FEATURES Environmental changes in perspective: The global response to challenges Through Earthwatch and the Agenda 21 action plan, the IAEA is contributing to global efforts addressing environmental problems by Pier Roberto we approach the end of the second millen- a "cosmic clock". (See figure, page 4.) This Danesi and Hadj nium, a series of major problems seems to clock has a dial compressing the entire history of Slimane Cherif threaten the world's rapidly expanding popula- the planet into a 24-hour day. The birth of the tion: the consequences of global warming, the planet is set at 00:00 hours and the present is set hole in the ozone layer, pollution of the Earth's at 24:00 hours. On this scale the appearance of oceans, fresh waters, soil and atmosphere, the homo sapiens occurs only at about two seconds declining biodiversity, and the degradation of before present. The rapidity of the induced land and soil quality. Concerns appear to be changes is even more striking when one consid- justified, at least as long as the world's main ers that our ancestors were hunter-gatherers until development goals continue to be the economic 10,000 years ago when, with the domestication levels of its wealthiest nations and their high of plants and animals, agriculture was invented. consumption and waste production patterns. It is then only at about 0.2 seconds before present How can we better assess and appreciate the in the "cosmic clock", when human communi- impact that anthropogenic environmental ties started to become controllers of the global changes have made to our planet and the magni- ecosystem rather than an integral part of it. (See tude of population growth? table, page 4.) It may first be worthwhile to place them into As agriculture developed and more of the an appropriate time perspective relative to the Earth's surface was modified, food surpluses overall age of the Earth. Our planet was formed permitted the establishment of permanent settle- about 4.5 billion years ago. It took about one ments. With the introduction of metal-working billion years before the first bacterial organisms technology, more efficient tools for environ- appeared and about 2.5 billion years before the mental manipulation were introduced. Gradually atmosphere contained enough oxygen to eventu- agriculture and metal smelting expanded at the ally permit the formation of the first modern cells expense of forests. Cleared land was used for (eucaryotic cells). Nevertheless, their develop- cultivation and forest wood for construction and ment required another one billion years. The to generate charcoal for larger scale metal smelt- development of life over the following 1.5 bil- ing. However these processes had moderate or lion years progressively brought the environ- negligible impacts on the global environment ment of our planet to the state it was known to until the beginning of the Industrial Revolution the first homo sapiens of about 100,000 years (about 250 years ago or just 0.004 seconds be- ago. In practice, it took the entire age of the fore present on the "cosmic clock"). Earth, namely about 4.5 billion years, to develop As coal replaced wood for fuel, triggering the a natural environment that stayed practically un- rapid rise of fossil fuel consumption and the affected by anthropogenic effects until about beginning of industrialization in northwest 10,000 years ago. Europe, the magnitude of environmental The "Cosmic Clock". The time of major changes started to increase dramatically. Inten- events which characterized the evolution of the sive agriculture and expanding industrial activi- Earth can be represented on what has been called ties — the creators of food security and wealth which permitted the human race to expand — would also become threats to the Earth's life Mr. Danesi is Director of the IAEA's Laboratories at Seibers- support system. However, considering that in dorf and Vienna. Mr. Cherif is Special Assistant to the IAEA 1830 the world population was about one billion, Director General in the area of technical co-operation, nuclear power and safety, and nuclear applications. it is not surprising that it took more than another IAEA BULLETIN, 2/1996 FEATURES century before the world started to become tary problems when human and industrial waste Rice fields in Indonesia. aware of the environmental changes that indus- is disposed of without appropriate and costly (Credit: Curt Camemark, trial development and agriculture were causing. measures. At the same time, rural areas tend to World Bank) The size of the problem can be fully appreci- become environmentally damaged as migration ated when one considers the rapidity of the world to towns encourages the abandonment of envi- population's growth after the Industrial Revolu- ronmentally sound agricultural practices, such as tion. (See graph, next page.) The population of irrigation, terracing, and crop rotation. The push the world was about 200 million at the time the towards the introduction of cash crops creates Greek philosopher Aristotle was born (384 BC). additional environmental problems. It took about 2000 years (1650) to reach 500 However, it must be emphasized that the million. Over the next 150 years (by 1830) the influence of population growth on environ- population had doubled to one billion and it took mental changes is rather complex. It involves, only 100 years (1930) to reach two billion. among others, complex correlations among in- Now, only 65 years later, we are approaching come levels, production, and consumption pat- the six billion value. By the year 2100 we will be terns. For example, although the industrialized 12 billion. This population growth is particularly countries contain 23% of the world population, alarming because it will almost entirely occur in it has been estimated that they are presently pro- the developing countries, which already host ducing more than 75% of the world's waste. The 77% of the world population but share only 15% main reason is that these countries, with their of the world income. high living standards, produce and consume Moreover, actual trends indicate that soon large quantities of energy to manufacture goods the world population will mainly concentrate and deliver the services their population expects. (about 50%) in big megacities, having between This is inevitably associated with the generation 15 and 25 million inhabitants. The concentration of considerable waste. of people in big cities has strong negative effects Although the gap in income between the rich on both urban and rural environments. Cities and poor countries of the world may not decrease generate huge amounts of solid, liquid, and gase- in the future, it is expected that the income levels ous wastes, causing water and air pollution prob- of the poor countries will slowly rise between lems. Moreover, they can create enormous sani- now and the year 2025. A minor income in- IAEA BULLETIN, 2/1996 FEATURES Some approximate dates important for the The "Cosmic Clock": 4.5 billion years of the planet Earth evolution of life, humans and culture compressed into one day Years Time of the Homo Sapiens before event before appears at 23:59:58 present present on the 24-hour cosmic clock Plants invade Birth of land Planet Earth Life First Vertebrates 500 million 2 hrs and 30 min Multicellular Ancient First Reptiles 300 million 1 hr and 30 min organisms bedrocks First Mammals 200 million 1 hr First Primates 70 million 20 min First bacterial organisms Humans Earliest Homides 4 million 80 sec Stone tools 2 million 40 sec Homo Sapiens 100 000 2 sec Modern cells Culture Blue-green algae; photosynthesis Invention 10 000 0.2 sec of agriculture First cities and 5 000 0.1 sec writing Scientific Age 500 0.01 sec (Copernicus) Source: Adapted from "Svensk Industrial Age 250 0.004 sec Energifdrsdrjning 1990". Twentieth Century 100 0.002 sec Adapted from A. Hobson, "Education in Global Change", A Planet in our Hands, G. Marx, Editor, Roland Eotvos Physical Society, Budapest (1995). The population explosion 12 billion by the year 2100 AD crease, coupled with a sharp increase of the population, has led to the estimate that by the year 2025 about half of the world's waste (and 85% of the new wastes) will be generated by developing countries. This indicates that it is not simply population growth but population growth combined with living standards that threatens to accelerate environmental degradation. \ 6 billion by the year 2100 AD Signs of environmental changes At this point, a legitimate question might be asked: To what extent has human development al- ready caused environmental changes during the last two thousandths of a second (0.002 sec), which represents the 20th century, on the "cosmic clock'? 2 billion in 1900AD Much has been written on the greenhouse effect caused by the release of carbon dioxide 1 billion in 1800 AD during the burning of fossil fuels and by other gases, and about global wanning and whether it 400 200 0 200 400 600 800 1000120014001600180020002200 already has been detected. Extensive literature B.C. B.C. Year also exists on the causes and consequences of the hole in the ozone layer and other signs of local Source: Adapted from A. Hobson, 'Education in Global Change', from "A Planet in and global environmental changes induced by Our Hands',G. Marx Ed., Roland E6tv6s Physical Society, Budapest, 1995, Page 18. human activities. Unfortunately, precise envi- ronmental indicators are in general still lacking IAEA BULLETIN, 2/1996 FEATURES and in most cases only approximate estimates are available. The signs are in any case rather alarm- Differentregions of the world affected by land degradation ing. A few examples will be sufficient to sense (million hectares) the extent of the global and local problems we are and will be facing in the near future.