Chapter 5

One Metre


My second favourite moment from the charming and beautifully animated film, Finding Nemo is when Marlin, having found the perfect spot for a hatchery shows, with pride, his expectant partner their view. From the coastal shelf, the seabed tumbles steeply down to the great yawning abyssal plain that stretches into the distant watery haze: the depths of the ocean foretelling the story to come without a word needing to be spoken. The efforts of a small team of computer animators manage to illustrate the all-embracing vastness of the ocean far more effectively than any TV documentary or piece of writing I have yet encountered. Call me a philistine if you wish, but I’m still a sucker for a good movie.

For the record, my favourite moment in Finding Nemo is when the little boy in the dentist’s waiting room lets his mouth fall open at the terrifying events taking place in the surgery the other side of the tropical fish tank. I love that bit.

Finding Nemo was about many things: love, courage, the beauty of the natural world, the uncaring attitude of certain humans and the ability of many different species to communicate (so it would seem – they certainly passed on messages more efficiently than many electronic systems). What finding Nemo was not about was encouraging children to go out and buy clownfish, but that’s what happened: “Sales of clownfish across America increased almost overnight, with eager parents harassing pet shops for a ‘Nemo’ of their own. But in contrast to the common goldfish, clownfish need a saltwater environment - plus a lot of complicated equipment - to survive. In the hands of inexperienced owners, countless fish perished.”[i] We have no way of telling whether any of the dominant messages in the film were taken up by movie-goers, however I would be willing to bet that once immersed again into a world of advertising, those messages would sadly have been pushed to the back of even the most caring child’s mind.

Whether it is from the use of explosives, the application of hydrogen cyanide or the casting and dragging of miles of fine meshed net; the pillaging of tropical waters to feed an insatiable desire for attractive, exotic fish in the front rooms of the richer nations’ consumers is big business. The death toll is so large from ocean to fish tank – the UN estimate that thirty percent of fish are killed in transit – that, were profit margins not so great, no one would be interested in doing this kind of thing on a large scale. According to the United Nations Environment Programme, 20 million tropical fish are removed from the sea each year, destined for fish tanks, along with 10 million other animals and 12 million specimens of coral – themselves collections of tiny animals called polyps[ii].

Over seventy percent of all tropical fish are caught in Indonesian waters, a figure that the third largest producer of carbon dioxide – if you include the amount of carbon released by forest destruction – would have to be proud of, if astonishingly bad environmental records were anything to be proud of.  On the flip side, and with astounding irony, the recipient of 73 percent of the world’s tropical fish is the USA; a nation that, at the time of writing, still produced more greenhouse gases than any other nation on Earth, and had done more than any other nation to prevent global agreements being struck to reduce the emissions of these greenhouse gases. When you combine the ills of coral cyanide poisoning to stun tropical fish with the increase in global temperatures caused by greenhouse gases bleaching (effectively killing) large areas of sensitive reef, then you find that the USA is number one in the world at destroying coral reefs. The gas-guzzling, coal burning, tropical fish keeping customer is not always right – especially when it comes to the care of the most important oceanic habitats on Earth.

If the 10cm long clownfish is a symbol of the way consumers disregard nature to feed their pastimes, then the one metre long cod is surely a symbol of the way consumers disregard nature to feed their appetites.

I mentioned the way that the consumption of meat seems to mirror economic development a while ago, but didn’t really touch on the problems that this brings. In a nutshell, meat requires a far greater amount of food energy to produce compared to plants grown directly for consumption – this can vary from about 5 times more, in the case of battery farmed chickens, to 25 times or more for the finest quality beef[iii]. The reason for this is simply that in order to rear an animal for food, you have to feed it; and animals, though efficient users of food energy need time in order to produce the muscle, which comprises the meat. The food that these animals eat has to be planted, usually using machinery that consumes oil and produces carbon dioxide; grown, mostly with the aid of fertilisers, pesticides, herbicides and so on, which take energy to produce and contribute to global heating; harvested, pre-processed and transported, just like all food destined directly for our kitchens, all of which produces more carbon dioxide; and then finally fed to the animal. If it takes ten pounds of grain or beets to produce one pound of food then, even allowing for the extra protein in animal muscle, the consumption of meat (and most dairy products, for that matter) is considerably worse for the environment than the consumption of vegetable matter. Not surprisingly – if you ignore the beneficial subsidies given to the meat and dairy industry by most of the governments in the industrial world – calorie for calorie, meat also costs far more to produce than fruit, vegetables or grains.

Which is a major reason why fishing is a vital part of the economies of so many countries, rich or poor, subsistence or industrial. Catching fish is an effective and relatively cheap way of feeding a population – or rather, it was.


What Are Cod?

Cod are just a type of fish, like humans are a type of mammal. That seems obvious, but it’s vitally important to realise that the reason cod are seen as such a significant type of fish, possibly above all others in importance, is simply because humans have probably eaten more of this type of fish than any other throughout history. We must learn to separate the economic or cultural significance of an animal, like the lion or blue whale; a plant, like an oak tree or stem of wheat; or any other organism, from what it actually is. Cod don’t know that they are economically or culturally significant, so for now, let’s just treat them as a type of fish.

There are only three true species of cod, namely the Atlantic, Greenland and Pacific. Each have distinctive breeding and schooling areas, such as the Barents Sea, and the waters around the Faroe Islands and Newfoundland; and each grow to a different maximum size – the Atlantic Cod being the biggest, at up to two metres in length, and the Pacific Cod the smallest at around 50cm. There are also a number of related species, which aren’t strictly cod, but do have many similar characteristics, including the Arctic Cod and Polar Cod. For commercial reasons, they are usually bunched into the same category, but then commerce never was very good at understanding nature!

Cod are known as demersal fish, meaning they spend most of their lives near to the bottom of the sea, feeding off other marine animals rather than the rich flora nearer to the ocean surface. Other types of demersal fish include haddock, whiting and monkfish. Far larger, by total mass, are the pelagic fish, which spend most of their time closer to the surface making the most of the food energy that derives from sunlight, which is largely absent from the deeper areas of the ocean. Pelagic fish include anchovies, sardines, mackerel and tuna, all of which are heavily fished wherever they occur in the world. As you can see, the vertical location of the fish doesn’t really have any bearing on size: tuna are some of the world’s largest fish, growing up to 2.5 metres in length and weighing in excess of 200kg, whereas adult anchovies are often no larger than the size of a child’s finger. The 1-2 metre Atlantic Cod is no match for the largest tuna, but at 20kg or more, is no tiddler; but when was the last time you saw a 20kg cod on a plate?

Cod can take five years or more before they reach full size, and may live for twenty or thirty years, no one is quite sure. If you catch a cod before it reaches full size then you are effectively catching a child or a growing teenager that has years of development ahead of it. Far worse than any ethical issue you may have about eating a youngster (most meat eaten is immature, be it from a cow, a pig or a tuna), because cod take at least three years before they are able to breed, by catching and eating cod before they reach sexual maturity then you are putting a brick wall in the way of the breeding cycle. This is now the acceptable face of fishing; according to the Scottish Fisheries Research Services: “By the time they reach two years old, young cod are fully exploited by the commercial fishery and many are caught long before they have the opportunity to spawn.”[iv]

Looking back to the beginnings of the mass fishing industry, one is filled with a sense that something was bound to go wrong. Tales of being able to drop buckets into the sea off of Newfoundland, the edge of the now defunct Grand Banks fishery, and bring them back up full to the brim with fish may not have been far off of the mark during the spawning season – although the explorer John Cabot’s pondering whether he could have walked from one side of the Atlantic to the other on the backs of the cod would almost certainly have come to grief. The point is, though, that the fishermen (and they were all men up to only a few years ago) really thought that there was an endless marine bounty. Fishing has always had an air of sentimentality, courage and permanence to it: men were made and broken, in dreadful conditions of isolation, wild storms, tiredness and constant pressure, only partly eased by songs, whisky and the thoughts of the family back home. Yet it most certainly was, and is a way of life: “Some guys couldn’t wait ‘til the last day of school so they could join the boat,” says Michael Coe, a former trawler skipper at Peterhead in the north east of Scotland, with genuine excitement.[v] A way of life, but nevertheless an industry, partaken of by thousands of boats across the great fishing grounds of the North Atlantic, Southern Ocean, Arabian Sea, Mediterranean and wherever a mass of marine life is there for the taking.

Atlantic Cod Catch

Figure 6: Atlantic Cod Catch by Fishing Area 1973-2006. Different colours denote the various fishing areas in the North Atlantic. (Source: ICES Fishstats :

But business and especially the search for profit now takes precedence in almost all formerly traditional and self-sustaining occupations. Whereas the shops and restaurants would formerly pay the going rate for fish and keep the industry alive for another season, it is now the supermarkets and fish-processors who call the shots – culling prices and progressively smaller fish until the skippers have no choice but to search deeper, further and with more technology; in the sad knowledge that their search for a high-volume, low price resource is destroying the very thing that kept them going for countless generations.

In the last 35 years, as shown vividly in Figure 6, the volume of Atlantic Cod retrieved from the water has plummeted from a high (for that period) of two million tonnes, to less than half that. The type of fish now being caught disguises the real volume – the smaller, immature fish may keep the industry ticking over for a few years, but the future looks barren. Fish colonies are in jeopardy around the world, with over half of all “stocks” (a term used by governments to imply humans own these natural habitats!) fished to full capacity, and a quarter in decline or endangered[vi]. There is such a fine line between “near” capacity and “over” capacity that it is fair to say that three quarters of the world’s major fish colonies are in an unsustainable state: they are not self-regulating – their numbers are being regulated by humans.

This is known as “The Tragedy Of The Commons”; the inevitable outcome of the oceans being used as an infinite resource, compounded by the wilful ignorance of a market economy that refuses to see the inevitable outcome of its greed. To paraphrase Garret Hardin, the originator of the concept: the business benefits from its ability to deny the truth even though society as a whole, of which it is a part, suffers[vii]. Amongst those people affected by the decimation of stocks, this denial is not so much malicious as pathological, according to Mark Kurlansky, author of “Cod”. They do not want to see this happening, so they just shut it off. Michael Coe says he only noticed a drop in the cod numbers around the year 2000; before then he claims he was able to fish pretty much the same areas year after year for over thirty years. This certainly doesn’t match the statistics. In 1996, the Canadian fisheries minister claimed that he knew “for sure” that the decline in the Newfoundland cod fisheries had ceased. It had done nothing of the sort – there were something like 15,000 cod counted, compared to 1.2 million ten years before.[viii]

The rapid expansion in farmed fish, or aquaculture, tells the true story of the panic growing within the fishing industry. Buy farmed fish and, just like farmed meat, it will have been fed far more protein than it actually brings to your plate – sucking smaller and smaller fish out of the sea. This “hidden” catch allows us to pretend there isn’t a problem at all. China is the global giant of aquaculture, accounting for two thirds of the world’s volume of farmed fish[ix]. Most of these fish are freshwater carp which, unlike in the fish-collecting West, are used as a major source of protein, especially in landlocked countries and inland areas. The global volume of farmed fish produced in 2004 was 48 million tonnes, out of a total of 140 million tonnes of fish consumed. Much of the fish production is carried out using plankton as a food source, but there is an increasing trend towards the production of carnivorous species that are fed on wild caught fish: two million tonnes of salmon, trout and related species were farmed in 2004, and well over two million tonnes of shrimp and prawn in the same year. These carnivorous species eat between two and five times more fish protein than they contain at the point that they are killed for food[x]. The farming of salmon and trout alone requires over eight million tonnes of wild caught fish, or about nine percent of the global catch.

There is a myth that industrial farming, whether of fish, meat or vegetables is an efficient way to produce food. No doubt it is a way to produce lots of food at a greater density and lower cost (mainly in terms of labour), but it is clear from the behaviour of the parties involved that industrial farming exists to maximise the profits of the giant “agribusiness” companies who swallow up vast areas of land, including thousands of small-scale farms every year. There is nothing sustainable about a high energy, high chemical, globalised corporate web: the energy required to farm in this way far exceeds the natural capacity of the soil or water to provide food. The myth of “sustainable” industrial farming is perpetuated by corporations such as Cargill – the largest grain exporter in the world – in order to show to the people of Earth that farming can only feed the mouths of the world if it is run by big business.

 Try telling that to the aboriginal tribes throughout the tropics, who have had their hunting grounds taken away and deforested in order to produce grain and graze cattle. Try telling that to the fishermen who have lost any chance of catching food for their families off the west coast of Africa because of the giant European pair-trawlers that blanket the oceans and scour them of life. Try telling that to the thousands who lost their lives and their homes in the Indian Ocean tsunami of 2004 that battered the coasts of east India and Sri Lanka; coasts that had previously been protected by mangroves, but are now dominated by shrimp farms as far as the eye can see.


Weaving A Fishy Web

Webs and loops fascinate scientists for all sorts of reasons. One reason is that they are potentially eternal: a loop will move round and around getting larger, smaller, faster or slower, or just staying the same. A web has things going into it, and out of it, but in the main is self-contained with each part of it being dependent in some way on the other parts. Here are a couple of examples.

Let’s consider Chris, who likes to go skiing: regularly travelling from his generous suburban house in Boston, to a drop-dead gorgeous winter chalet in Aspen, Colorado. Getting there wasn’t too easy a few decades ago, but the tourist industry wants people to go skiing because that’s good for the companies who sell skiing holidays, so airports have been built in the most remote locations. Chris can take a plane from Boston to Denver, then another one to Aspen, with only a short taxi trip at either end. Very convenient. The problem here is that he is rather dependent on there being snow when he arrives, otherwise he may have to be content with enjoying the scenery, as well as partaking of lots of après-walk drinks. Flying, as most people know, is a sure-fire way of boosting the amount of carbon dioxide, as well as a few other greenhouse gases, in the atmosphere. Not only does it take a lot of energy to keep a hunk of metal in the air, various chemical reactions from the aircraft’s contrails, especially in the upper atmosphere, make this effect all the more significant. If you are one of the few scientists who don’t believe that our greenhouse gas emissions are heating the Earth up, and you haven’t got the funds from an oil company, or a car manufacturer resting in your bank account, then you might want to skip this bit: for everyone else who has realised that our emissions are heating the Earth up (even the conservative Intergovernmental Panel on Climate Change are 80-90 percent sure[xi]) this is what the process looks like:

1) Person takes flights from Boston to Aspen

2) Emissions from aircraft cause atmosphere to heat up

3) Higher atmospheric temperature means that snow melts quicker

4) Less snow means that less sun is reflected and more is absorbed

5) Earth heats up, causing atmosphere to heat up more

6) Return to step 3.

Stages 3 to 6 are known as a feedback loop. I admit that it is greatly simplified but the basic facts are correct, and it exhibits two things that everyone needs to understand about feedback loops: first, at least one part of the process goes round in a cycle forever, or until some end point is reached (for instance, all the snow has melted); second, many loops can be made more intense by having inputs, such as people continuing to fly to Aspen (steps 1 and 2), speeding up the snow melting process. Even without the additional flying, the loop 3 to 6 is a positive feedback loop, in that it is adding to the effect each time it goes round. A negative feedback loop is one that gets weaker with each cycle: if the land underneath the snow were as white as the snow itself, and the flying stopped, the loop would quickly break down and, in the absence of global warming, the snow would return.

Most people learnt about food chains at school: Fish 1 is eaten by Fish 2 which, in turn is eaten by Fish 3 and so on. In this food chain, each fish occupies a different trophic, or food, level. This can easily become a loop if, when Fish 3 dies its body decays to be eaten by Fish 1. Webs are slightly different. To make this a food web, there have to be more connections between the different components, ideally in more than one direction.

The simplified food web in Figure 7 shows that the ultimate energy source is, as with everything on Earth, the sun. The algae, which are a type of phytoplankton (literally meaning “drifting plant”), use photosynthesis to convert the sun’s energy along with the carbon dioxide dissolved in the water to make the bodies of the algae themselves. These algae become food for any herbivores (plant eaters) patrolling the upper levels of the sea. In fact, algae are the primary source of almost all food in the deep seas that the cod and other demersal fish occupy[xii]. The herbivores are eaten by carnivores, which in turn are eaten by bigger (or more ferocious) carnivores; these carnivores are more likely to be fish that occupy the deeper parts of the ocean because algae do not grow where there is no light. When the carnivores (or herbivores, for that matter) die, their bodies are consumed by a plethora of scavengers at all levels, right down to the very floor of the ocean, where scavenging is the lifestyle of choice. But even those scavengers are not free of danger, for carnivores are also partial to a tasty bottom dweller or two. If the amount of sunlight, and thus algae, going into the web reduces, the total food energy in the web reduces, and the total volume of creatures in that web also reduces.




Simple Oceanic Food Web

Figure 7 : Simple oceanic food web showing four trophic levels. Arrows indicate the direction of the energy (food) supply (Source : Author’s image)

Unlike the loop, there is no point at which I can say, “and then it repeats”, because any one of a number of processes could take place next: they are a real pain to predict without some very special analytical skills. This is another reason why scientists like webs. Both webs and loops play a vital part in working out what will happen to biological (or ecological), atmospheric and other systems when environmental conditions change. I purposefully wrote “when”, rather than “if”, because environmental conditions are changing all the time; and many of those changes are of our making.


A Moment Of Reflection

In September 2007 it became possible for the first time in living memory to travel by boat from the southern tip of Greenland[xiii], across the sea north of Canada and then all the way along the north coasts of Russia and Scandinavia, before finally meeting your starting point again. All of this without an icebreaker. For climatologists and anyone who has concern for the future habitation of this planet, this is a frightening occurrence. For oil and shipping companies, as well as governments wishing to impress their power on other nations, it’s open season:

In an exercise in sabre-rattling, the Canadian government has ordered two new military bases to be set up in the Arctic region and commissioned six new patrol ships. But the US is equally adamant that the passage remain free to all comers.

Angry exchanges [in 1985] prompted a 1988 cooperation deal which is now under threat. Russia, Denmark and Norway are separately involved in the scramble to exploit the Arctic's mineral riches.[xiv]

It doesn’t take a genius to realise that every disaster is seen as a commercial opportunity by someone in the world – but it is truly breathtaking to watch the clawing and biting taking place amongst national governments, some of whom pretend to be interested in protecting the planet, in order to gain commercial advantage over each other. This scramble for material wealth (basically a high level form of “beat your neighbour”) both puts the lie to governments’ claims to be cooperative, and also makes it very clear that the strongest motivation of all in the industrial world is the acquisition of wealth. Why people are so strongly motivated by wealth is something that I will explore in detail later on.

You may have spotted a feedback loop in this. If money is driving climate change, by virtue of the greenhouse gases being produced by commercial activity, and climate change is causing more commercial “opportunities” to open up, then clearly this loop will continue to get stronger and stronger until something snaps – such as the planet no longer being able to support human beings in any great number. Alternatively something or someone may decide to drive a stake through that absurd cycle before it gets too late to stop the feedback, and it is taken out of our hands.

Albedo is something I mentioned a few pages back. I often make the mistake of wearing a particular t-shirt I like on sunny days; it is grey, but with thousands of flecks of black, and those black flecks absorb solar energy (solar radiation) very effectively, leaving me hot and bothered. The difference between black and white is simply that black absorbs every wavelength of visible light (if it is truly black it also absorbs infra-red radiation, which makes things particularly hot) and white reflects every wavelength. Blue coloured objects only reflect blue light and absorb everything else, green objects reflect green light, and so on. The more solar radiation absorbed by an object, the more energy is being forced into it, causing it to heat up. Albedo is a measure of how much radiation is reflected by something: the higher the number, the more reflective it is.

The melting snow in Aspen reveals a darker surface than the snow itself. Fresh snow has an albedo of 0.8 to 0.9 – it reflects eighty to ninety percent of the radiation. Green grass has an albedo of 0.25, and soil has an albedo of about 0.2. In other words, the melting of snow increases the amount of energy taken into the ground by a factor of four. Now, compare this to what is happening in the Arctic Ocean. Bare ice, which is typically what floats on water, reflects sixty to seventy percent of the solar radiation falling on it, whereas open sea may reflect almost nothing, depending on the angle of the sun. This huge difference in absorption can make the difference between the temperature of the sea being below freezing – so the ice doesn’t melt – or above freezing. Once the sea gets above freezing point, that heat energy spreads out with the movement of the ocean currents, melting more and more ice, which in turn causes the sea to heat up. This is a dramatic positive feedback loop and it is happening right now.[xv]

The effect of this on marine life is complex, but not really surprising. Water held at close to freezing point, can absorb about 14 milligrams of oxygen per litre, whereas at 20°C it can only hold about 9 milligrams of oxygen in the same volume[xvi]. The high levels of oxygen in cold polar waters compared to warm tropical waters affect the ability of the water to sustain life, but it is not easy to find out what difference this makes in practice. One study involving squid found a plausible relationship between the temperature of the sea surface and the number of squid in a shoal[xvii], some studies find that higher temperatures reduce the amount of food available to predators, but other studies say that the warmer the sea, the higher the biomass. The issue seems to be that there are very complex relationships between different species of marine life at different depths of the ocean, and across different geographical areas; and when you start looking at the more complex food webs then some of these relationships break down, so it’s sometimes safer not to make any assumptions at all.

This type of problem infects all studies of complex systems, and makes it very easy for sceptics to attack a bit here and a bit there while ignoring the overall picture. Greenhouse gas emissions continue to increase; their levels in the atmosphere inexorably rise, while global temperatures continue to creep up; and yet, the denials continue. Denial keeps fear at bay. Denial keeps the wheels of industry turning. Denial keeps rich people rich and powerful people, powerful. I will explain this in Part Three.

A classic example of this selective, convenient denial occurred following the release of a paper by the eminent NASA climatologist James Hansen. The paper explained that USA temperatures between 2000 and 2007 had been overstated by 0.15°C because a necessary adjustment in the climate models had not been applied[xviii]. Bearing in mind that the global picture was untouched by this adjustment, the reaction by the climate change sceptics was over the top, to say the least:

As to the stuff about the hottest years . . . Well, whaddya know! Turns out that’s wrong, too. Figures from NASA’s Goddard Institute for Space Studies (GISS) now show the hottest year since 1880 was 1934. Nineteen-ninety-eight dropped to second, while the third hottest year was way back in 1921. Indeed, four of the 10 hottest years were in the 1930s, while only three were in the past decade.[xix]

Excuse me for being picky, but this only affected the USA temperature record, which puts the commentator on rather rocky ground to start with. As for the record temperatures, the US Climatic Data Centre says: “The last eight 5-year periods [up to 2007], were the warmest 5-year periods (pentads) in the last 113 years of national records, illustrating the anomalous warmth of the last decade. The 9th warmest pentad was in the 1930s (1930-34)”[xx]. Six of the ten warmest years on record in the USA occurred in the last ten years.  To add insult to injury (for the sceptics, that is), every one of the ten warmest years globally have occurred since 1995. Now, let’s get back to the bigger picture.


The Bigger Picture

Part of this picture is that cod grow tremendously fast at higher temperatures[xxi]. At 14°C the growth of cod larvae is up to five times quicker than at 4°C. The problem with any fast growing animal is that it requires lots of food, and a baby growing five times as fast as normal requires at least five times the normal amount of food. In a sea with unlimited food then that isn’t much of a problem, but in a sea where the amount of food is also being impacted by the increase in temperature that is a huge problem; especially when that baby is near the top of the food chain. If a baby’s metabolism is fast but it can’t get the food it needs then it will die.

Another part of the picture, and one mentioned a while ago, is that oxygen can cause a “squeeze” if there is not enough to match the metabolism of an animal[xxii]. The amount of oxygen required by an animal relates directly to the speed and efficiency of its natural processes – breathing, digestion, growth etc. – so if the amount of oxygen available is not sufficient for that animal’s metabolism then its metabolism will have to slow down or the animal cannot survive. Just like when you reach the top of a steep hill and you have to stop for air, if you keep running or walking without a break then you will eventually collapse. Recent NASA data shows at least a 4°C increase in the temperature of some Arctic waters compared to the 20th century average[xxiii]. If we use the figures from a couple of pages back, this means that the amount of oxygen the ocean can dissolve has dropped by ten percent across significant parts of the ocean.

The final part of the picture is that the amount of phytoplankton, the primary source of food for the oceans, is being badly affected by oceanic heating. This is nothing to do with the increased “acidity” of the oceans caused by growing levels of carbon dioxide being drawn into the sea, which in turn causes the shells of zooplankton (tiny floating animals) to dissolve; instead, the warming of the ocean surface means that cold water is not descending as rapidly as it needs to in order to refresh the levels of nutrients close to the surface. Cold water is heavier than warm water, so warm water will always reach the surface eventually; but if the air above the water is warmer than the water itself, then the surface of the water is not cooled down, mixing cannot take place, and nutrients essential to the survival of phytoplankton stay where they are – out of the reach of the plankton. The impact of this is far-reaching[xxiv], and is bound to affect both the amount of prey available to cod, and the ability of the cod to catch their prey in the first place.

If you add this all together then you get a picture of a fish that is being, or will soon be, adversely affected by climate change: enforced faster growth causing starvation, reduced oxygen impacting the normal functions of the fish, and finally a simple lack of food. In an age where we are fishing the oceans to exhaustion because of the perceived need for high levels of cheap animal protein, this additional volley of blows could be the last straw. When the cod are gone what will be left to replace it? Haddock, mackerel, tuna, swordfish – at what point do we decide to stop pulling tonnes of protein out of the oceans and let the natural processes get on with the job of repairing themselves?

[Continue to Chapter 6]


[i] “'Nemo' mania poses threat to clownfish”, The Independent, (accessed 28 January, 2008)

[ii] “From Ocean To Aquarium : The global trade in marine ornamental species”, UNEP / WCMC, 2003.

[iii] Vaclav Smil, “Worldwide transformation of diets, burdens of meat production and

opportunities for novel food proteins”, Enzyme and Microbial Technology (30), 2002.

[iv] Fisheries Research Services, (accessed 29 January, 2008)

[v] Personal communications (January, 2008). The name has been changed; there is a great deal of sensitivity amongst fisherman over these issues – they are often loath to talk to anyone who may give the fishing industry a bad name.

[vi] “The State of World Fisheries and Aquaculture – 2006”, FAO, (accessed 2 February, 2008)

[vii] Garrett Hardin, “The Tragedy Of The Commons”, Science (162), 1968. The original wording is: “The individual benefits as an individual from his ability to deny the truth even though society as a whole, of which he is a part, suffers.” I’m sure he would appreciate the sentiment.

[viii] Mark Kurlansky, “Cod”, 1997, Vintage.

[ix] UN FAO, “World aquaculture production of fish, crustaceans, molluscs, etc., by principal producers in 2005”, (accessed 22 February, 2007)

[x] Rosamond L. Naylor et al, “Effects of Aquaculture on World Fish Supplies”, US EPA, (accessed 22 February, 2008)

[xi] The IPCC report says: “The observed widespread warming of the atmosphere and ocean, together with ice mass loss, support the conclusion that it is extremely unlikely that global climate change of the past 50 years can be explained without external forcing, and very likely that it is not due to known natural causes alone.” IPCC 4th Assessment Report, Working Group 1, “Summary for Policymakers”, IPCC, 2007.

[xii] John Gordon, “Deep Sea Demersal Fisheries”, Joint Nature Conservation Committee,

[xiii] More properly known as Kalaallit Nunaat, in Greenlandic, but for convenience I will refer to it as Greenland.

[xiv] “Ice melts opening up Northwest Passage”, Daily Telegraph, (accessed 1 February, 2008)

[xv] A simple but striking presentation of this can be found at (accessed 1 February, 2008), which shows both feedback loops and a web of connections between the different components.

[xvi] Government of British Columbia, Ministry of Environment, “Ambient Water Quality Criteria for Dissolved Oxygen”, (accessed 4 February, 2008)

[xvii] Laurence Challier et al, “Environmental and stock effects on recruitment variability in the English Channel squid Loligo forbesi”, Aquat. Living Resour. (18), 2005.

[xviii] NASA GISS, “GISS Surface Temperature Analysis: August 2007 Update and Effects”, (accessed 23 February, 2008)

[xix] Michael Fumento, “James Hansen’s Hacks”, (accessed 5 February, 2008)

[xx] “2007 Annual Climate Review U.S. Summary”, US NCDC, (accessed 5 February, 2008)

[xxi] E. Otterlei et al, “Temperature dependent otolith growth of larval and early juvenile

Atlantic cod (Gadus morhua)”, ICES Journal of Marine Science (59), 2002.

[xxii] David O. Conover, “Effects of Climate Change on Fisheries”, (accessed 5 February, 2008)

[xxiii] NASA GISS, “GISS Surface Temperature Analysis: Global Temperature Trends: 2007 Summation”, (accessed 4 February, 2008). The average is officially between 1951 and 1980, but this works out to be very close to the average for the entire century.

[xxiv] Michael J. Behrenfeld et al, “Climate-driven trends in contemporary ocean productivity”, Nature (444), 2006.


A Matter Of Scale by Keith Farnish is licensed under a Creative Commons Attribution-Non-Commercial 3.0 Unported License.


[Top Of Page]