflected to space is either converted to heat eventually, or is locked away as chemical energy. The Earth continually presents to the sun a cross-sectional area of about 40.5 x 10^12 square meters. You can work out for yourself the area required to reduce the solar input by whatever per centage you wish, after correcting for whatever efficiency you choose, but as you can see, it is a very large area, no matter what.

It may strike you that trying to solve this problem this way is simply too difficult and expensive. Possibly, but my argument is we are wrong to rely on one king hit. For me, this is the problem to be solved by a thousand cuts, so to speak. In later posts I shall add thoughts on the other alternatives. However, the above thoughts seem to me to form the start of a concept. There are some things we might try that either might have other benefits or are reasonably cheap to put into practice, and these should take some form of precedence. But the overall conclusion is clear: there is simply insufficient data available to reach any reasonable conclusion.