Wednesday, 26 February 2014

Milankovitch and the ‘Earth History’ Perspective on Climate Change, or ‘Why We Should All Stop Worrying About Global Warming’



It is, I believe, a little known fact that we are currently living in an ice age. It is called the Pliocene-Quaternary Glaciation and it started about 2.58 million years ago.

That this may come as a bit of a surprise to some people is probably due to the fact that it is generally believed – at least by people of my own generation – that the last ice age came to an end around 10,000 years ago. This, however, now turns out to have been an erroneous interpretation of the then available data by 19th century geologists who had neither the evidence nor the theoretical basis to distinguish between whole or completed ice ages and oscillating phases within an ice age, in which, it seems, temperature ranges are seldom if ever constant.

In fact, the current ice age can probably be best characterised as one in which relatively long periods of glacial advance, resulting from global cooling, are punctuated by shorter period of glacial retreat, resulting from global warming. What geologists in the 19th century took as the end of an ice age was only, therefore, the end of the most recent period of glaciation, which lasted around 100,000 years, and the beginning of the current interglacial period, which has so far lasted around 10,000 years.
Over the last 2.58 million years there have therefore been many such cycles of glacial advance and interglacial retreat. With respect to true ice ages, however, there is evidence of only five in earth’s history, as shown in Figure 1 – although there may have been others for which there is no geological evidence, or for which the geological evidence has not yet been found. 

Name
Period
Huronian
2.4 to 2.1 Billion years ago
Cryogenian
850 to 630 Million years ago
Andean-Saharan
460 to 420 Million years ago
Karoo
360 to 260 Million years ago
Pliocene-Quaternary
2.8 Million years ago to present
Figure 1: Known Ice Ages

What is truly remarkable about these five ices ages, however, is how very little we seem to know about any of them – at least outside scientific and academic circles. If you look up each one on Google, for instance, you will find out:
  •  that evidence of the existence of the Huronian ice age, which formed during the Proterozoic eon, comes from unique rock formations in an area north of Lake Huron.
  • that the Cryogenian ice age, which, as its name suggests, was probably the most severe of the known ice ages, covered the entire planet – turning it into snowball in space – and that it was probably brought to an end by tectonic or volcanic activity, which threw enough green-house gases into the atmosphere to start a period of global warming – though this, of course, is largely conjecture.
  • that of the Andean-Saharan ice age, nothing appears to be known whatsoever.
  •  that occurring at the onset of the Devonian period, when land based plants were beginning to cover the continents, the Karoo ice age was very possibly caused by this new vegetation extracting carbon dioxide from the atmosphere, thus reducing the greenhouse effect and starting a period of global cooling – which, again, is pure speculation.
  • that of the Pliocene-Quaternary glaciation, the only thing that is known for certain is that it is still going on.
That we know this – when the 19th century geologists did not – is because we now have ice-core samples from Antarctica and the Greenland ice-sheet which show that, around 2.58 million years ago, average global temperatures began to decline below the Vostok mean (named after the research station in Antarctica where this benchmark was first established), and that, despite the increasing amplitude of the fluctuations, they have continued to decline ever since, as shown in Figure 2.


Figure 2: Ice Core Record of the Pliocene-Quaternary Glaciation
 
Significantly, the increase in the amplitude of the oscillation tells us is that, throughout the ice age so far, the periods of glaciation have not only been getting colder but longer, with the average length of cycle having increased from 41,000 years during the first half of the ice age – as calculated to date – to around 100,000 years in the second half. What we don’t know, of course, is whether this trend is still continuing, or whether it has already reached the bottom. What we do know, however, is that, whether or not global temperatures are now on the upturn, further oscillations will occur. Without very significant external intervention, trends like this don’t simply come to an end. 

Because the current interglacial period has already lasted for around 10,000 years, we also know that we are due to enter a new period of glaciation sometime soon – even though the word ‘soon’, here, is intended in climatological terms, which could mean anything between 1 and 5,000 years. 

In fact, it was the imminence of the next cycle of glaciation which sparked much of the current research into climate change. When, in the 1980s – as a result of work on ice-core samples – it was first discovered that we are still in an ice age and that a return to a period of glaciation was due, this was very much everyone’s principal fear. And it was then that a number of climatologists came forward with the idea that the emission of man-made greenhouse gases might delay this outcome. As a result, politicians throughout the developed world then channelled funds into research to discover whether this was, indeed, the case, only to be told by the researchers concerned that man-made greenhouse gases, and the global warming to which they gave rise, might themselves prove to be problem.

Since then, of course, nearly all our attention has been focused on addressing this issue. Billions of dollars have been spent, both on fundamental research and on the technologies and changes to our economy that would be required to rein back man-made global warming. Far less attention has been given, however, to the more fundamental issue that for the last 2.58 million years the earth has been going through repeated cycles of global warming and cooling without any help from ourselves.

Indeed, for those who are not already aware of it, it is important to note that the whole of our civilisation, from the development of agriculture, around 10,000 years ago, to the creation of all the technological marvels we see around us today, has taken place entirely within the current interglacial period, a timespan so short that if you look for it on the graph in Figure 2, it is so hard up against the right-hand vertical axis that it is lost within the width of the printed line. Rather than have any causal effect on the cyclical pattern of climate change that is clearly indiscernible within the graph, our civilisation, in fact, would not have been possible at all without this brief interglacial respite between the much larger cycles of global freezing.

Of even greater importance, however, is the fact that being cyclical and entirely natural in origin, the pattern of climate change we see in Figure 2 is almost certainly driven by something which, in addition to being immensely powerful, is also fundamentally cyclical in nature. Given, therefore, that there is only one object in our solar system which meets both these requirements – exhibiting both immense power and cyclical fluctuations – it is almost certainly the case that this underlying pattern has something to do with our sun – or, more precisely, with our planet’s orbit around it.

To understand how this could be possibly, however, one first has to appreciate that the earth’s solar orbit is not uniform, being subject to cyclical variations known as the Milankovitch Cycles, named after the Serbian astronomer and mathematician, Milutin Milankovitch, who first postulated and demonstrated their existence while serving as a prisoner in an Austrian POW camp during the first world war.

The Milankovitch Cycles are the result of three fundamental, though probably little known facts about the earth’s orbit:
  1. The fact that the solar or tropical year, on which our calendar year is based, is slightly shorter than the earth’s orbital or sidereal year, thus giving rise to a phenomenon known as planetary precession.
  2. The fact that the earth not only tilts on its axis at different degrees to the sun during the cycle of each tropical year, thus defining our seasons, but that the tilt itself is subject to cyclical fluctuations.
  3. The fact that, due to the gravitation pull of the other planets, particularly Jupiter and Saturn, the eccentricity of the earth’s elliptical orbit – the degree to which it diverges from the perfectly circular – is also subject to cyclical variations.
I shall explain each of these in turn, starting with the first, which has the largest effect upon our climate, and is the factor which other factors therefore either augment or partially serve to nullify.

So let’s start with the basics.

If asked to define the term ‘year’, I suspect that most people would say that it is the amount of time it takes for the earth to complete one whole orbit of the sun. This, however, is what is known as the sidereal year. Our calendar year, in contrast, is based on the tropical year, which is measured from equinox to equinox: seasonal phenomena which result from the fact that the earth not only turns on its access, but wobbles on it, tilting first one way and then the other. What is probably less well known, however, is the fact that that these two ‘years’ are not quite the same.

If, for instance, we were to select a point in the earth’s orbit at which we could say that both years began – a point which, for convenience, we might choose to have coincide with one of the earth’s two equinoxes – then even after our wobbling planet had completed one whole inclinational cycle – leaning first one way and then other, before returning to the perpendicular again – in terms of its sidereal journey around the sun, it would still not yet have returned to its original starting point. Admittedly it only falls short by about 20 minutes. But cumulatively these annual discrepancies add up, with the earth slipping further and further back around its orbital path, until eventually – 25,772 years later – it slips all the way back to meet itself one lap behind, at which point it may have notched up 25,772 tropical years, but has only completed 25,771 actual orbits.

But what possible effect could this have on our climate, you ask. Well, if our planet’s orbit were perfectly circular, it wouldn’t have any effect at all. But, as we know, the earth’s orbit is elliptical. This means that there are times when it is further away from the sun than other times. And should these times also coincide with times when, due to its tilt, the earth is also pointing away from the sun, the effect is magnified as shown in Figure 3.


Figure 3: Solstices at Extremes of Ellipse

Here we see a situation in which both the summer and winter solstices are at the extremes of the ellipse, while the spring and autumn equinoxes are therefore at the closest points to the sun. In this configuration, winters are likely to be the coldest in the entire cycle. With the earth furthest from the sun and tilting away, less light reaches the winter hemisphere than at any other time. Summers are also likely to be poor, in that, although the summer hemisphere is pointing towards the sun, the earth is so much further away that the amount of light reaching the surface is still less than during any other summer. The only periods of respite in this cycle of rather gloomy seasons, in fact, are likely be the springs and the autumns, which, occurring at points at which the earth is closest to the sun, are likely to be warmer than usual, merging almost imperceptibly with the rather tepid summers, so that the only seasons that actually stand out – and this for their harshness – are likely to be the winters.

This is in marked contrast to the opposite configuration, as shown in Figure 4, in which the winter and summer solstices occur when the earth is closest to the sun. In this case, the summers are likely to be the hottest in the cycle, with the winters at their mildness, merging almost imperceptibly with the rather poor springs and autumns resulting from the equinoxes now being at their furthest points from the sun. In fact, in this configuration, the only seasons which are likely to stand out are the summers.


Figure 4: Equinoxes at Extremes of Ellipse

As this is based on the certainty of physical laws, geometry and mathematics, unlike many other factors affecting our climate, this, therefore, is an ever constant heartbeat, something one can absolutely depend on, and almost certainly constitutes our climate’s most fundamental cyclical base. If there were no other factors involved, in fact, this cyclical coincidence of tilt and elliptical extremes would result in the earth’s climate simply being divided into four periods, each of 6,443 years, in two of which the planet would experience cycles of overall cooling, while in the other two it would experience cycles of overall warming.

As already stated, however, Milankovitch identified two further factors which affect this underlying pattern. The first of these concerns variations in axial obliquity, or the degree to which the earth tilts one way and then the other during its tilt cycle, which varies between 22.1° and 24.5° over a period of 41,000 years. This means that during some of its precession cycles, and for quite long periods at a stretch, the earth points further away from the sun during its winter solstices than during other cycles, making these years even colder. What is also quite interesting here is that this cycle of 41,000 years just happens to be the same as the cycle of glaciation and retreat in the first half of the current ice age, as shown in Figure 2

This is then further complicated  by a third factor which concerns the shape of the earth’s orbit, itself, which is pulled in different directions, becoming more or less elliptical, depending on the alignment of the other planets in the solar system. These are again entirely determined by physical laws, geometry and mathematics, and are therefore wholly predictable, operating within an overall cycle of 413,000 years – although, within this, there are smaller cycles of around 100,000 depending on planetary alignment. 

To produce an overall model of our planet’s underlying climatic cycle, therefore, all it would seem that we now need to do is work out how all these factors interact. For depending upon the way in which their individual peaks and troughs coincide – or not, as the case may be – there are clearly going to be times when their effects reinforce and magnify each other, and times when they counteract and perhaps even nullify each other. The problem, however, is that although the Milankovitch cycles clearly constitute a fundamental part of this overall pattern, no one has yet come up with a model based on them that fully accounts for all the available climatological data, even though climatologists, today, include in their calculations two addition orbital factors – apsidal precession and orbital inclination – which were not taken into account by Milankovitch himself.

What this means, therefore, is that there have to be additional factors affecting the cycle which go beyond the pure mathematics of moving bodies in space. And two of these, it is generally believed, are feedback loops – one positive and one negative – resulting from glaciation itself.

The positive feedback loop, known as increasing albedo, results from the fact that snow and ice reflect more of the sun’s energy back out into space than grey ocean and brown earth. The further the polar ice caps extend, therefore, the more of the sun’s energy is lost in this way, and the cooler the planet becomes, raising the question, in fact,  as to how, once a period of glaciation has started, the earth ever manages to escape its grip. Indeed, increasing albedo is quite possibly one of reasons why periods of glaciation gradually get longer and deeper over time, each cycle starting from a lower base.

What stops this downward slide going on indefinitely, however, is believed to be a counter-acting or negative feedback loop which results from the fact that, as the ice sheet extends over more and more of the planet, this reduces the amount of both land-based vegetation and oceanic algae which would otherwise absorb carbon dioxide. As a result, more and more greenhouse gases build up in the atmosphere; the planet starts to warm; and the ice sheet retreats. 

What this amounts to, therefore, is another natural cycle of cooling and warming which, in a way, sits on top of and further augments the Milankovitch cycles, making the overall picture even more complicated. Even taking these feedback loops into account, however, climatologists have still not yet been able to produce a model which completely satisfies all the empirical data. Other factors – some of them possibly still to be identified – have got to be involved. What makes climatologists so concerned about the current situation, however, is that, according to the model, as I have so far presented it, greenhouse gases should only build up in the atmosphere towards the end of a period of glaciation. They should actually be at their lowest towards the end of an interglacial period. What this suggests, therefore, is that although our own contribution to greenhouse gas emissions is relatively low – accounting for less than 3% of the 793 billion metric tons of carbon dioxide deposited in the atmosphere each year, according to the International Panel on Climate Change – and although most of this (782 billion metric tons) is then reabsorbed by the world’s forests and oceans in yet another purely natural cycle, through deforestation and the burning of fossil fuels, we, ourselves, have nevertheless become another factor in the equation. 

So what’s new, you may ask. Climatologists have been telling us this for the last twenty-odd years. And so they have. What they haven’t done, however, is provide us with the kind of climatological background and historical perspective that I have been trying to provide here.  By omitting such factors as the Milankovitch cycles from their presentations, and by failing to mention that we are still actually living in an ice age, intentionally or otherwise, they have therefore given the impression that without the greenhouse gases which we ourselves are generating, our climate would be more or less stable. More to the point, by ignoring the fact that without these anthropogenic greenhouse gases we would almost certainly be heading into another cycle of glaciation, they make it seem as if man-made global warming is entirely a ‘bad thing’. But consider the alternative. For, make no mistake, if we were to prevent man-made global warming from bringing an end to the cycles of warming and cooling shown in Figure 2, then sooner or later we would enter another period of global cooling. 

As a result, the ice cap at the north pole would gradually extend further south again until, eventually, if geological evidence is anything to go by, it would reach a latitude of around 40° N, making much of Northern Europe and North America uninhabitable. Ice hundreds of metres thick would cover all of Canada and the northern states of the USA, including all of New England, New York, Michigan, Wisconsin, North Dakota and Montana. In Europe, it could easily extend as far south as the Alps and the Rhone valley – which was glaciated during the last cycle of global cooling – and would certainly cover much of northern Germany, Poland and Russia.

Admittedly, the alternative – if we allow global warming to continue – isn’t much better. In this case, the polar ice caps would continue to recede until, eventually, they would disappear altogether, returning the planet to something like its normal condition. I say this because, in the 2.1 billion years since the Huronian Ice Age, ice has only actually covered the earth’s poles for 17% of that time. What this also means, however, is that sea levels would continue to rise, with some whole countries disappearing beneath the waves. Indeed, without massive new sea defences, some of the world’s largest cities, such as London and New York, would also be at risk.

The fact is, however, that of these two possible futures, global warming offers the better prospect for survival. It may be difficult and cost a great deal of money. For as we have seen during the floods in Britain recently, defending oneself against the forces of nature is a mammoth task. It is a lot easier, however, than trying to maintain agricultural production in a country covered by millions of tons of ice.

This being the case, the question one has to ask, therefore, is why we are so exercised by the second of these two possible outcomes but seem not to care about the first, especially given the fact that if, by some miracle, we were able to prevent global warming from bringing the Pliocene-Quaternary Glaciation to a permanent end, we would actually be responsible for plunging ourselves into another period of global freezing. 

Part of the answer, of course, is simply one of timescale. For, as already mentioned, another cycle of glaciation might not happen for another thousand years or more, and even then it would take some time for the ice sheet to reach its maximum depth and coverage. In the last cycle, for instance, its didn’t reach its peak until 85,000 years in. Given that our entire civilization is only 10,000 years old, this doesn’t therefore fill one with immediate concern. The effects of global warming, in contrast – or so we are told – are already being felt. It makes sense, therefore, to concentrate on the problem at hand.

Eminently pragmatic though this strategy may seem, however, I have my doubts as to whether it actually plays any significant part in most people’s thinking. Indeed, most people, I’m fairly sure, have absolutely no idea that another cycle of glaciation is even an option. Another possibility, therefore, is that, sceptical of our ability to reverse the current trend, both climatologists and politicians alike have more or less concluded that a return to glaciation is no longer a threat: a conclusion which would certainly explain why, over the last thirty years, it has so completely slipped off the radar.

Not, of course, that one can blame politicians for doubting our collective will to combat climate change. For even if governments around the world were actually to take steps to reduce greenhouse gas emissions – rather than merely talking about them – this wouldn’t reduce the volume of such gases already in the atmosphere. In fact, unless emissions were reduced to a level lower than the rate of oceanic absorption, this residual volume would still continue to rise. If these greenhouse gases have the effect upon our climate which so many people claim they have, it is hard to see, therefore, how this effect could be reversed without a drastic reduction in economic activity: something which would almost certainly result in the deaths of millions, if not billions of people.

The question which this naturally prompts, therefore, is why, if curtailing the emissions of man-made green-house gases is so politically out of the question, politicians throughout the democratic world still largely support a green agenda, trotting out all the right words and phrases on camera, even if no real action is being taken behind closed doors. A very large part of the answer to this question, however, has to do with the way in which the campaign against man-made global warming was initially set in motion. For if one remembers back to the early years of this century, prior to the financial collapse of 2008, when venerable presenters such as David Attenborough stood in front of collapsing glaciers and bemoaned the fate of the polar bear, the way in which the issue was presented was not, primarily, as a matter of scientific concern, but as one of moral urgency. It may not have been the intention of Sir David or his producers to deliberately play upon our feelings for furry animals, but that, of course, is what they did, and with entirely predictable results. For not only did we, too, start to bemoan the way in which we – or, more specifically, right-of-centre governments and big business – were raping and destroying the planet, we also made it impossible for our politicians to adopt any other stance.

And to make matters worse, this popular media campaign to enlist our support in a world-wide movement to reverse global warming didn’t stop there. For having engaged our sympathy and provoked our moral outrage, it also triggered what I can only describe as our predisposition to mythologise. For having lifted global warming out of its historical context and attributed it purely to the activities of man, the barely disguised subtext with which we were then presented was inescapable: mankind had been given a green and pleasant land – a veritable Garden of Eden – which, in our infinite folly and wickedness, we were now in the process of turning into a watery grave. The appeal to the biblical – to the flood and Noah’s Ark, in fact – couldn’t have been more blatant. More importantly, however, it stirred in us that self-flagellating fascination with the eschatological which has haunted writers and artists for millennia, and which retains its place within our deepest fears even to this day.

The reasons for this dark obsession at the heart of our religious and artistic culture are, of course, fairly obvious. By linking our own deaths to the extinction of the species, we imbue our individual lives with a tragic significance they otherwise lack. This only works, however, if our extinction is our own fault. Being wiped out by a rogue asteroid, for instance, provides no such narrative fulfilment. Indeed, it only goes to show just how meaningless our lives are – or were. To be meaningful, our destruction has to follow from our own actions, and has to be seen as a just punishment. And the destruction of the planet as a result of man-made global warming fits this requirement perfectly.

In fact, in many ways, it is the almost perfect artistic expression of the many ambivalent feelings we have about our stewardship of the planet over the last the 10,000 years, during which period we have:

  • Used up most of the world’s non-renewable resources, squandering them on the manufacture of material possessions we don’t need, don’t used, and for which, in many case, we don’t even have enough room in our houses;
  • Driven countless other species to extinction, or to a marginal existence in which their numbers can be counted in thousands, if not hundreds;
  • So increased our own population that the earth is barely able to support the 7.2 billion people it currently has to feed, without the adverse climate conditions which global warming will almost certainly bring about.
So numerous are our crimes against the planet, indeed – at least in our own fevered, anthropocentric imagination – that it is hardly any wonder that there are those on the extreme wing of the green movement who have a tendency regard human beings as something more akin to a parasitic virus: one that is slowly consuming the body it has infested. Nor is it particularly surprising, given such attitudes, that advocates of radical action to combat global warning often sound more like religious zealots than political campaigners, vilifying those who express any scepticism about their beliefs as ‘climate-change deniers’ and heretics.

The problem this presents for politicians, however, is that, having created this monster – or having at least given it the oxygen it needed to flourish – they cannot now distance themselves from it without being labelled as apostates. At the same time, they have also become increasingly aware of how little they can actually do to address the underlying problem, especially in a world recovering from an economic recession, in which growth and the balancing of budgets quite naturally take priority.

To make matters worse, they are also now being told that global temperatures over the last fifteen years have not increased in the way that climatologists predicted – remaining more or less static – which makes them question whether the models on which these predictions were based were correct. In fact, for most politicians today, the whole issue of climate change has become a disaster zone they enter at their peril.

But global warming is happening, right? Probably. 

And human beings are at least partly responsible, yeah? Again, probably. 

So there’s no real change in the underlying position? Correct.

The fact remains, however, that our climate models are incomplete. We do not know what caused the five ices ages of which we are aware, or what brought them to an end. We don’t even know what causes the cycles of warming and cooling within the current ice age. We know that the Milankovitch cycles are involved, as are various feedback loops resulting from glaciation, itself. But the model is incomplete. We still do not have a complete picture.

Indeed, I mentioned earlier that there are almost certainly other factors involved in climate change which may not yet have even been identified. One of these is almost certainly the sun itself, not just in the role it plays in determining the earth’s orbit, but in the energy it radiates, particularly in the form of sun spots or solar flares. These produce waves of ionised particles, known as the solar wind, which washes across the earth’s upper atmosphere, stripping out dust and other accumulated debris, thereby allowing more light to penetrate through to the surface, while at the same time interacting with the oxygen in the atmosphere to increase the amount of ozone, thus doubly contributing to global warming.

Unsurprisingly, this form of solar activity is again cyclical, though nobody really knows why. Nor is it quite as predictable as the Milankovitch cycles. Typically, solar cycles last around 22 years, with very little in the way of gaps between them. However, between Solar Cycle 23, which ended in early 2008, and Solar Cycle 24, which started in late 2009, there was a gap of nearly 2 years in which virtually no sun spots occurred, and in which global temperatures already began to fall, causing some climatologists to fear that this could actually have been the start of another Maunder Minimum.

This was a period which lasted from 1645 to 1715, in which sun spots became extremely rare, resulting in a period of global cooling often referred to as the Little Ice Age, which is still commemorated on many of our more traditional Christmas cards. Famously, the Thames in London froze over each year, allowing for the construction of an annual ice fair, which became a perennial feature of the capital’s economic and social life, providing both a market and various forms of entertainment from December through to March. 

So what am I saying? That another Maunder Minimum is going to come along and save us from the effects of global warming? Of course not. Such events are totally impossible to predict. But that’s the point. Given the incompleteness of our climate models, even our best guess at what is going to happen may be completely wrong. To spend our time and our energies worrying about global warming when (a) we can’t do anything about it, (b) it may not actually happen, and (c) it may not be a entirely bad thing if it does, is therefore the height of irrationality, especially when it is elevated to the status of a religion.

So what then? Do we just sit here and let the waves roll over us? No, there’s plenty of things we can do: things that are both rational and practical. Following the floods we have suffered in Britain this winter – which many people have attributed to global warming, though that, of course, is impossible to establish – we can start by improving our flood defences. Given that infrastructure projects are generally believed to be a good way to stimulate the economy, this would therefore be a very good way to spend a few billion pounds. It won’t stop global warming, of course, but it might just mitigate some of the effects – which is the point I’m trying to make.

To finish, therefore, I’d like to leave you with one further thought: that it is not changes to the environment that cause species to become extinct, but the failure of a species to adapt to the said changes.

Recently, I caught a news item which reported that US authorities are extremely worried about a species of Asian carp getting in the great lakes and displacing the indigenous species. They are therefore planning to spend billions of dollars to prevent this.

While watching the report, however, I couldn’t help thinking about an alternative approach. Instead of stopping the carp entering the lakes, they could stimulate a fishing industry to catch them and sell them to consumers. After all, carp are very good source of protein and omega 3, and, if prepared correctly, are very palatable. In Poland, I believe, they are served at Christmas as a seasonal delicacy. If caught in sufficient numbers, this would therefore stop them displacing other species and would create both food and employment at the same time. Only it takes is a bit of lateral thinking.

The problem, it seems to me, is that, too often, we think that our only responsible attitude to the environment is one of conservation. Nothing must be allowed to change, including our climate, even though we know, from earth’s history, that our climate is in constant flux. So we spend billions trying to prevent what cannot be prevented, rather than prepare for the changes we, ourselves, will need to make once the inevitable has happened. For, make no mistake, the carp will get into the great lakes. Sometimes, therefore, accepting change, and adapting to it is the best policy. Sometimes, indeed, it is the difference between survival and extinction.