Rising Seas

Martin Ince

• Publisher: Routledge
• Year: 2013
• eBook ISBN: 9781134044610
• Edition: 1
• Topic: Economics
• Subtopic: Sustainable Development
• Index: Economics

Recent and dramatic flooding in places as far apart as Bangladesh and North Wales are example of what could become commonplace if sea levels rise. Most scientists are predicting a rise of about one metre and this book, based on research carried out for the Commonwealth governments, describes in simple terms what in. likely to happen as a result and where the worst effects will be.

Martin Ince, a well-known scientific journalist, deals with the accuracy of our knowledge and the possible errors in assessment. He considers the different kinds of damage that higher seas could cause, inundation, increased salination, coral damage, increased flood and surge damage and so on. Brief case studies are included covering the UK, the Maldives, North America, Bangladesh, Guyana, Kiribati, The Netherlands, Italy, Egypt and Australasia. The book ends with an examination of the scientific and technical developments which could make the problems easier to deal with and, above all, set. out the policies on which governments must agree. Originally published in 1990

1 The warmer, wetter world

Storms send the sea into houses and across fields in Britain; high tides make hundreds of thousands homeless in Bangladesh; low-lying islands in the Pacific no longer produce food as rising salt water attacks their crops; the huge delta of the Mississippi spreads into areas that used to be dry land. All over the world, coasts seem to be slipping beneath the waves.

This book will look at the silent disaster of the rising sea, which threatens thousands of square kilometres of land around the world, the livelihoods and ways of life of millions of people, and the future of unique species and biological habitats. It will look especially closely at the likelihood that the seas are rising because the Earth is getting warmer, a process which may be due to the effects of human activity on its atmosphere. But the seas have always risen and fallen, as a pleasurable day out at the coast will show.

Take a walk along the shore in the Highlands of Scotland, or in many other parts of the world, and you may find that you can stroll on the beach with no risk of getting wet. Under your feet, as you walk along tens of metres above sea level, you will find sand, complete with seashells. This is a raised beach, a relic of times, thousands of years ago, when the sea was far higher than it is today. These raised beaches, in common with other evidence from many parts of the world, speak eloquently of the fact that the relationship between land and sea has been constant only in its variability throughout the history of the Earth. Many coastlines exhibit raised beaches, while in other parts of the world underwater investigations have revealed shorelines, river channels and other land features far below today’s low-water mark. In some cases, there is strong evidence that major changes in sea level have occurred over very short periods of time.

But the fear today is that the activities of the human race are leading to changes in the Earth which will mean sea level changes far faster than those which nature manages without artificial assistance. This book aims to look at the possibility of such changes, consider how they might affect different parts of the world and the people who live there, and assess the new policies and new knowledge which will be necessary to deal with the problem.

I shall argue throughout that the real issue about the rising sea is not how high up the beach the high tide comes. Instead, the subject contains subtle and difficult arguments about science, money, morality, people and politics. In any case, the sea level issue is not a free-standing policy problem. Instead it is a part of a more general issue: the extent to which gases emitted to the atmosphere by industry and other human activities will raise the Earth’s temperature by trapping incoming energy from the Sun which would otherwise be radiated back into space.

This is the greenhouse effect, and the gases that cause it are the greenhouse gases. As we shall see, countless uncertainties are associated with the greenhouse effect. To these is added a further layer of questions about just how the greenhouse effect might, as it unfolds, be translated into rising sea levels. The link between the two involves a complex chain of cause and effect involving oceanography, glaciology, meteorology and other messy subjects which we shall encounter shortly.

But of more significance than these scientific uncertainties, doubled and redoubled by the unknowns in our current knowledge of the way the Earth works, is a series of even more intractable issues about the way the world works. Scientific knowledge leaves large areas of doubt about how much sea levels are going to rise, but a rise would not occur in a uniform manner throughout the world. Different types of coastline would react differently to an equivalent rise in the sea, which might leave a rocky shore unaffected and cause severe damage to a sandy one, or flood a populous estuary area while leaving an area of cliffs all but unaffected.

More importantly, the rising sea will affect different areas of the world differently in terms of its impact on the people who live there. It will do so simply because people themselves vary, and most particularly they vary economically and in how they live. For example, London is protected from flooding by the Thames Barrier, installed because of a growing flood hazard caused mainly by the gradual subsidence of South-East England. Many Third World areas face far more immediate and dangerous flood hazards, but they do so without a Thames Barrier because they have neither the wealth nor the political influence to buy one. If sea levels rise, the Barrier will be of even more use to London, and places without one will be even more disadvantaged economically.

It follows that the key factor determining how the rising sea will affect any given individual is that individual’s existing social and economic circumstances. If you are poor already, rising sea levels will make you poorer by removing your livelihood and the place where you live. If you are living somewhere that is prone to pollution, flooding or other forms of disaster, rising sea levels will tend to make your problems worse. For example, the rising sea will flood your land more often, poison your land and drinking water with salt, and damage the drainage and flood defence system which defend you from the sea.

In richer countries the same problems will arise in some of the same ways, but their effects on the societies of the developed world will be quite different. In the extreme case of the complete destruction of livelihoods by the rising sea, the nationally and personally wealthy states and individuals of the developed world would be far better prepared to cope by re-creating the lives of the affected individuals elsewhere. In the intermediate case – damage short of complete destruction – developed world countries would be able to spend far more on sea defences, new drainage and sewage systems and other measures used to counter rising seas.

In addition, it so happens that the countries of the world whose existence is most fundamentally threatened by the rising sea are all in the Third World, with the exception of the Netherlands, a country whose existence is entirely dependent upon sea defences. Across the Pacific and into the Indian Ocean lie a clutch of nations like the Maldives (one of the Commonwealth nations whose concern with the rising sea has prompted a variety of initiatives on the subject, including this book), whose land is all close to sea level and which risks flooding, total immersion or other forms of damage as the sea rises.

This book’s analysis will maintain that in an important way, rising sea levels do not alter the basic facts about the world. However, the rising sea is not a zero-sum game like commodity speculation, in which some participants get richer at the expense of others. Like many other environmental problems, the rising sea will impoverish virtually everyone it touches, but will do so without creating a separate social or economic group who win out as the other loses. Large areas of developed world countries like the USA and Britain are threatened by the rising sea. On the southern and eastern seaboards of the USA, rising sea levels – not associated with the greenhouse effect – are already causing widespread destruction. Sea level rise has the power to make rich areas poor, put physical stresses on areas accustomed to immense physical advantages, and create immense demands for sea defences and other investments which are likely to be costly even for developed nations.

The problem for anyone interested in sea level rise is to understand just how it might occur, on what scale and how fast. The third part of this question is especially important to the inhabitants of land areas threatened by sea level rise, since a change which would be disastrous if it happened overnight or over a year might be bearable if some years were available to find out about the problem, think about its solution, implement it – and, of course, pay for it.

The starting point for understanding these problems is the greenhouse effect itself. Since the early 1980s, when the Office of Technology Assessment of the US Congress published a report pointing out that the sheer amounts of carbon dioxide being pumped into the Earth’s atmosphere were bound to have some effect on the climate, shelves and, indeed, whole libraries have been filled with material on the greenhouse effect. The subject has been widened out with the discovery of new ways in which the effect might take place and by the application of sophisticated scientific modelling processes to the problem, along with a whole gamut of work on the Sun’s radiation and the way in which it interacts with the Earth.

But first things first. What is all this talk of greenhouses? And why do they have an effect named after them?

Greenhouses allow plants which would have trouble growing out of doors to be grown under cover instead. To some extent they do this by cutting out the winds and frosts which would affect plants out of doors, but the greenhouse effect proper comes into play when the greenhouse receives radiation – mainly visible sunlight – from the Sun. Most of the radiation emitted by the Sun is light, at wavelengths visible to our eyes – or, to put it the other way round, we have evolved to see things in the type of light which is most available. When this radiation reaches the greenhouse, it goes through the glass and warms the inside.

The radiation emitted by any object is characteristic of its temperature – any physicist looking at the amount of energy emitted by the Sun at different wavelengths could tell you that its surface is at a temperature of about 5600°C. Naturally even the most efficient greenhouse is not this warm, so the energy which the things in it emit has a quite different set of wavelengths. The tomato plants, the greenhouse floor and everything else inside it emit energy of longer wavelengths, invisible to human observers. And just as visible light will not travel through brick, the radiation given off by objects at room temperature will not travel through glass, the main substance of which greenhouses are made. The heat builds up inside the greenhouse instead, keeping everything in it warm. Hey presto – the greenhouse effect!

In the case of the Earth and its greenhouse effect, no sheets of glass are necessary. Instead, the contents of the atmosphere act to hold in energy which would otherwise be lost to outer space after being reflected from the Earth’s surface. The gases in question do not do this by forming cloudy layers which reflect heat back to the Earth – a perfectly clear sky can be as efficient a greenhouse layer as an overcast one. This is because all the greenhouse action takes place at wavelengths which our eyes cannot see, in the infra-red, energy transmitted at slightly longer wavelengths than visible red light. The chemical bonds which hold atoms together into molecules often involve energy in these wavelengths, which means that the many molecules can absorb infra-red energy just as glass does.

The greenhouse effect is not a completely artificial one. The main greenhouse gas in the atmosphere is carbon dioxide, which is present naturally – although human activities are now adding hugely to the amounts of it and the size of the greenhouse effect it causes. The greenhouse effect is seen in its fullest form on the planet Venus, whose surface temperature is some 400°C higher than it would be if the planet had no atmosphere. The dense Venusian atmosphere consists of 95 per cent carbon dioxide, although other gases present in small amounts are also responsible for a significant part of the greenhouse effect there.

The same applies on Earth, where gases which are present in far smaller amounts than carbon dioxide, but have a stronger greenhouse effect per molecule, are also important. They include methane (the “natural gas” used by domestic consumers and businesses), ozone (a form of oxygen where every molecule has three atoms instead of the usual two), chlorofluorocarbons (complex organic compounds involving carbon and the halogen elements chlorine and fluorine), and several oxides of nitrogen. Many of these gases are a cause of environmental concern even if their role in the greenhouse effect is disregarded. Ozone is a poison, nitrogen oxides are thought to be carcinogenic, and the chlorofluorocarbons are responsible for the destruction of the ozone in the upper atmosphere which prevents harmful ultraviolet light from the Sun reaching the Earth.

However, working out exactly how large a greenhouse effect these gases might cause is a complex task involving a large number of uncertainties. First there is the most significant of the greenhouse gases, carbon dioxide. Carbon dioxide is not a massively powerful greenhouse gas, molecule for molecule; as we shall see, plenty of less common gases are proportionally far more significant in the greenhouse effect. But carbon dioxide dominates the greenhouse effect because it is much the most common of the greenhouse gases. More problematic still is the fact that this odourless, colourless and completely non-toxic gas is the characteristic emission of twentieth-century industrial society.

Carbon dioxide is emitted every time a piece of wood is burnt in a stove in the Third World – or, for that matter, every time an animal breathes out. Comparatively small quantities such as these can easily be absorbed by plant life – everything from trees to plankton in the ocean – which takes in carbon dioxide and emits oxygen. The Earth’s atmosphere as we know it – consisting mostly of nitrogen plus just over 20 per cent oxygen – was initially produced, several hundred million years ago, by just this mechanism: when plants appeared which could turn carbon dioxide, which had previously been present in the atmosphere in large amounts, into oxygen as a by-product of the process known as photosynthesis, in which solar energy and a catalyst called chlorophyll are used to build plant material.

However, the real problem is that natural emissions of carbon dioxide have been added to in recent decades by large amounts of unnatural carbon dioxide produced by burning fossil fuels – oil, coal and natural gas. Although some other forms of energy, like nuclear power, are in use in modern industrial societies, most of the developed world today runs on fossil fuels. There are disagreements about just how large the world’s fossil fuel reserves are and how long they might last, but the basics are not in doubt. On present form, fossil fuels which have been built up over hundreds of millions of years are set to be consumed over a period of a few centuries, a disparity with which the carbon-dioxide-absorbing machinery of the Earth will probably be unable to cope.

In addition, there is another characteristic activity of the late twentieth century which adds greenhouse carbon dioxide to the Earth’s atmosphere – the cutting down of forests, especially large areas of tropical forest, for use as agricultural land. Even if farmland replaces the forest completely – which can often fail to happen – the plants on that farmland have nothing like the forest’s carbon-dioxide-absorbing capacity. If the trees are burnt to clear the land, turning their carbon into carbon dioxide, so much the worse.

The sheer amounts of carbon dioxide emitted to the atmosphere by human activities are startling. Generally accepted estimates presented in London at a 1989 conference on climate change held for the benefit of Prime Minister Margaret Thatcher and other senior ministers in the UK government put annual emiss ions at 5.6–5.7 billion (thousand million) tonnes for 1988. For the previous decade the average annual total was some 5.3 billion tonnes. This is the total due to fossil fuel burning and cement manufacture, in which limestone is incinerated, with carbon dioxide being emitted as a by-product. In addition, more carbon dioxide is emitted by non-commercial fuel burning, mostly the burning of fuelwood in the Third World, which is counted only patchily by the statistics. Land use changes – mostly the removal of forests – account for another 1.5 billion tonnes a year on average for the decade to 1988. This figure is open to doubt and probably varies widely from year to year, but – at over a quarter of the figure for the total emissions from fossil fuel burning – is still extraordinary.

This amount of carbon dioxide adds up to about 7 billion tonnes a year. If it were all collected together at sea level and a temperature of zero centigrade, it would add up to 5600 cubic kilometres of gas, a block 18 kilometres long on one side. Even in a volume as massive as that of the Earth’s atmosphere itself, this amount of pollution makes itself felt.

The amount of fossil fuel burnt has been steadily increasing since the late nineteenth century, and fortunately for all concerned, there are also accurate records of the effect of the resulting carbon dioxide emission on the Earth’s atmosphere. One consistent set of records on the matter comes from an observatory on Mauna Loa, a volcano on Hawaii in the mid-Pacific. Here data on carbon dioxide concentrations in the atmosphere have been collected on a consistent basis since 1958, in a site so remote from industrial activity that we...

Table of contents

• Cover
• Title page
• Copyright
• Contents
• Acknowledgements
• Foreword
• 1 The warmer, wetter world
• 2 How the rising seas hurt
• 3 Third World damage
• 4 Rising seas and the rich
• 5 Small states and rising seas
• 6 Facing the rising seas
• 7 Living with the rising seas
• Bibliography
• Index