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?

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.

Global warming: Heads in the sand, everyone!

One of the most popular topics for “head in the sand” thinking is global warming. Never mind the evidence; only too many assert that the models are wrong, so there is no need to worry. What I find annoying about this is there is no evidence supplied to support the assertion, although you can usually see a quote in some “scientific” journal. You will see some claims about “peer review” but that is irrelevant. Some time I shall post about peer review, but for the present that does not matter because who asserts something is irrelevant to deciding truth; it is what is said that matters, and specifically, what the evidence is to support it.

Very recently we have heard more on this topic, and the climate change models have been shown to be almost certainly wrong. Not that the deniers can take any bows; the models were wrong in the other direction. Up until now, the modellers have argued that by the end of the century sea levels would rise a meter, mainly due to thermal expansion of the oceans and the loss of minor glaciers, with a small effect due to fragmentation of ice sheets in Greenland and Antarctica due to “bottom-warming”, i.e. ice melted by contact with warmer ocean currents, together with a little “top-warming” from sunlight.

Now they have become aware that the major ice sheets are undergoing top-warming from contact with moist warm air. The net result is that the ice sheets are thinning for major distances from the sea, and the end-position if this net heating is left to go on unchanged is now considered to be a sea level rise of up to sixty meters. In New Zealand, where I live, the cost assigned to the loss of houses due to a 1.5 meter sea level rise was assessed as about $20 billion. That does not include commercial buildings, and worse, it does not include required changes to infrastructure because here quite a number of roads run along beside the sea. This helps the view for tourists and holiday-makers, but only too many of the low bits of those roads will have to be moved. Worse, the high bits through tortured hilly regions will have to be rebuilt. Certainly, these roads are high enough but they have to connect with something. It only takes a small section to be submerged, and if the low-lying land is flat enough, then there may be real problems connecting a new fragment with existing sections that climb up steep hills. Worse than that, the reason these roads run alongside the sea is that often this is the only flat land, and a new coastline will have the sea smashing into mountainous land. A road-building nightmare.

The next thing we see is that we have numerous exhortations that society must as a priority reduce emissions of greenhouse gases. Sorry, but this won’t work, although it will reduce the rate at which the problem gets worse. The reason is this. At present we have net melting of ice. The polar bear habitat is shrinking rapidly, and this can only happen by the heat input melting more ice than can be laid down through winter snow. This is clear evidence the planet is receiving net heat input.

For the planet to heat, there has to be net power input, which is the difference between the solar input and the radiated output from the planet. If the heat input is constant, that can only arise through something keeping in more than it did previously. The agent that is doing that is the blanket of greenhouse gases covering the planet.

My point is, if we totally stopped producing greenhouse gases tomorrow, the current rate or heat retention, and hence the current rate of melting, would continue. The usual way of returning to balance between heat in and heat out would be that the planet warms until at the new temperature it radiates enough out. However, ice melts with the water being at the same temperature as the ice so the overall warming only partially occurs.

The problem is, there is a constant heat input from the sun, and the temperature is determined by the rate at which the planet radiates out excess energy. While it is a grey body, the rate at which it radiates heat from surface is proportional to the fourth power of the temperature. Accordingly the temperature rises until heat out equals heat in, and the system is at equilibrium. (Of course, this only happens on an overall average, because the planet does not get uniform heating, and there are weather events and ocean currents that move heat around.)

Think of yourself in summer lying in bed, and you are quite comfortable. Now someone throws three blankets over the bed. Are you going to stay comfortable? Not likely. Even if we stopped greenhouse gas emissions completely, in this example it is no better than that someone stopping throwing extra blankets on the bed. We cannot make further headway until someone starts to remove the extra blankets. That is what has to happen. The trouble is, so far governments cannot even stop the throwing on of extra blankets.

Greenhouse warming – a refusal by some to analyse the science.

One thing that has annoyed me recently is the efforts of the so-called climate change skeptics. One of the rules of science is, nature is always right. You may have the most wonderful theory, but if nature disagrees, you are wrong. Evidence is key. The problem then is, the evidence has to be correctly interpreted and consistent with known physics.

An example that has annoyed me is the continued assertions that the temperatures have not risen significantly since 1990, and they produce graphs of temperatures taken at some place to prove their point. So, what is wrong with that? Well, for one thing, NASA has produced considerable evidence that temperatures have risen across the planet. Ha, the skeptics say, you have your figures, we have ours, so at worst it is unproven. The argument seems to be, our figures are no worse than yours. So, what is the problem here?

Actually, it is not really selected data. They are probably correct that their data is no worse. Their measurements may even be more accurate. The problem is that temperature is not the relevant measurement, but rather power flows are. If power in exceeds power out, since energy is conserved, something is heating. Prolonged measurements over the oceans during a period that is alleged to have had stable temperatures have shown (Lyman et al., 2010. Nature 465:334-337.) that between 1993 and 2008 there was an increase in the heat power delivered to the oceans of 0.64 w.m-2. A fifteen year period has to be sufficient to exclude random weather fluctuations during a “bad year”. The oceans were picked on because they are free of a number of other variables.

So, why were some temperatures not rising? There is more than one reason. One is that as you pump more heat into the atmosphere, there is more energy available, and that means that winds are stronger. In turn, that means better mixing of the air. Thus where I live has had some record cold temperatures, the reason being that stronger storms, etc, have transported more air from the Antarctic, and that is decidedly colder than the air normally about here. Of course, by moving colder air from the Antarctic, warmer air has gone in to replace it, and the Antarctic is warming. If it were only the air, that would not be a problem, in fact it might even be good because it would take more moisture over the Antarctic and deposit more snow, which works against sea-level rising, but unfortunately that is not the issue. Extra heat going into the oceans gets to work on the polar ice shelves, which melts them. There is another reason: as you melt ice, heat is absorbed but there is no temperature increase. You don’t believe me? Get a thermometer and put an ice/water mix on an element and heat. The thermometer will stay at 0 oC until the ice has gone, as long as the mixing is good. Melting ice absorbs heat, and unfortunately, the melting of polar ice is to some extent ameliorating the temperature increase.

Another claim that annoyed me was the observation that the upper troposphere was cooling, and this allegedly showed there was no global warming. That is just plain wrong. In the greenhouse mechanism, infrared radiation from the ground is absorbed by CO2. At this point, there is no change of temperature in the gas. The CO2 has become vibrationally excited, but that is all. Now, one of two things can happen. It can re-emit radiation in any direction, or it can collide with another gas molecule, in which case the vibrational energy may be converted to kinetic energy shared between the two molecules, and this does lead to heat. (Most of the atmospheric heat is actually from convection or water vapour condensation). However, the same works in reverse: collisions of molecules can excite vibrational states. If the new gas molecules can emit infrared, they have that option, but isolated oxygen and nitrogen cannot by themselves. Therefore, extra CO2 at the top of the troposphere actually cools it by radiating more heat to space, derived from collisions with other gas molecules, and that lowers the temperature of that part of the atmosphere. So, why does the planet warm? The extra CO2 at the bottom radiates energy back to Earth, and that excites the radiators there, and these radiate back to the atmosphere, but at the same rate they did before. The problem is, before they took heat from the environment and radiated it, thus cooling. Now that cooling is slowed because they are taking their energy in part from returning infrared radiation from the CO2 in the atmosphere. Thus the CO2 acts more like a blanket cast over the planet; technically it does not heat the planet, but it slows its cooling, which is the same effect.

What annoys me is that some seem to think that observing what the physics predicts is somehow evidence that the physics is wrong! Bizarre! You cannot prove a proposition is wrong by citing evidence required by the proposition.

The problem here is obvious: an urge to say what is convenient overcomes the need to do the proper thinking and properly analyze the evidence. Unfortunately, this urge will have some serious consequences.

I apologize to those who expected a post yesterday. I had an alternative post, an announcement, but unfortunately what I intended to announce did not happen!

 

Science, the nature of theory, and global warming.

My summery slumbers have passed, but while having them, I had web discussions, including one on the nature of time. (More on that in a later post.) I also got entangled in a discussion on global warming, and got one comment that really annoyed me: I was accused of being logical. It was suggested that how you feel is more important. Well, how you feel cannot influence nature. Unfortunately, it seems to influence politicians, who end up deciding. So what I thought I would do is post on the nature of theory. I have written an ebook on what theory is and how to form theories, and while the name I gave it was not one that would attract a lot of readers (Aristotelian methodology in the physical sciences) it was no worse than “How to form a theory”. Before some readers turn off, I started that ebook with this thought: everyone has theories. For most, they are not that important, e.g. a theory on who trashed the letterbox. Nevertheless, the principles of how to go about it should be the same.

In the above ebook, I gave global warming as an example of where science has failed, not because we do not understand it, but rather the public has not really been presented with the issue properly. One comment about global warming is that scientists have not resolved the issue. That depends on what you mean by “resolved”. Thus one person said scientists are still working on relativity. Yes, they are, but that does not mean that what we have is wrong. The scientific process is to continually check with nature. So, what I want to do in some of my posts this year is try to give an impression of what science is.

The first thing it is not is mathematics. Mathematics are required, and part of the problem is that only too often scientists do not state clearly what they are saying, preferring to leave a raft of maths for the few who are closely in the field. This is definitely not helpful. Nor are TV shows that imply that theories are only made by stunning mathematics. That is simply not true.

The essence of science is a sequence of simple statements, which are the premises. For me, the correct methodology was invented by Aristotle, and the tragedy is, Aristotle made some howling mistakes by overlooking his own methodology. Aristotle’s methodology is to examine nature and from it, draw the premises, then apply logic to the statements to draw some conclusions, check with observation, and if the hypothesis still stands up, try to determine whether there are any other hypotheses that could have given equivalent predictions. Proof of a concept is only possible if one can say, “if and only if X, then Y”, in which case observing Y is the proof. Part of the problem lies in the “only”; part lies in seeing the wood for the trees. One of the first steps in analyzing a problem is to try to reduce it to its essentials by avoiding complicating features. This does not mean that complicating features should be ignored; rather it means we try to find a means of avoiding them until we can sort out the basics. If we do not get the basics right, there is no point in worrying about complicating factors.

To consider global warming, the first thing to do is put aside the kilotonnes of published data. Instead, in order to focus on the critical points, try modeling something simpler. Consider a room in your house in winter, and consider you have an electric bar heater. Suppose you set it to 1 Kw and turn it on. That will deliver 1 kilojoule of heat per second. Now, suppose doors are open or not open. Obviously, if they are open, the heat can move elsewhere through the house, so the temperature will be slower to rise. Nevertheless you know it will, because you know there is 1 kilojoule per second of heat being liberated.

The condition for long term constant temperature (equilibrium) is
(P in) – (P o) = 0
where (P in) is the power in and (P o) is the power out, both at equilibrium. This works for a room, or a planet. Why power? Because we are looking to see whether the temperature will remain constant or change, and to do that we need to see whether the system is changing, i.e. gaining or losing heat. To detect change, we usually consider differentials, and power is the differential of energy with respect to time. Because we are looking at differentials, we can say, if and only if the power flow into a system equals the power flow out is it at an energy equilibrium. We can use this to prove equilibrium, or otherwise, but we may have to be careful because certain other energy flows, such as radioactive decay, may be generated internally. So, what can we say about Earth? What Lyman et al. found was there is a net power input of 0.64 watts per square meter of ocean surface. That means the system cannot be at equilibrium.

We now need a statement that could account for this. Because the net warming effect is recent, the cause must be recent. The “greenhouse” hypothesis is that humanity has put additional infrared absorbers into the air, and these absorb a small fraction of the infrared radiation that would otherwise go to space, then re-emit the radiation in random directions. Accordingly, a certain fraction is returned to earth. The physics are very clear that this happens; the question is, is it sufficient to account for the 0.64 W? If so, power into the ground increases by (P b) and the power out decreases by (P b). This has the effect of adding 2 (P b) to the left hand side of our previous equation, so we must add the same to the right hand side, and the equation is now
(P in + P b) – (P o – P b) = 2 (P b)
The system is now not in equilibrium, and there is a net power input.
The next question is, is there any other cause possible for (P b)? One obvious one is that the sun could have changed output. It has done this before, for example, the “Little Ice Age” was caused by the sun’s output dropping with a huge decrease in sunspot activity. However, NASA has also been monitoring stellar output, and this cannot account for (P b). There are few other changes possible other than atmospheric composition for radiation over the ocean, so the answer is reasonably clear: the planet is warming and these gases are the only plausible cause. Note what we have done. We are concerned about a change, so we have selected a variable that measures change. We want to keep the possible “red herrings” to a minimum, so the measurements have been carried out over the ocean, where buildings, land development, deforestation, etc are irrelevant. By isolating the key variable and minimizing possible confusing data, we have a clear answer.

So, what do we do about it? Well, that requires a further set of theories, each one giving an effect to a proposed cause, and we have to choose. And that is why I believe we need the general population to have some idea as to how to evaluate theories, because soon we will have no choice. Do nothing, and we lose our coastal cities, coastal roads and coastal agricultural land up to maybe forty meters, and face a totally different climate. Putting your head in the sand and feeling differently will not cool the planet.

* Lyman, J. M. and 7 others, 2010. Nature 465:334-337.