Sustainable development means using resources wisely without damaging the environment and keeping in mind the need of future generations. Indiscriminate use of resources leads to: A rapid depletion of resources An economic divide in the society, Environmental and ecological problems like pollution, land degradation, global warming and ozone layer depletion. The first Earth Summit was held in Rio de Janeiro in Brazil in June where leaders from over countries signed the Declaration on Global Climatic Change and Biological Diversity, approved the global forest principles and adopted Agenda Agenda 21 aims to prevent environmental damage and fight poverty and diseases through global cooperation.
It also aims to encourage local governments to form their own Agenda 21 based on local issues. The resources in a country are not distributed uniformly across all its regions. That discovery does not, however, affect the amounts of the metal present on Earth. Metals are often used to manufacture parts of buildings and machinery.
To some degree, the metals can be recovered after these uses and recycled back into the economy, effectively extending the lifespan of their reserves. However, due to the growth and increasing industrialization of the economy, the demand for metals is accelerating.
Because recycling cannot keep up with the increasing demands for metals, large additional quantities must be mined from their known reserves in the environment. For valuable metals, such as gold and platinum, there is a high efficiency of recycling, but it is much less so for iron and other less-costly metals. Fossil fuels are the other major category of non-renewable resources.
They are mostly combusted to provide energy for transportation and heating, which converts their organic compounds into carbon dioxide and water, which are released into the environment. Some of that CO 2 and H 2 O may be absorbed by plants and other photosynthetic organisms and be converted back into organic materials, a process that might be interpreted as being a kind of recycling.
However, the rate at which this happens is insignificantly small compared with the release of the CO 2 and H 2 O by the combustion of fossil fuels, so these materials should be viewed as being as non-renewable as metals are. A more minor use of fossil fuels is to manufacture various kinds of plastics. These synthetic materials can be recycled after initial uses, which does help to extend the lifespan of the reserves of fossil fuels. Nevertheless, because the dominant use of fossil fuels is as sources of energy, they essentially flow through an industrial economy, with little new recycling.
Image Non-renewable resources can only be mined. This is a view of the Etaki open-pit diamond mine in the Northwest Territories. Three open pits can be seen as a cluster, plus another at the top-left of the image, along with an extensive tailings-disposal area and other infrastructure.
Renewable resources are capable of regenerating after harvesting, so potentially their stocks can be utilized forever. Most renewable resources are biological, although some are non-biological. Biological Renewable Resources Renewable resources that are biological in nature bio-resources include the following:.
Renewable resources, such as timber and fish, are capable of regenerating after they are harvested. Provided they are not over-harvested or managed inappropriately, renewable resources can be harvested in a sustainable fashion.
This photo shows a load of timber that was harvested on Vancouver Island. Source: B. Non-Biological Renewable Resources The following are renewable resources that are non-biological:. Many renewable resources can be managed to increase their rates of recruitment and productivity and to decrease mortality. In the following section we explain how management practices can be used to increase the productivity of biological resources.
Although a renewable resource can regenerate after harvesting, it can also be badly degraded by excessive use or by inappropriate management. These practices can damage the ability to regenerate and may ultimately cause a collapse of the stock. As such, it becomes depleted by excessive use. For this reason, ecologists commonly use the qualified term: potentially renewable resources.
Global Focus Easter Island was first discovered by wandering Polynesians around the 9th century. The only foods these people brought with them were chicken and sweet potato the climate is too temperate for tropical foods known to the Polynesians, such as breadfruit, coconut, taro, and yam.
Initially, the Easter Islanders could hunt abundant fish and porpoises in the rich coastal waters of their island, and they could catch wild Polynesian rats, a species they had introduced. By the 16th century, the Easter Islanders had developed a flourishing society, with a population as large as 15, Because of food surpluses, they had time to engage in a cultural activity that involved carving huge slabs of stone into human-faced monoliths, which they erected on great bases of stone at special places along the coast.
Human-faced moai, which are large monoliths carved of volcanic stone on Easter Island. However, Easter Island was soon deforested by the aggressive cutting of trees for fuel, to construct buildings and fishing boats, and for use as rollers.
Once the forest resource was gone, several key enterprises of the islanders collapsed. Stone monoliths could no longer be moved, sturdy homes could not be built, and fishing and porpoise hunting became impossible. It also became difficult to cook food and keep warm because the only other fuel available was the sparse biomass of shrubs and herbaceous plants.
In other words, the deforestation of their island caused the economy of this Polynesian society to collapse. The cultural and economic disintegrations were so great that when Europeans first arrived at Easter Island in , the inhabitants could not remember why the stone monoliths had been erected. These people were living in squalid conditions in caves and reed huts, were engaged in warfare among rival clans, and were cannibals, possibly to supplement the meagre food available on their treeless island.
An obvious lesson of Easter Island is that even primitive societies are capable of over-exploiting the vital resources needed for subsistence. Undoubtedly, the Easter Islanders were keenly aware of their precarious circumstances — especially the limited resources available to sustain their society on a small and isolated island.
As these vital resources became obviously diminished, the people likely discussed the need to conserve their economic base. However, any such deliberations came to naught, and there was an irreversible collapse of the economy and culture of these people.
Any of these natural resources can be rapidly depleted by excessive use. There was no alternate, resource-rich refuge to which the Easter Islanders could escape from their self-inflicted catastrophe. Likewise, as far as we know, there is no alternative to planet Earth. Potentially at least, populations of animals and plants, and their assemblages known as communities and ecosystems such as a tract of forest , can be harvested in a sustainable manner — that is, without depleting the size of the resource or its capability to renewal.
Essentially, this is due to the fact that, within limits, bio-resources are able to regenerate after some of their biomass is harvested. As long as the rate of harvesting does not exceed that of regeneration, a bio-resource can be used in a sustainable way. Ultimately, the upper limits of the productivity of an individual organism is limited by genetically determined factors that influence its fecundity, longevity, and growth rate.
To reach that potential limit of productivity, an organism must experience optimal environmental conditions. In a collective sense, genetic factors also set a ceiling on the potential productivity of populations or organisms, as well as communities and larger ecosystems. However, in the real world it is typical that environmental conditions are not optimal, and so the actual or realized recruitment, growth, and maturation of individuals and biomass are less than their potential amounts.
As a result, it is possible to increase the size of a harvest by the use of management practices that enhance the productivity of bio-resources. When these practices are used in a coordinated way, they are called a management system.
In general, the various management practices are designed to alleviate environmental constraints on productivity. This is done by mitigating factors that may be preventing some recruitment, or are causing mortality, or are constraining the rate of productivity. In any case, however, the expression of many genetic factors is influenced by environmental conditions, various of which restrict productivity Figure Therefore, in the real world of ecosystems, the actual productivity of bio-resources is less than their potential.
Figure Factors Affecting the Yield of a Biological Resource. The biomass and productivity of a bio-resource are determined by the recruitment of individuals into the population, their growth rates, and their mortality through either harvesting or natural means. These factors are affected by both genetically determined and environmental influences. Often, environmental and biological factors can be managed to increase the productivity and size of the stock of a bio-resource.
Source: Modified from Begon et al. If resource managers understand the nature of constraints on the productivity of bio-resources, and can devise ways to reduce those influences, then the yield of harvested products can be increased.
In any truly sustainable system of resource management, those increases in yield must be obtained without degrading the capability of the resource for renewal they cannot be obtained by over-harvesting the resource or by degrading environmental conditions.
The most important practices that are used to increase the productivity of bio-resources are described below. Note, however, that while these are commonly used methods of increasing the productivity of bio-resources, all management practices cause some degree of ecological damage, as is examined in later chapters. In all species, there is some degree of genetically based influence on biological attributes of individuals such as fecundity, longevity, and productivity.
This is the basis by which all domesticated species used in agriculture were developed, and cultural selection is still an important way in which crop varieties are produced see also Chapter In addition, since the s, new methods have been developed for transferring genetic information from one species to another — these have been used to create so-called transgenic crops see Environmental Issues 6.
The rate of recruitment of new individuals into an exploited population can be increased in various ways. Some commonly used methods are described below. As noted previously, the productivity of all plants and animals is constrained by environmental influences, which include inorganic factors such as nutrient availability and temperature and biological ones such as competition and disease. Often, management practices can be used to manipulate environmental conditions to reduce their limitation on growth rate, allowing an increased harvestable yield.
Sometimes a management system is used, involving a variety of practices applied in a coordinated manner. Some examples follow. Mortality of juveniles and adults can seriously affect the sizes of plant and animal stocks. However, by thinning out the stock, mortality also influences the intensity of competition and that can increase the growth rate of survivors.
Natural mortality can be caused by predation, disease, or disturbance, while harvesting mortality is associated with use by humans. Resource depletion occurs when the total rate of mortality natural plus harvesting exceeds the regenerative capability of the stock. Fishing Technologies. Methods of catching fish vary enormously in their efficiency and in the associated harvesting mortality.
Source: Freedman Potentially, all management options including selective breeding, enhancement of growth and recruitment rates, and management of mortality rate can result in larger yields of bio-resources. However, the factors that influence the size and productivity of stocks of renewable resources are imperfectly understood. Consequently, the management systems advocated by resource scientists are also imperfect. Despite this caveat about uncertainty, enough is usually known about ecological factors affecting bio-resources to design harvesting and management systems that will not degrade the capability for renewal.
At the very least, precautionary levels of harvesting that are small enough to avoid over-exploiting the resource can be predicted, even though the harvest might be smaller than the potential maximum sustainable yield. It is not necessary that harvests of natural resources are as large as are potentially attainable. If resource managers cannot predict an accurate MSY, then it is ecologically prudent to harvest at a rate known to be smaller than the MSY, but that is clearly sustainable.
Of course, such strategies result in smaller harvests and less short-term profit. These are, however, more than offset by the longer-term economic and ecological benefits of adopting prudent strategies of resource use. In forestry, for example, the export of raw logs might be prohibited, while local manufacturing of value-added products such as lumber, furniture, and violins would be encouraged.
Similarly, a regional fishing industry might focus on the production and export of higher-valued products, such as prepared foods, rather than unprocessed fish.
These kinds of integrations of resource harvesting and manufacturing can optimize the regional economic benefits of resource-based industries, while allowing smaller, sustainable harvests of the resource to take place. Regrettably, non-sustainable rates of harvesting have been common in the real world of open, poorly regulated, bio-resource exploitation. These facts become clear from the examples of resource degradation described in this chapter and also in Chapters 14 and Many potentially renewable resources have been used by humans in an unsustainable manner.
Either these resources were excessively harvested a condition known as over-harvesting or over-exploitation , or their post-harvest regeneration was inappropriately managed. Either of these can result in depletion or exhaustion of the resource by so-called mining a term more usually applied to a non-renewable resource. There are many examples of the non-sustainable use of potentially renewable resources. A few species have even been made extinct by excessive hunting, such as the dodo, passenger pigeon, and great auk the latter two occurred in Canada; see Chapter In other cases, seemingly abundant species were rendered endangered by over-harvesting, including American ginseng, Eskimo curlew, northern fur seal, plains bison, right whale, trumpeter swan, and other once-common species Chapter In fact, there are remarkably few examples of economically valuable, potentially renewable resources that have not been severely depleted at one time or another through excessive use or inappropriate management.
Additional examples of the mining of potentially renewable resources include the following:. Not all cases of the mining of potentially renewable resources have occurred in modern times. Examples that are prehistoric are described in Global Focus These well-known cases demonstrate that even relatively unsophisticated human societies with primitive technologies have caused enormous damage to their crucial resource base.
In some cases, an early depletion of potentially renewable resources was followed by efforts of conservation or improved management, which subsequently restored the depleted stocks but not ones that had been made extinct.
For example, regulating the hunting of white-tailed and mule deer has allowed those species to remain abundant in regions where habitat is suitable. Comparable successes have been achieved with other once-depleted animals, such as certain sportfish, ducks, and geese. Examples of these kinds of conservation successes are described as case studies in Chapter Overall, however, there is more bad news than good about future stocks and regeneration of many potentially renewable resources.
Although some renewables are being used in a manner that is supportive of their future availability, many are not. If this situation does not change for the better in the near future, there will be grim consequences for the human economy, and also for biodiversity and natural ecosystems.
Prehistoric Extinctions Paleontologists have found clear evidence of prehistoric mass extinctions of animal species, apparently caused by over-hunting by stone-age humans Martin, , ; Diamond, , Although the extinctions occurred at different times and places, all of them coincided with the discovery and colonization of a landmass that was previously uninhabited by people.
These mass extinctions represent cases of non-sustainable harvesting of wild-animal populations, which were potentially renewable bio-resources for the neolithic hunters.
In North America, a wave of extinctions began about thousand years ago, soon after people colonized the continent by migrating across a land bridge from Siberia. The land bridge existed because sea level was much lower than today, as a result of so much water being tied up in glacial ice.
Within a relatively short time, at least 56 species of large mammals weighing more than 44 kg , 21 smaller mammals, and several large birds had become extinct. The extinctions included 10 species of horses genus Equus , the giant ground sloth Gryptotherium listai , four kinds of camels family Camelidae , two buffalo genus Bison , a cow genus Bos , the saiga antelope Saiga tatarica , and four kinds of elephants including the mastodon Mammut americanum and mammoth Mammuthus primigenius.
Predators and scavengers that depended on these large herbivores also became extinct, including the sabre-toothed tiger Smilodon fatalis , the American lion Panthera leo atrox , and a huge scavenging bird Terratornis merriami. The best collection of fossil bones of many of the extinct animals has been excavated from the La Brea tar pits in southern California. However, bones of many species are widespread and some have been found in various places in Canada.
As colonizing people spread from North America into Central America, and then into South America, extinctions of many other vulnerable species also occurred there. An artistic impression of a wooly mammoth left and an American mastodon right. Similar events of mass extinction have occurred elsewhere, also coinciding with the colonization of places by stone-age hunters. In New Guinea and Australia, waves of extinction occurred about thousand years ago, following the discoveries of those islands by Melanesians migrating south from Asia.
These extinctions involved the losses of many large marsupials, flightless birds, and tortoises. In New Zealand, an extinction wave occurred less than 1, years ago, following the discovery of those islands by Polynesians.
This swept away numerous large, flightless birds, including a kg, 3-m giant moa Dinornis maximus , 26 other species of moa, a goose Cnemiornis calcitrans , a swan Cygnus sumnerensis , a giant coot Fulica chathamensis , a pelican Pelecanus novaezealandiae , an eagle Harpagornis moorei , and fur seals and various large lizards and frogs. The extinctions of the moas progressed as a wave from North Island to South Island over a two-century period following the Polynesian colonization.
Great quantities of bones have been discovered at places where the moas were herded and butchered. Some of the bone deposits were mined by European colonists and used as phosphate fertilizer. The human colonization of Madagascar occurred about 1, years ago. This also resulted in many extinctions, including the loss of species of huge elephant birds, 14 lemurs, 2 giant tortoises, and other large animals.
All are believed to have resulted from over-hunting by newly colonizing people. Clearly, the unsustainable use of bio-resources, resulting in irretrievable losses of species important to people, is not only a modern phenomenon.
In cases where only a particular species is being harvested, over-exploitation generally involves an excessive harvesting rate, occurring without sufficient attention to regeneration. Under such conditions, the stocks are quickly mined, and they collapse to economic or biological extinction.
Because younger individuals are often relatively fast growing, the productivity of the resource is not necessarily smaller than that of the initial old-growth stock, although the total biomass may be less.
However, if this kind of resource degradation is taken too far, the population may collapse in both productivity and biomass. The collapse may be caused by inadequate recruitment into the harvested population because the fecundity of younger individuals is not sufficient to offset the harvesting mortality.
Patterns of resource degradation are more complicated in the case of mixed-species resources, which are often over-exploited in a sequential manner. At first, only certain species in the virgin mixed-species resource may be considered desirable from the economic perspective.
In addition, some individual organisms may be very large, especially in the case of old-growth resources. For instance, old-growth forest of coastal British Columbia is typically dominated by large individuals of valuable tree species, which are coexisting with many smaller individuals see Chapter Many pre-exploitation communities of fish, whales, and other species are also typically dominated by large individuals of desirable species.
The exploitation of a mixed-species resource usually involves a sequential harvest of commodities with progressively smaller economic value measured as value per individual, as well as per unit of biomass and of harvested area. Initially, the largest individuals of the most valuable species are harvested selectively and are rapidly depleted. In an old-growth forest, for example, the largest logs of the most desirable species have the highest value per unit of biomass — they can be used to manufacture large-dimension lumber of precious species or costly veneer products.
The intention of post-harvesting management is not to re-create another old-growth forest, because this would take too much time and would also involve an extended period of relatively low productivity see Chapter Instead, the site is typically converted into a second-growth forest. Next, smaller individuals of the most desired species might be harvested selectively, along with the largest individuals of secondarily desired species.
In a forest, the economic products might be smaller-dimension lumber. If management of the regenerating stand is intended to produce timber for manufacturing into lumber, the subsequent harvests would be on a relatively long rotation, say years, depending on the growing conditions.
However, area-harvesting methods might then be used to harvest all individuals of all species for manufacturing into bulk commodities. In the case of forestry, trees might be clear-cut for the production of small lumber, pulp, industrial fuel, charcoal, or domestic fuelwood. Subsequent harvests for such purposes would be on a short rotation, perhaps years.
Sometimes the area-harvesting system is followed by management that regenerates a productive resource, although it has a different character from the original, natural ecosystem.
In forestry, for example, natural mixed-species forest might be converted into a single-species plantation or perhaps into an agricultural ecosystem see Chapter Intensive harvesting, sequential or otherwise, can also lead to a collapse of biological productivity and therefore to a huge loss of resource value. For instance, clear-cut forests sometimes regenerate into shrub-dominated ecosystems that resist the establishment of tree seedlings.
This severe resource degradation may require expensive management to restore another economically useful forest. Ecologically rich old-growth forest in tropical countries is being rapidly cleared to provide agricultural land. The conversion results in destruction of the forest the mining of a potentially renewable resource , often to develop agricultural land that may not be productive for very long.
In this case, the rice paddies may be cultivated for many years, but the hillsides have been badly degraded by temporary agricultural use. This scene is from Sumatra, Indonesia. To function over the longer term, an economy depends on a sustained input of natural resources.
Given this vital context, it would appear to be economically self-destructive to degrade renewable resources by over-harvesting them or by inappropriate management. Nevertheless, this maladaptive behaviour has occurred frequently through human history.
In fact, most uses of potentially renewable resources have been decidedly non-sustainable, and have caused stocks to become depleted. The most important reasons for this foolish behaviour are outlined below. Within an economic context that involves free access to common-property resources these are owned by all of society , the above factors inevitably lead to the over-harvesting of potentially renewable resources.
Individual, self-interested farmers believed that they would gain additional economic benefits by having as many of their own sheep as possible grazing the pasture. This led to an excessive aggregate use of the pasture, which damaged the forage resource. Many nations are experiencing crises because of diminishing stocks of natural resources and the associated ecological damage caused by disturbances, pollution, and loss of biodiversity.
Remarkably, many of these countries have not yet attempted to deal effectively with the resource depletion. With few exceptions, the design and implementation of intelligent strategies for using natural resources has so far proven to be beyond the capability of modern political and economic systems.
Nevertheless, people are definitely capable of designing and implementing systems that would conserve natural resources and the healthy ecosystems that are required to sustain economies.
The solutions to resource-related predicaments require an integration of scientific knowledge and social change, along with the adoption of ecologically based economic policies that pursue true sustainability. Such solutions are far preferable to unfettered economic growth based on the depletion of natural resources. In Detail Over the longer term, the liquidation of potentially renewable resources is clearly a losing strategy for society and for future generations.
Therefore, influential people often advocate and pursue this tactic. Luinenberg, O. To an economist, growth and development are different phenomena.
Economic growth is a feature of an economy that is increasing in size over time. It is associated with increases in both the numbers of people and their per-capita use of resources. Particularly in developed countries, economic growth is typically achieved by a rapid consumption of natural resources. Non-renewable resources, such as metals and fossil fuels, are consumed in especially large quantities in a growing economy.
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