Figures

1.1 World population growth and significant technological developments 5 1.2 Schematic diagram of the earth atmosphere system 6 1.3a Schematic diagram of a natural subsystem a lake basin 7 1.3b Schematic diagram of a subsystem of anthropogenic origin a thermal electric 2.1 Spectral distribution of solar and terrestrial radiation 15 2.2 The hydrologic cycle 17 2.3 Energy transfer during the change in state of water 18 2.4 The vertical structure of the atmosphere and its associated temperature...

Further Study Necessary Or

Current global environmental problems are remarkably complex, and, despite an increasingly intensive research effort, they are even now not completely understood. That situation must change, if solutions are to be found. Almost all individuals and organizations studying the problems have indicated that further study is necessary. In the past, that was often seen as a delaying tactic in that it was often easier to suggest further study than to make a positive attack on a problem. Attempts to...

The Atmospheric Gases

The constituents of the atmosphere are collectively referred to as air, although air itself is not a specific gaseous element, rather it is a mixture of individual gases each of which retains its own particular properties. Although traces of atmospheric gases have been detected well out into space, 99 per cent of the mass of the atmosphere lies within 30 km of the earth's surface, and 50 per cent is concentrated in the lowest 5 km. Most of the world's weather develops in these lower layers, but...

Environmental Issues Global Warming In 1975

Source After Houghton et al. (1990) example, the nature and rate of industrial development, the extent to which the earth's forests continue to be destroyed and the success of programmes aimed at reducing the output of CO2. Most studies have based their predictions on several scenarios, one of which is commonly a direct projection of the status quo the IPCC 'business-as-usual' scenario, for example with others based on either increase or decreases in CO2 and combinations of other gases (Bolin...

Water In The Atmosphere

The creation of acid rain would not be possible without water, another of the major natural constituents of the atmosphere. Lists of the principal gases in the atmosphere such as Table 2.1 commonly refer to dry air, but the atmosphere is never completely dry. The proportion of water vapour in the atmosphere, in the humid tropics, may be as much as 4 per cent by volume, and even above the world's driest deserts there is water present, if only in fractional amounts. At any one time, the total...

Atmospheric turbidity

One of the more obvious indications of atmospheric pollution is the presence of solid or liquid particles, called aerosols, dispersed in the air. These aerosols are responsible for phenomena as diverse as the urban smogs that bedevil the world's major cities, and the spectacular sunsets which often follow major volcanic eruptions. The concentration and distribution of particulate matter in the atmosphere is closely linked to climatic conditions. Some local or regional climates encourage high...

The threat to the ozone layer

One of the most important functions of the atmosphere is to provide the surface of the earth with protection from solar radiation. This may seem contradictory at first sight, since solar radiation provides the energy which allows the entire earth atmosphere system to function. As with most essentials, however, there are optimum levels beyond which a normally beneficial input becomes harmful. This is particularly so with the radiation at the ultraviolet end of the spectrum (see Table 6.1). At...

Acid Rain And The Aquatic Environment

The earliest concerns over the impact of acid rain on the environment were expressed by Robert Smith, in England, as long ago as 1852 Park 1987 , but modern interest in the problem dates only from the 1960s. Initial attention concentrated on the impact of acid rain on the aquatic environment, which can be particularly sensitive to even moderate increases in acidity, and it was in the lakes and streams on both sides of the Atlantic that the effects were first apparent. Both LaBastille 1981 and...

Atmospheric Aerosols

In addition to the gaseous components of the atmosphere and the water in its various forms, there are also solid or liquid particles dispersed in the air. These are called aerosols, and include dust, soot, salt crystals, spores, bacteria, viruses and a variety of other microscopic particles. Collectively, they are often regarded as equivalent to air pollution, although many of the materials involved are produced naturally by volcanic activity, forest and grass fires, evaporation, local...

Environmental And Socio Economic Impacts Of Increasing Greenhouse Gases

Given the wide range of possibilities presented in the estimates of future greenhouse gas levels and the associated global warming, it is difficult to predict the environmental and socio-economic effects of such developments. However, using a combination of investigative techniques ranging from laboratory experiments with plants to the creation of computer generated models of the atmosphere and the analysis of past climate anomalies researchers have produced results which provide a general...

Aerosols And Radiation

Atmospheric aerosols comprise a very heterogeneous group of particles, and the mix within the group changes with time and place. Following volcanic activity, for example, the proportion of dust particles in the atmosphere may be particularly high in urban areas, such as Los Angeles, photochemical action on vehicle emissions causes major increases in secondary particulate matter over the oceans, 95 per cent of the aerosols may consist of coarse sea-salt particles. Such variability makes it...

Solutions

Although there may be individuals and groups who for various reasons are willing to continue with the 'do nothing' or 'business-as-usual' approaches to current global environmental problems, they are a minority, and the urgent need to provide solutions is widely accepted. Given the complexity of the problems being addressed, it is not surprising that there is no one approach that satisfies all needs. Most of the options currently being considered involve either adaptation or prevention, and...

To Human Interference

The impact of society on the environment depends not only on the nature of society, but also on the nature of the environment. Although it is common to refer to 'the' environment, there are in fact many environments, and therefore many possible responses to human interference. Individually, these environments vary in scale and complexity, but they are intimately linked, and in combination constitute the whole earth atmosphere system see Figure 1.2 . Like all systems, the earth atmosphere system...

Vapotranspiration

Invisible drought can be dealt with relatively easily by irrigation. In eastern Britain, for example, supplementary moisture has been supplied to sugar beet and potato crops since at least the late 1950s to deal with that problem Balchin 1964 . To establish the existence of a deficit in an area, it is necessary to compare incoming and outgoing moisture totals. The former is normally represented by precipitation and the latter by evaporation from the earth's surface plus transpiration by plants,...

The Physical Chemistry Of The Ozone Layer

Ozone owes its existence to the impact of ultraviolet radiation on oxygen molecules in the stratosphere, with the main production taking place in tropical regions where radiation levels are high Rodriguez 1993 . Oxygen molecules normally consist of two atoms, and in the lower atmosphere they retain that configuration. At the high energy levels associated with ultraviolet radiation in the upper atmosphere, however, these molecules split apart to produce atomic oxygen see Figure 6.1 . Before...

The atmosphere

The atmosphere is a thick blanket of gases, containing suspended liquid and solid particles, which completely envelops the earth, and together with the earth forms an integrated environmental system. As part of this system, it performs several functions which have allowed mankind to survive and develop almost anywhere on the earth's surface. First, it provides and maintains the supply of oxygen required for life itself. Second, it controls the earth's energy budget through such elements as the...

Human Activities And The Atmospheric Environment

Certain elements in the environment remain untamed, uncontrollable and imperfectly understood. Nowhere is this more evident than in the realm of weather and climate. Neither nineteenth nor twentieth century technology could prevent cyclones from devastating the shores of the Bay of Bengal, or hurricanes from laying waste the Caribbean. The Sahelian drought spread uncontrollably even as the first astronauts were landing on the moon. The developed nations, where society's dominance of the...

Desertification

Although often severe, the problems which arise in most areas experiencing seasonal or contingent drought are seen as transitory, disappearing when the rains return. If the rains do not return, the land becomes progressively more arid until, eventually, desert conditions prevail. This is the process of desertification in its simplest form. When considered in this way, desertification is a natural process which has existed for thousands of years, is reversible, and has caused the world's deserts...

Summary

In many parts of the world, low precipitation levels combine with high evapotranspiration rates, to produce an environment characterized by its aridity. Under natural conditions, the ecological elements in such areas are in balance with each other and with the low moisture levels. If these change, there is a wholesale readjustment as the environment attempts to attain balance again. The early inhabitants of these areas also had to respond to the changes, and, as long as their numbers remained...

Info

The nations of the world came together in Rio de Janeiro in June 1992 at the United Nations Conference on Environment and Development UNCED dubbed the Earth Summit to try to reach consensus on the best way to slow down, halt and eventually reverse ongoing environmental deterioration. The Summit represented the culmination of two decades of development in the study of environmental issues, initiated at the United Nations Conference on the Human Environment held in Stockholm in 1972. Stockholm...

Drought famine and desertification

What Causes Drought The Sahel

In recent years, the world's attention has been drawn time and again to the Third World nations of Africa, by the plight of millions of people who are unable to provide themselves with food, water and the other necessities of life. The immediacy of television, with its disturbing images of dull-eyed, pot-bellied, malnourished children, skeletons of cattle in dried-up water courses, and desert sands relentlessly encroaching upon once productive land, raised public awareness to unexpected...

Aerosol Types Production And Distribution

Aerosol Types And Sources

The total global aerosol production is presently estimated to be between 2-3x109 tonnes per annum, and on any given day perhaps as many as 1x107 tonnes of solid particulate matter is suspended in the atmosphere Bach 1979 Cunningham and Saigo 1992 Ahrens 1993 . Under normal circumstances, almost all of the total weight of particulate matter is concentrated in the lower 2 km of the atmosphere in a latitudinal zone between 30 N and 60 N Fennelly 1981 . The mean residence time for aerosols in the...

The changing greenhouse effect

Palaeoenvironmental evidence suggests that the greenhouse effect fluctuated quite considerably in the past. In the Quaternary era, for example, it was less intense during glacial periods than during the interglacials Bach 1976 Pisias and Imbrie 1986 . Present concern is with its increasing intensity and the associated global warming. The rising concentration of atmospheric CO2 is usually identified as the main culprit, although it is not the most powerful of the greenhouse gases. It is the most...

Nitrogen oxides

Nitrogen oxides NOx are very effective destroyers of ozone see Figure 6.4 . Nitric oxide NO is most important, being responsible for 5070 per cent of the natural destruction of stratospheric ozone Hammond and Maugh 1974 . It is produced in the stratosphere by the oxidation of nitrous oxide N2O , which has been formed at the earth's surface by the action of denitrifying bacteria on nitrites and nitrates. It may also be produced in smaller quantities by the action of cosmic rays on atmospheric...

The contribution of other greenhouse gases

Most predictions of future changes in the intensity of the greenhouse effect are based solely on changes in the CO2 content of the atmosphere. Their accuracy is therefore questionable, since CO2 is not the only greenhouse gas, nor is it the most powerful. Methane CH4 , nitrous oxide N2O and the CFCs are the most important of the other greenhouse gases. Tropospheric ozone O3 is also capable of enhancing the greenhouse effect, but its present concentrations are very variable in both time and...

Alternative points of view and the problems of GCMs

The global warming scenario, in which a doubling of atmospheric CO2 would cause a temperature increase of 1.3-4.5 C, is widely accepted. This consensus has evolved from the results of many experiments with theoretical climate models which indicate the considerable potential for change in the earth atmosphere system as concentrations of atmospheric greenhouse gases increase. Even the most sophisticated General Circulation Models GCMs cannot represent the working of the atmosphere exactly,...

Drought And Famine In Africa

Weather Conditions Associated With Itcz

Although seasonal drought is experienced in all of the world's sub-tropical areas, in recent years the greatest effects have been felt in sub-Saharan Africa, including the region known as the Sahel where drought is much more persistent than elsewhere on the continent Nicholson 1989 . The Sahel proper is that part of western Africa lying to the south of the Sahara Desert and north of the tropical rainforest. It comprises six nations, stretching from Senegal, Mauretania and Mali in the west,...

Volcanic activity weather and climate

Many of the major volcanic eruptions in historical times have been followed by short-term variations in climate which lasted only as long as the dust veil associated with the eruption persisted. The most celebrated event of this type was the cooling which followed the eruption of Tambora in 1815. It produced in 1816 'the year without a summer', remembered in Europe and North America for its summer snowstorms and unseasonable frosts. Its net effect on world temperature was a reduction of the...

Spawning of fathead minnow prevented Recruitment failure of lake trout Lower limit for Atlantic salmon hatching

Aluminium also kills a variety of invertebrates, but the progressive concentration of the metal through food chains and food webs ensures that higher level organisms such as fish are particularly vulnerable, and it is possible that fish kills previously attributed to high acidity were, in fact, the result of aluminium poisoning Park 1987 . The mobilization of heavy metals by leaching may also help to reduce fish populations indirectly by killing the insects and microscopic aquatic...

The Creation Of The Greenhouse Effect

The greenhouse effect is brought about by the ability of the atmosphere to be selective in its response to different types of radiation. The atmosphere readily transmits solar radiation which is mainly short-wave energy from the ultraviolet end of the energy spectrum allowing it to pass through unaltered to heat the earth's surface. The energy absorbed by the earth is reradiated into the atmosphere, but this terrestrial radiation is long-wave infrared, and instead of being transmitted it is...

Oceanic And Atmospheric Circulation Patterns

Oceanic And Atmospheric Circulation

More than half of the solar radiation reaching the earth's surface is absorbed by the oceans, where it is stored and redistributed, before being released back into the atmosphere. Ocean and atmosphere are quite intimately linked. The prevailing winds in the atmospheric circulation, for example, drive water across the ocean surface at speeds of less than 5 km per hour, in the form of broad, relatively shallow drifts. In some cases, they carry warm water polewards, in others, they carry cooler...

Chlorofluorocarbons halons and the ozone layer

Effect Ozone

If there was some doubt about the impact of SST exhaust emissions on the ozone layer, the effects of some other chemicals seemed less uncertain. Among these, the chlorofluorocarbon CFC group and related bromofluorocarbons or halons have been identified as potentially the most dangerous see Table 6.2 . The CFCs, sometimes referred to by their trade name, Freon, came to prominence as a result of lifestyle changes which have occurred since the 1930s. They are used in refrigeration and air...

Atmospheric carbon dioxide and temperature change

Although present concern with global warming centres on rising concentrations of atmospheric CO2, concentrations of that gas have varied considerably in the past. Analysis of air bubbles trapped in polar ice indicates that the lowest levels of atmospheric CO2 occurred during the Quaternary glaciations Delmas et al. 1980 . At that time, the atmosphere contained only 180 to 200 parts per million by volume ppmv of CO2, although there is some evidence that levels fluctuated by as much as 60 ppmv in...

Solutions To The Problem Of Acid Rain

Problems Acid Rain

Although the cause and effect relationship between emissions of SO2 and NOX and acid rain damage is not universally accepted, most of the solutions proposed for the problem involve the disruption of that relationship. The basic approach is deceptively simple. In theory, a reduction in the emission rate of acid forming gases is all that is required to slow down and eventually stop the damage being caused by the acidification of the environment. Translating that concept into reality has proved...

Drought On The Great Plains

Topeka Tropical Rainforest Climate Graph

Since all of the nations stricken by drought in sub-Saharan Africa are under-developed, it might be considered that lack of economic and technological development contributed to the problem. To some extent it did, but it is also quite clear that economic and technological advancement is no guarantee against drought. The net effects may be lessened, but the environmental processes act in essentially the same way, whatever the stage of development. This is well illustrated in the problems faced...

Acid Rain And Geology

The impact of acid rain on the environment depends not only on the level of acidity in the rain, but also on the nature of the environment itself. Areas underlain by granitic or quartzitic bedrock, for example, are particularly susceptible to damage, since the soils and water are already acidic, and lack the ability to 'buffer' or neutralize additional acidity from the precipitation. Acid levels therefore rise, the environmental balance is disturbed, and serious ecological damage is the...

The Antarctic ozone hole

Total ozone levels have been measured at the Halley Bay base of the British Antarctic Survey for more than thirty years beginning in the late 1950s. Seasonal fluctuations were observed for most of that time, and included a thinning of the ozone above the Antarctic during the southern spring, which was considered part of the normal variability of the atmosphere Schoeberl and Krueger 1986 . This regular minimum in the total ozone level began to intensify in the early 1980s, however see Figure 6.6...

Agricultural fertilizers nitrous oxide and the ozone layer

When concern for the ozone layer was at its height, compounds other than CFCs were identified as potentially harmful. These included nitrous oxide, carbon tetrachloride and methyl chloroform. Methyl bromide has recently been added to the group. It is used extensively as a fumigant to kill pests in the fruit and vegetable industry, and may be responsible for as much as 10 per cent of existing ozone depletion. However, its actual impact is still a matter of dispute MacKenzie 1992 . Nitrous oxide...

The Geography Of Acid Rain

Acid Rain Norway

Total global emissions of the SO2 and NOX, the main ingredients of acid rain, are difficult to estimate. Fossil fuel combustion alone produces about 91 million tonnes annually Hameed and Dignon 1992 and other activities, both natural and anthropogenic, add to that. The main sources are to be found in the industrialized areas of the northern hemisphere. Northeastern North America, Britain and western Europe have received most attention see Figure 4.3 , but eastern Europe and the republics of the...

Climatological effects

The climatological importance of the ozone layer lies in its contribution to the earth's energy budget see Figure 6.8 . It has a direct influence on the temperature of the stratosphere through its ability to absorb incoming radiation. Indirectly, this also has an impact on the troposphere. The absorption of short-wave radiation in the stratosphere reduces the amount reaching the lower atmosphere, but the effect of this is limited to some extent by the emission of part of the absorbed short-wave...

The Vertical Structure Of The Atmosphere

Vertical Structure Stratosphere

Although its gaseous constituents are quite evenly mixed, the atmosphere is not physically uniform throughout. Variations in such elements as temperature and air pressure provide form and structure in what would otherwise be an amorphous medium. The commonly accepted delineation of the atmosphere into a series of layers, for example, is temperature based see Figure 2.4 . The lowest layer is the troposphere. It ranges in thickness from about 8 km at the poles to 16 km at the equator, mainly as a...

Acid Rain And The Built Environment

Present concern over acid rain is concentrated mainly on its effect on the natural environment, but acid rain also contributes to deterioration in the built environment. Naturally acid rain has always been involved in the weathering of rocks at the earth's surface. It destroys the integrity of the rock by breaking down the mineral constituents and carrying some of them off in solution. All rocks are affected to some extent, but chalk, limestone and marble are particularly susceptible to this...

Naturally Occurring Ozone Destroying Catalysts

Naturally Occurring Ozone

Natural catalysts have probably always been part of the atmospheric system, and many such as hydrogen, nitrogen and chlorine oxides are similar to those now being added to the atmosphere by human activities. The main difference is in production and accumulation. The natural catalysts tend to be produced in smaller quantities and remain in the atmosphere for a Figure 6.1 Schematic representation of the formation of stratospheric ozone Figure 6.1 Schematic representation of the formation of...

The carbon cycle and the greenhouse effect

Greenhouse Effects Schematic

Three of the principal greenhouse gases CO2, methane CH4 and the CFCs contain carbon, one of the most common elements in the environment, and one which plays a major role in the greenhouse effect. It is present in all organic substances, and is a constituent of a great variety of compounds, ranging from relatively simple gases to very complex derivatives of petroleum hydrocarbons. The carbon in the environment is mobile, readily changing its affiliation with other elements in response to...

Cooling Or Warming

In the mid-1970s, increasing atmospheric turbidity associated with human activity was considered to be one of the mechanisms capable of inducing global cooling Calder 1974 Ponte 1976 . The processes involved seemed plausible and logical, at least in qualitative terms. The introduction of pollutants into the atmosphere, at a rate greater than they could be removed by natural processes, would allow the progressive build up of aerosols until sufficient quantities had accumulated to cause a rise in...

Nuclear Winter

Agricultural Effects Nuclear War

The Kuwait oil field fires provided the atmosphere with probably the greatest amount of anthropogenically generated aerosols ever produced by a single event, and to a number of observers they shared similarities with the major fires expected to follow a nuclear war Pearce 1991 a . Urban fires, for example, with ready access to smoke producing wood, paper, plastics and fossil fuels would produce similar combustion products. The fires likely to be ignited by nuclear explosions were estimated to...

Chlorine oxides

The extent to which naturally produced chlorine monoxide CIO contributes to the destruction of the ozone layer is not clear. The most abundant natural chlorine compound is hydrochloric acid HC1 . Although it is present in large quantities in the lower atmosphere, HCl is highly reactive and soluble in water, and Crutzen 1974 considered that it was unlikely to diffuse into the stratosphere in sufficient quantity to have a major effect on the ozone layer. The addition of large amounts of chlorine...

Bentshoe Lake

Waterways, until the spring melt occurs. At that time they are flushed into the system in concentrations many times higher than normal. Measurements in some Ontario lakes have shown a reduction in pH values of more than two units in a matter of a few days although decreases of the order of one pH unit are more common Ontario Ministry of the Environment 1980 Jeffries 1990 . This augmented level of acidity may last for several weeks, and, unfortunately, it often coincides with the beginnings of...

The Montreal Protocol

In September 1987, thirty-one countries, meeting under the auspices of the United Nations Environment Program in Montreal, signed an agreement to protect the earth's ozone layer. The Montreal Protocol was the culmination of a series of events which had been initiated two years earlier at the Vienna Convention for the Protection of the Ozone Layer. Twenty nations signed the Vienna Convention in September 1985, promising international cooperation in research, monitoring and the exchange of...

The Human Contribution To Atmospheric Turbidity

The volume of particulate matter produced by human activities cannot match the quantities emitted naturally see Figure 5.7 . Estimates of the human contribution to total global particulate production vary from as low as 10 per cent Bach 1979 to more than 15 per cent Lockwood 1979 with values tending to vary according to the size-fractions included in the estimate. Human activities may provide as much as 22 per cent of the particulate matter finer than 5 pm, for example Peterson and Junge 1971 ....

The Kuwait Oil Fires

In the final stages of the Gulf War in February 1991 between 500 and 600 oil wells were set alight by the retreating Iraqi army. These wells continued to burn for several months, kept alight by oil and gas brought to the surface under pressure from the underlying oil fields. During that time they added massive amounts of smoke, sulphur dioxide, carbon dioxide, unburned hydrocarbons and oxides of nitrogen to the atmosphere. Most of these products were confined to the lower half of the...

The Nature And Development Of Acid Rain

Scale Showing Acid Rain

Acid rain is normally considered to be a byproduct of modern atmospheric pollution. Even in a pure, uncontaminated world, however, it is likely that the rainfall would be acidic. The absorption of carbon dioxide by atmospheric water produces weak carbonic acid, and nitric acid may be created during thunderstorms, which provide sufficient energy for the synthesis of oxides of nitrogen NOX from atmospheric oxygen and nitrogen. During volcanic eruptions or forest fires, sulphur dioxide SO2 is...

Supersonic transports and the ozone layer

The planning and development of a new generation of transport aircraft was well under way in North America, Europe and the USSR by the early 1970s. These were the supersonic transports or SSTs , designed to fly higher and faster than conventional, subsonic civil airliners, and undoubtedly a major technological achievement. It became clear, however, that they could lead to serious environmental problems, if ever produced in large numbers. Initial concerns included elevated noise levels at...

Volcanic Eruptions And Atmospheric Turbidity

The large volumes of particulate matter thrown into the atmosphere during periods of volcanic activity are gradually carried away from their sources to be redistributed by the wind and pressure patterns of the atmospheric circulation. Dust ejected during the explosive eruption of Krakatoa, in 1883, encircled the earth in about two weeks following the original eruption Austin 1983 , and within 8 to 12 weeks had spread sufficiently to increase atmospheric turbidity between 35 N and 35 S Lamb 1970...

The Economics And Politics Of Acid Rain

Balance Trade Sulfur Dioxide 1980

Government participation in pollution abatement is not a new phenomenon, but, in recent years, particularly following the Clean Air legislation of the 1960s and 1970s, the role of government has intensified, and pollution problems have become increasingly a focus for political intervention. Thus, when acid rain emerged as a major environmental problem, it was inevitable that any solution would involve considerable governmental and political activity. Given the magnitude of the problem it also...

Nuclear war and the ozone layer

When a modern thermonuclear device is exploded in the atmosphere, so much energy is released, so rapidly, that the normally inert atmospheric nitrogen combines with oxygen to produce quantities of oxides of nitrogen NOx . The rapid heating of the air also sets up strong convection currents which carry the gases and other debris into the stratosphere, and it is there that most of the NOx is deposited. Since natural NOx is known to destroy ozone, it is only to be expected that the...

Acid Rain And The Terrestrial Environment

Acid Rain Impacted Forests Ontario

Terrestrial ecosystems take much longer to show the effects of acid rain than aquatic ecosystems. As a result, the nature and magnitude of the impact of acid precipitation on the terrestrial environment has been recognized only recently. As early as 1965, however, air pollution was known to be killing oak and pine trees on Leo Tolstoy's historic estate at Yosnaya Polyana Goldman 1971 . There is growing evidence that those areas in which the waterbodies have already succumbed to acidification...

Current State Of The Issues Atmospheric turbidity

Environment Problems

One of the first environmental issues to be considered in a global context was the rising level of atmospheric turbidity, which was the centre of concern in the mid-1970s. It linked air pollution with the cooling of the earth. Cooling had been taking place since the 1940s, and some writers saw the world descending into a new Ice Age. It was clear a decade later that the cooling had reversed, and atmospheric turbidity began to receive less attention. Evidence also began to appear indicating that...