Fuel for Legacy Vehicles in a “Carbon-free” Environment

Electric vehicles will not solve our emissions problem: there are over a billion petroleum driven vehicles, and they will not go away any time soon. Additionally, people have a current investment, and while billionaires might throw away their vehicles, most ordinary people will not change unless they can sell what they have, which in turn means someone else is using it. This suggests the combustion motor is not yet finished, and the CO2emissions will continue for a long time yet. That gives us a rather awkward problem, and as noted in the previous posts on global warming, there is no quick fix. One of the more obvious contributions could be biofuels. Yes, you still burn carbon, but the carbon came from the atmosphere. There will also be processing energy, but often that can come from the byproducts of the process. At this point I should add a caveat: I have spent quite a bit of my professional life researching this route so perhaps I have a degree of bias.

The first point is that it will be wrong to take grain and make alcohol for fuel, other than as a way of getting rid of spare or spoiled grain. The world will also have a food shortage, especially if the sea levels start rising, because much of the most productive land is low-lying. If we want to grow biomass, we need an area of land roughly equivalent to the area used for food production, and that land is not there. There are wastelands, but they tend to be non-productive. However, that does not mean we cannot grow biomass for fuel; it merely states there is nowhere nearly enough. Again, there is no single fix.

What you get depends critically on how you do it, and what your biomass is. Of the various processes, I prefer hydrothermal processing, which involves heating the biomass in water up to supercritical temperatures with some additional conditions. In effect, this greatly accelerates the processes that formed oil naturally. Corresponding pyrolysis will break down plastics, and in general high quality fuel is obtainable. The organic fraction of municipal refuse could also be used to make fuel, and in my ebook “Biofuel” I calculated that refuse could produce roughly seven litres per week per person. Not huge, but still a contribution, and it helps solve the landfill problem. However, the best options that I can think of include macroalgae and microalgae. Macroalgae would have to be cultivated, but in the 1970s the US navy carried out an exercise that grew macroalgae on “submerged rafts” in the open Pacific, with nutrients from the sea floor brought up from wind and wave action. Currently there is work being carried out growing microalgae in tanks, etc, in various parts of the world. In principle, microalgae could be grown in the open ocean, if we knew how to harvest it.

I was involved in one project that used microalgae grown in sewage treatment plants. Here there should have been a double benefit – sewage has to be treated so the ponds are already there, and the process cleans up the nitrogen and phosphate that would otherwise be dumped into the sea, thus polluting it. The process could also use sewage sludge, and the phosphate, in principle, was recoverable. A downside was that the system would need more area than the average treatment plant because the residence time is somewhat longer than the current time, which seems designed to remove the worst of the oxygen demand then chuck everything out to sea, or wherever. This process went nowhere; the venture needed to refinance and unfortunately they left it too late, namely shortly after the Lehman collapse.

From the technical point of view, this hydrothermal technology is rather immature. What you get can critically depend on exactly how you do it. You end up with a thick brown fluid, from which you can obtain a number of products. Your petrol fraction is generally light aromatics, with a research octane number (RON) of about 140, and the diesel fraction can have a cetane number approaching 100 (because the main components are straight chain C15 or C17 saturated hydrocarbons. Cetane is the C16 equivalent.) These are superb fuels, however while current motors would run very well on them, they are not optimal.

We can consider ethanol as an example. It has an RON somewhere in the vicinity of 120 – 130. People say ethanol is not much of a fuel because its energy content is significantly lower than hydrocarbons, and that is correct, but energy is not the whole story because efficiency also counts. The average petrol motor is rather inefficient and most of the energy comes out as heat. The work you can get out depends on the change of pressure times volume, so the efficiency can be significantly improved by increasing the compression ratio. However, if the compression is too great, you get pre-ignition. The modern motor is designed to run well with an octane number of about 91, with some a bit higher. That is because they are designed to use the most of the distillate from crude oil. Another advantage of ethanol is you can blend in some water with it, which absorbs heat and dramatically increases the pressure. So ethanol and oxygenates can be used.

So the story with biofuels is very similar to the problems with electric vehicles; the best options badly need more research and development. At present, it looks as if they will not get it in time. Once you have your process, it usually takes at least ten years to get a demonstration plant operating. Not a good thought, is it?

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Non-Battery Powered Electric Vehicles

If vehicles always drive on a given route, power can be provided externally. Trams and trains have done this for a long time, and it is also possible to embed an electric power source into roads and power vehicles by induction. My personal view is commercial interests will make this latter option rather untenable. So while external power canreplace quite a bit of fossil fuel consumption, self-contained portable sources are required.

In the previous posts, I have argued that transport cannot be totally filled by battery powered electric vehicles because there is insufficient material available to make the batteries, and it will not be very economically viable to own a recharging site for long distance driving. The obvious alternative is the fuel cell. The battery works by supplying electricity that separates ions and converts them to a form that can recombine the ions later, and hence supply electricity. The alternative is to simply provide the materials that will generate the ions and make the electricity. This is the fuel cell, and effectively you burn something, but instead of making heat, you generate electric current. The simplest such fuel cells include the conversion of hydrogen with air to water. To run this sort of vehicle, you would refill your hydrogen tank in much the same way you refill a CNG powered car with methane. There are various arguments about how safe that is. If you have ever worked with hydrogen, you will know it leaks faster than any other gas, and it explodes with a wide range of air mixtures, but on the other hand it also diffuses away faster. Since the product is water (also a greenhouse gas, but one that is quickly cycled away, thanks to rain, etc) this seems to solve everything. Once again, the range would not be very large because cylinders can only hold so much gas. On the other hand, work has been going on to lock the hydrogen into another form. One such form is ammonia. You could actually run a spark ignition motor on ammonia (but not what you buy at a store, which is 2 – 5% ammonia in water), but it also has considerable potential for a fuel cell. However, someone would still have to develop the fuel cell. The problem here is that fuel cells need a lot more work before they are satisfactory, and while the fuel refilling could be like the current service station, there may be serious compatibility problems and big changes would be required to suppliers’ stations.

Another problem is the fuel still has to be made. Hydrogen can be made by electrolysing water, but you are back to the electricity requirements noted for batteries. The other way we get hydrogen is to steam reform oil (or natural gas) and we are back to the same problem of making CO2. There is, of course, no problem if we have nuclear energy, but otherwise the energy issues of the previous post apply, and we may need even more electricity because with an additional intermediate, we have to allow for inefficiencies.

As it happens, hydrogen will also run spark ignition engines. As a fuel, it has problems, including a rather high air to fuel ratio (a minimum of 34/1, although because it runs well lean, it can be as high as 180/1) and because hydrogen is a gas, it occupies more volume prior to ignition. High-pressure fuel injection can overcome this. However there is also the danger of pre-ignition or backfires if there are hot spots. Another problem might include hydrogen getting by the rings into the crankcase, where ignition, if it were to occur, could be a real problem. My personal view is, if you are going to use hydrogen you are better off using it for a fuel cell, mainly because it is over three times more efficient, and in theory could approach five times more efficient. You should aim to get the most work out of your hydrogen.

A range of other fuel cells are potentially available, most of them “burning” metal in air to make the electricity. This has a big advantage because air is available everywhere so you do not need to compress it. In my novel Red Gold, set on Mars, I suggested an aluminium chlorine fuel cell. The reason for this was: there is no significant free oxygen in the thin Martian atmosphere; the method I suggested for refining metals, etc. would make a lot of aluminium and chlorine anyway; chlorine happens to be a liquid at Martian temperatures so no pressure vessels would be required; aluminium/air would not work because aluminium forms an oxide surface that stops it from oxidising, but no such protection is present with chlorine; aluminium gives up three electrons (lithium only 1) so it is theoretically more energy dense; finally, aluminium ions move very sluggishly in oxygenated solutions, but not so if chlorine is the underpinning negative ion. That, of course, would not be appropriate for Earth as the last thing you want would be chlorine escaping.

This leaves us with a problem. In principle, fuel cells can ease the battery problem, especially for heavy equipment, but a lot of work has to be done to ensure it is potentially a solution. Then you have to decide on what sort of fuel cells, which in turn depends on how you are going to make the fuel. We have to balance convenience for the user with convenience for the supplier. We would like to make the fewest changes possible, but that may not be possible. One advantage of the fuel cell is that the materials limitations noted for batteries probably do not apply to fuel cells, but that may be simply because we have not developed the cells properly yet, so we have yet to find the limitations. The simplest approach is to embark on research and development programs to solve this problem. It was quite remarkable how quickly nuclear bombs were developed once we got started. We could solve the technical problems, given urgency to be accepted by the politicians. But they do not seem to want to solve this now. There is no easy answer here.

Where will the Energy for Electric Vehicles come from?

In the previous post, I looked at the issues involved with replacing all motor vehicles with electric vehicles, and noted that is impossible with what we know now because the necessary materials are just not there. Of course there may be new battery technology developed, but there is another issue: from whence the energy? From international energy statistics, petroleum liquids have the equivalent energy of 53 trillion kWh. Since the electric vehicle is more efficient we can divide that number by about three, so we need almost 18 trillion kWh. (The issue is more complicated by whether we are trying to replace petroleum or solve the transport issue, since some petroleum products are used for heating, but for simplicity I am going to stick with that figure.) If we were going to do that by solar energy, the sunlight gives according to Wikipedia, on average about 3.5 – 7 kWh/m2per day. That needs about five trillion square meters devoted to solar energy to replace petroleum products. The Earth’s area is 510 trillion square meters, so we need about 1% of the surface area devoted solely to this, if the cells are 100% efficient. The highest efficiencies so far (Data from NREL) come from four junctions, gallium arsenide, and a concentrator where 46.6% has been reached. For single junction cells using gallium arsenide, we get 35% efficiency, while silicon cells have reached 27.6%. If silicon, we need 4% of the world’s area.

It is, of course, a bit worse than this because 70% of the world’s surface is ocean, and we can eliminate the polar regions, and we can eliminate the farmland, and we should eliminate the wild-life habitats, and we can probably assume that places like the Sahara or the Himalayas are not available and anyway would be too dusty, too windy, too snowy. Solar energy drops efficiency quite dramatically if the collectors get covered in dust or snow. So, before we get all enthusiastic about solar, note that while it can contribute, equally there are problems. One issue that is seldom mentioned is how we find the materials to make such a huge number of panels. In this context, the world supply of gallium is 180 tonne/a, so basically we should be back to silicon, which is one of the most plentiful elements. (In one of my novels I made a lot of someone finding a source of gallium otherwise overlooked. I feel good about that!). We don’t know how critical element supply would be because currently there is a lot of development work going on on solar conversion and we cannot tell what we will find. The final problem is that latitude also plays a part; in southern England we would be struggling to get the bottom of the range listed above on a sunny day, and of course there are many cloudy days. Accordingly, assuming we do not put the collectors on floats, the required area is starting to get up to 10% of the land area, including highly unsuitable land. We just cannot do it.

That does not mean solar in of no use. One place to put solar panels is on the roof of your house. Superficially, if every motorist did this, the problem is solved, apart from the long-distance driving, at least in the low latitude areas. The difficulty here is that the sun shines in the day, when the commuter uses his car. The energy could be stored, but we have just doubled the battery requirements, and they were already out of hand. You could sell to the power to the grid, and buy power back at night, and there is merit in this as it helps with daylight loads, except that the power companies have to make money, and of course, the greatest normal power requirements are in winter at the beginning and end of the day, when solar is not contributing. So yes, solar power can help, but it is not a single fix. Also, peak power loads are a problem. If the company needs capacity for that, where does it come from? Right now, burning gas or coal. If your electric vehicle is purchased to save the environment from greenhouse gas emission, that is pointless if extra power has to be generated from coal or oil.

My personal view on this is that while renewables are going to be helpful, if we want to stop emitting carbon dioxide when making energy, we have to go partially either nuclear or thermonuclear. My personal preference is for fusion reactors, but we do not know how to make them yet. The main problem with fission reactors is the disposal of waste, and the potential for making materials for bombs. We can get around that if we restrict ourselves to thorium reactors, because the products, while still radioactive, decay much more quickly, and finally you cannot make a thorium bomb. Another benefit of thorium reactors is they cannot get the runaway problems as seen at Chernobyl and Fukushima; they really are very much safer. The problem now is we have not developed thorium fission reactors because everyone uses uranium to make plutonium for bombs.

Even if we manage to get sufficient electricity, the next problem is transmission of this huge increase in electricity. In most countries, the major transmission lines will not take it, and would have to be replaced or supplemented. Not impossible, butat the cost of a lot of carbon dioxide being emitted in making the metals, and transferring them, because massive electric vehicles cannot precede the ability to shift electricity. Again, this is not a problem per se, but it is if we do not get organised quickly. The next problem is to get it to houses. “Slow charging” overnight is probably adequate, even for a tesla. If you can charge it fully in an hour at just over 40 amps, you should need only 3 amps overnight. Not difficult. However, the retail sale of electricity for vehicles travelling is not so easy. It is hard to put figures on this because I don’t know what the demand will be, but charging a vehicle for over an hour means no more than about ten vehicles per day per outlet. It is hard to make money out of that, so you need a lot of outlets. If you have a hundred outlets, you service a thousand cars, say, per day. Still not a lot of profit there and you need a parking lot and some excellent organization. You are also drawing 4,000 amps, so you need a fairly good power supply. Not an enticing proposition for investment.

The point I am trying to make here is that the problem is very large. We have built a monstrous infrastructure around oil, and in the normal circumstances, when we have to change, that industry would go slowly and another would slowly take its place. We don’t have that luxury if we want to save our coastal cities. Yes, everyone can “do their bit”, and that buys time if we all do it, but we also need some bigger help, in organization, research, development and money. It is time for the politicians to stop thinking about the next election, insulting the opposition, and start thinking about their country.

Climate Change: the Potential for Electric Vehicles

In my last post, I discussed the need for action over climate change. Suppose we decide to be more responsible, what can we do? There are several issues, but the main ones include is a solution fit for purpose, which includes will the general population see it as such and does it achieve a useful goal, and is it actually possible? To illustrate what I mean, consider the “easy option”: scrap motor cars and replace with electric vehicles. At first sight, that is easy and you will probably think there is no technological advance needed. Well, think again on both of those. Let’s put numbers on the problem: according to Wikipedia, the number of motor vehicles in the world is 1.015 billion.

Now, to consider the issue, “fit for purpose”, in New Zealand, anyway, and I suspect North America will be worse, people drive fairly long distances at least some of the time. One solution to that problem is to make people stop doing that. This is from the “sacrifices have to be made” school. As it happens, energy consumption probably will have to be reduced, but that does not mean that we need some politicians to say which form of energy consumption is forbidden to you. If people must use less, they should have a choice in what form they give it up.

There are two “niches” of electric vehicle, and as examples I shall pick on the Tesla and the Nissan Leaf. The Tesla currently claims a 400 km range (and intends to provide a 500 km range) per charge, while what you get from the Leaf is highly dependent on driving conditions, but it reaches a little over 100 km with average city driving. Basically, the Leaf would be great for someone wishing to commute daily, but not use it for distance driving. As an aside, the dependency on conditions will affect all such cars; we know about this aspect of the Leaf because there is more information available as more Leafs have been sold. The difference in range is simply because the Leaf’s battery is much smaller (198 cells compared with Tesla’s 7,104).

So why doesn’t the Leaf put in more cells? That is partly because of the problem of charging, and partly because of price and suitability for a chosen niche. A review of electric vehicles in our local paper brought up these facts. There are statements that the 400 k type car be charged at home overnight, “just like your mobile phone”. Well, not quite. While that sounds easy enough, where are you going to do it? Your home may have a garage, so maybe there. The mobile connector comes with adaptors that permit charging at 40 amps. Um, does your house have 40 amp rating to your garage, or maybe 50 amp to be on the safe side because you don’t want to accidentally throw the fuse and be walking to wherever next morning? Our reviewer found that to fully charge such a vehicle with 400 km range using his garage power rating took the best part of two days. Using a fast charger as available here, it took 75 minutes. Yes, you can charge these batteries relatively quickly if you can deliver the required current. The reason the Leaf has such a small battery capacity is so that it can be charged overnight with the average domestic power supply, and it can also be recharged while at work if the owner can “graze” on some power supply. Needless to say, once someone published figures like that, someone else challenged them, and pointed out that a steady 7 kW overnight would do it and “nearly two days” was wrong. Unfortunately, power itself is not the whole story because the current has to be rectified and voltage has to be kept to within a specific range. Apply an over-voltage, and different chemistry starts up in the battery that is not reversible, which means you greatly shorten your battery life.

There is some good news on batteries, though. The batteries do decay with time, and while details are not available, one estimate is that Tesla batteries should still be 90% effective after 8 years, which is quite respectable, while the Leaf claims its batteries should last ten years in a workable condition. Thus we have two types of vehicles: an expensive vehicle that can do anything a current vehicle can do on the open highway, provided there are adequate rapid charging sites. Here “adequate” takes on significance; refilling with petrol takes a few minutes and sometimes there is overcrowding. Will there be enough cables if it takes 75 minutes? How much will “site time” charge?

Then there is the question of how you use it. Do you carry big loads? Ferry lots of children? Go off road, or go camping? If so, the current electric vehicle is not for you. So the question then is, for those who see the electric vehicle as all you have to do to solve the transport problem, are they advocating no off-road activity, no camping, no serious loads? The answer is probably, yes. So, do we want to give up our lifestyle? If the answer is no. are there options? Of course not everyone wants to do those sort of things, so there will most certainly be quite sizable niches that can be filled with electric vehicles. Finally, there will be one further problem: the poorer people cannot afford new Teslas, or even new Leafs. They own second hand cars and cannot afford to simply throw that investment away. The liquid fuel transport economy will be with us for a lot longer yet.

The next question is, is it feasible to replace all cars with electric vehicles? For the purpose of analysis, I shall assume everyone wants a Tesla type driving capacity, as the next step is to put numbers on the problem. The battery weight is listed as 540 kg, which means to do the replacement, we would need something approaching half a billion tonne of batteries. That is not all lithium, but it includes “a small amount of cobalt and nickel”. If we interpret that as about 2% the weight each of the batteries, we need about ten million tonne of cobalt and nickel. World production of cobalt in 2017 was about 110,000 tonne, while nickel was over ten times this. Both metals, however, are fully used now, and the cobalt supply is deficient by about two orders of magnitude if all cobalt was devoted to electric vehicles. Unlikely. Oops! That is more than a small problem. It is not a problem right now because electric vehicles comprise only a very small fraction of the market, but it is insoluble. There is a strict limit on the possible supply of cobalt because as far as I know, there are no cobalt ores. Most cobalt comes from the Democratic Republic of Congo, as a by-product of copper mining. There would also be a significant demand for copper. The Tesla has two motors, one of which is 300 kW, so considerable amount of copper would be used, but world production of copper is about 24,000 Mt annually, so that is not an immediate problem, but may be in the long term. The annual supply of graphite is 126,000 t. Given that there will be more graphite used than lithium, this is a serious problem, however there is no shortage of carbon; the problem is converting carbon to graphite. That is quite a subtle problem; as it happens I know how to get close to the required fraction of graphite, but as yet, not economically.

So there are technological problems. Maybe they are soluble, but doing so introduces another problem, as exemplified by finding an alternative to cobalt. Cobalt is needed to give the non-graphitic electrode enough strength that the battery will have adequate lifetimes with good charging rates. So that is probably non-negotiable. There are alternatives, but so far none match the current battery type used by Tesla. Further, to develop a new battery and test its lifetime over ten years takes: you guessed it; the last part alone takes ten years, assuming your first pick works. Therein lies the overall problem; politicians have wasted nearly 30 years on the basis that it was not urgent. However, technical development does take a long time. For that reason it is wrong to lazily say, electric vehicles, or some other solution, will solve the problem. They will most certainly help, but we have to back many more options.

Science and Climate Change

In the previous post, I questioned whether science is being carried out properly. You may well wonder, then, when this week the Intergovernmental Panel on Climate Change issued a rather depressing report, and a rather awkward challenge: according to their report, the world needed to limit the temperature rise to 1.5 degrees C between now and 2050, and to do that, it needed to cut carbon emissions by 45% by 2030, and net zero by 2050. Even then significant amounts of carbon have to be removed from the atmosphere. The first question is, then, is this real, and if so, why has the IPCC suddenly reduced the tolerable emissions? If their scientists previously predicted seriously lower requirements, why should these be considered better? There are two simple answers. The first is the lesser requirements were based on the assumption that nations would promptly reduce emissions. Most actually increased them. The second is more complicated.

The physics have been verified many times. However, predicting the effects is another matter. The qualitative effects are easily predicted, but to put numbers on them requires very complicated modelling. The planet is not an ideal object, and the calculation is best thought of as an estimate. What has probably happened is their modelling made a projection of what would happen, and they did this long enough ago that now that they can compare prediction with where we are now. That tells them how good the various constants they put into the model were. Such a comparison is somewhat difficult, but there are clear signs in our observations, and things are worse than we might hope for.

So, what are we going to do? Nothing dramatic is going to happen on 2040, or 2050. Change will be gradual, but its progress will be unstoppable unless very dramatic changes in our behaviour are made. The technical challenges here are immense. However, there are a number of important decisions to be taken because we are running short of time due to previous inaction. Do we want to defend what we have? Do we want to attempt to do it through sacrificing our life style, or do we want to attempt a more aggressive approach? Can we get sufficient agreement that anything we try will be properly implemented? Worst of all, do we know what our options are? Of these questions, I am convinced that through inaction, and in part the structural defects of academic science, the answer to the last question is no.

The original factor of required emissions reduction was set at 1990 as a reference point. What eventuated was that very few countries actually reduced any emissions, and most increased them. The few that did reduce them did that by closing coal-fired electricity generation and opted for burning natural gas. This really achieves little, and would have happened anyway. Europe did that, although France is a notable exception to this in that it has had significant nuclear power for a long time. Nuclear power has its problems, but carbon emissions are not one of them. The countries of the Soviet Union have also actually had emission reductions, although this is as much as anything due to the collapse of their economies as they made the rather stupid attempt to convert to “free market economics” which permitted a small number of oligarchs to cream the economy, sell off what they could, use what was usable, pay negligible wages and export their profits so they could purchase foreign football clubs. That reduced carbon emissions, but it is hardly a model to follow.

There is worse news. Most people by now have recognized that Donald Trump and the Republican party do not believe in global warming, while a number of other countries that are only beginning to industrialize want the right to emit their share of CO2 and are on a path to burn coal. Some equatorial countries are hell-bent on tearing down their rain forest, while warming in Siberia will release huge amounts of methane, which is about thirty times more potent than CO2. Further, if we are to totally change our way of life, we shall have to dismantle the energy-related infrastructure from the last fifty years or so (earlier material has probably already been retired) and replace it, which, at the very least will require billions of tonnes of carbon to make the required metals.

There will be some fairly predictable cries. Vegetarians will tell everyone to give up meat. Cyclists will tell everyone they should stop driving cars. In short, everyone will have ideas where someone else gives up whatever. One problem is that people tend to want to go for “the magic bullet”, the one fix to fix them all. Thus everyone should switch to driving electric vehicles. In the long term, yes, but you cannot take all those current vehicles off the road, and despite what some say, heavy trucks, major farm and construction equipment, and aircraft are going to run on hydrocarbons for the foreseeable future. People talk about hydrogen, but hydrogen currently requires massive steel bottles (unless you are NASA, or unless you can get hydrides to act reversibly). And, of course, there is a shortage of material to make enough batteries. Yes, electric vehicles, cycling, public transport and being a vegetarian are all noble contributions, but they are just that. Wind and solar power, together with some other sources, are highly desirable, but I suspect that something else, such as nuclear power must be adopted more aggressively. In this context, Germany closing down such reactors is not helpful either.

Removing CO2 from the atmosphere is not that easy either. There have been proposals to absorb it from the effluent gases of coal-fired power stations. Such scrubbing is not 100% efficient, but even if it were, it is not dealing with what is already there. My guess is, that can only be managed by plants in sufficient scale. While not extremely efficient, once going they look after themselves. Eventually you have to do something with the biomass, but restoring all the tropical rain forests would achieve something in the short term. My personal view is the best chances are to grow algae. The sea has a huge area and while we still have to learn how to do it, it is plausible, and the resultant biomass could be used to make biofuel.

No, it is not going to be easy. The real question is, can we be bothered trying to save what we have?

Science Communication and the 2018 Australasian Astrobiology Meeting

Earlier this week I presented a talk at the 2018 Australasian Astrobiology Meeting, with the objective of showing where life might be found elsewhere in the Universe, and as a consequence I shall do a number of posts here to expand on what I thought about this meeting. One presentation that made me think about how to start this series actually came near the end, and the topic included why do scientists write blogs like this for the general public? I thought about this a little, and I think at least part of the answer, at least for me, is to show how science works, and how scientists think. The fact of the matter is that there are a number of topics where the gap between what scientists think and what the general public think is very large. An obvious one is climate change; the presenter came up with a figure that something like 50% of the general public don’t think that carbon dioxide is responsible for climate change while I think the figures she showed were that 98% of scientists are convinced it does. So why is there a difference, and what should be done about it?

In my opinion, there are two major ways to go wrong. The first is to simply take someone else’s word. In these days, you can find someone who will say anything. The problem then is that while it is all very well to say look at the evidence, most of the time the evidence is inaccessible, and even if you overcome that, the average person cannot make head or tail of it. Accordingly, you have to trust someone to interpret it for you. The second way to go wrong is to get swamped with information. The data can be confusing, but the key is to find critical data. This means that when making a decision as to what causes what, you put aside facts that can mean a lot of different things, and concentrate on those that have, at best, one explanation. Now the average person cannot recognize that, but they can recognize whether the “expert” recognizes it. As an example of a critical fact, back to climate change. The fact that I regard as critical is that there was a long-term series of measurements that showed the world’s oceans were receiving a net power input of 0.6 watt per square meter. That may not sound like much, but multiply it over the earth’s ocean area, and it is a rather awful lot of heat.

Another difficulty is that for any given piece of information, either there may be several interpretations for what caused it, or there may be issues assigning significance. As a specific example from the conference, try to answer the question, “Are we alone”? The answer from Seth Shostak, from SETI, is, so far, yes, at least to the extent we have no evidence to the contrary, but of course if you were looking for radio transmissions, Earth would have failed to show signs until about a hundred years ago. There were a number of other reasons given, but one of the points Seth made was a civilization at a modest distance would have to devote a few hundred MW power to send us a signal. Why would they do that? This reminds me of what I wrote in one of my SF novels. The exercise is a waste of time because everyone is listening; listening is cheap but nobody is sending, and simple economics kills the scheme.

As Seth showed, there are an awful lot of reasons why SETI is not finding anything, and that proves nothing. Absence of evidence is not evidence of absence, but merely evidence that you haven’t hit the magic button yet. Which gets me back to scientific arguments. You will hear people say science cannot prove anything. That is rubbish. The second law of thermodynamics proves conclusively that if you put your dinner on the table it won’t spontaneously drop a couple of degrees in temperature as it shoots upwards and smears itself over the ceiling.

As an example of the problems involved with conveying such information, consider what it takes to get a proof? Basically, a theory starts with a statement. There are several forms of this, but the one I prefer is you say, “If theory A is correct, and I do a set of experiments B, under conditions C, and if B and C are very large sets, then theory A will predict a set of results R. You do the experiments and collect a large set of observations O. Now, if there is no element of O that is not an element of R, then your theory is plausible. If the sets are large enough, they are very plausible, but you still have to be careful you have an adequate range of conditions. Thus Newtonian mechanics are correct within a useful range of conditions, but expand that enough and you need either relativity or quantum mechanics. You can, however, prove a theory if you replace “if” in the above with “if and only if”.

Of course, that could be said more simply. You could say a theory is plausible if every time you use it, what you see complies with your theory’s predictions, and you can prove a theory if you can show there is no alternative, although that is usually very difficult. So why do scientists not write in the simpler form? The answer is precision. The example I used above is general so it can be reduced to a simpler form, but sometimes the statements only apply under very special circumstances, and now the qualifiers can make for very turgid prose. The takeaway message now is, while a scientist likes to write in a way that is more precise, if you want to have notice taken, you have to be somewhat less formal. What do you think? Is that right?

Back to the conference, in the case of SETI. Seth will not be proven wrong, ever, because the hypothesis that there are civilizations out there but they are not broadcasting to us in a way we can detect cannot be faulted. So for the next few weeks I shall look more at what I gathered from this conference.

Can We Feed an Expanded Population?

One argument you often see is that our farmland can easily feed even more people and that our technology will see that famines are a thing of the past. I am going to suggest that this may be an overenthusiastic view of our ability. First, the world is losing a surprising amount of good soil every year, to water and wind erosion. Seawater rising will remove a lot of prime agricultural land, but there is a much worse problem that needs attention. The 18th May edition of Science had some information that might give cause to rethink any optimistic view. Our high intensity agriculture depends on keeping pests, weeds and fungi at bay, and much of that currently depends on the heavy use of certain chemicals. The problem is what we are trying to keep at bay are gradually evolving resistance to our agents.

Looking at fungicides first, there are basically four classes of fungicides licensed for use, and some of these, such as the azoles, have a number of variations, but the variations tend to be those to differentiate the compounds from someone else’s, and to get around patents. The fundamental activity usually comes from one chemical group. As an example from antibiotics, there are a large number of variation on penicillin, but they all have beta lactams, and it is the beta lactams that give the functionality, so when bugs evolve that can tolerate beta lactams, the whole set of such penicillin-like drugs becomes ineffective. For fungi, the industrial scale production of single crops in some regions optimises the chance of a fungus developing a resistance, and there appears to be the possibility of gene transfer between fungi.

This has some other downstream issues. Thus medical advances lead to people having a much better chance of survival through cancer treatments, but they then become more susceptible to fungi. Apparently Candida auris is now resistant to all clinical antifungals, and is a worse threat in hospitals because it can survive most standard decontamination procedures. A number of other fungi are very threatening in clinical situations.

So what can be done about fungi? Obviously, seeking new antifungals is desirable, but this is a slow process because before letting such new chemicals out into the environment, we have to be confident that there will really be benefits and the chemicals are sufficiently effective under all circumstances, and we also need to know there are no unintended consequences.

Insecticides and herbicides (and following the article in Science, these will be collectively termed pesticides) have the same problem. It was estimated that even now the evolution of such resistance costs billions of dollars in the US. With regard to weeds, in 1996 plants were produced that were not harmed by glyphosate, and the effectiveness of this led to over 90% of US maize, soy and cotton being planted with such plants. (Some will recall the fact that some were bred so the plants did not produce viable seed, and further seed had to be purchased from the company that developed the plant.) Now there are at least forty serious weeds that have developed resistance to glyphosate. Plants have been engineered that are resistant to chemicals mimicking previous herbicides but the weeds are defeating that. Weed species have evolved to resist every known herbicide, and no herbicide has been developed with a new mode of action over the last thirty years.

In agriculture, it is easy to see how this situation could arise. When you spray a crop, not every part of every plant gets the same amount of spray. Some of what you don’t want will survive in places where the dose was less than enough. From the farmer’s point of view, this does not matter because enough of the pests have been dealt with that his return is not hurt by the few that survive. However, the fact that some always survive is just what evolution needs to develop life forms capable of resisting the chemicals.

So, what to do? Obviously, more effort is required, but here we meet some problems that might be intractable. Major companies have to invest large amounts of money to provide a possible solution, and they will only do so when there are likely to be guaranteed very large sales. However, to defeat resistance, it is most desirable to pulse agents, thus using agent A one year, agent B the next, and no repeat for a number of years. That maximises the chance of avoiding the generation of further resistance, but what company wants to participate in the sort of sales future? We could try natural procedures and live with the fact that yields are lower, but that implies we really do not want to eat that much more, which in turn suggests population growth needs to be curbed. Unfortunately, there are no easy answers.