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Sustainability and development Proponents of sustainable development have been trying to reconcile the urgent needs of effective environmental protection and conservation of resources with economic development. While the concept has been politically successful at bringing sustainability into the mainstream, both in developed and developing countries, it remains controversial.[29]

The skeptics have pointed out that infinite economic growth is impossible on a finite planet, and that Earth’s limits also define the limits of all material-based activities. Some contend that the term itself is an oxymoron, creating the impression that humans can "have their cake and eat it too."[30] In reality, sustainable development has tended to mean nothing more than ecologically more sensitive growth — a slightly reformed status quo. Rebuttals involve, on one hand, the claims of expanding carrying capacity through human ingenuity, and on the other hand, a different conception of development.[31]

Some of the advocates of sustainable development have argued it is best understood as qualitative improvement. In that case, development means “better” rather than “more” and an emphasis on quality of life, rather than material living standards. They call for better, not faster, lives and for a focus on values, not things. These advocates of a new paradigm urge a movement away from the dogma that the only wealth is material wealth, with the resulting development being recognized formally by an improvement in the quality of life indicators.[32]

Environmental sustainability is the process of making sure current processes of interaction with the environment are pursued with the idea of keeping the environment as pristine as naturally possible.

An "unsustainable situation" occurs when natural capital (the sum total of nature's resources) is used up faster than it can be replenished. Sustainability requires that human activity only uses nature's resources at a rate at which they can be replenished naturally. Inherently the concept of sustainable development is intertwined with the concept of carrying capacity. Theoretically, the long-term result of environmental degradation is the inability to sustain human life. Such degradation on a global scale could imply extinction for humanity.

Consumption of renewable resources State of environment Sustainability More than nature's ability to replenish Environmental degradation Not sustainable Equal to nature's ability to replenish Environmental equilibrium Steady-state economy Less than nature's ability to replenish Environmental renewal Sustainable development

[edit] Human impact on the biosphere Land for nature - Catalonia Land for humans - ChicagoThe Millennium Ecosystem Assessment provides the most comprehensive current synthesis of the state of the Earth’s ecosystems. Natural systems (often referred to as ecosystem services) are humanity's life-support system, providing the necessary conditions for humans to flourish. Over the last 50 years the rapidly escalating and potentially critical nature of human global impact on the biodiversity of these ecosystem services has become the source of major biological concern. [33] [26]

At a fundamental level human impact on the Earth is being manifest through changes in the global biogeochemical cycles of chemicals that are critical to life, most notably those of water, oxygen, carbon, nitrogen and phosphorus.

There is now clear scientific evidence that human activity is having a significant effect on all of these cycles.[34]

GLOBAL GEOCHEMICAL CYCLES CRITICAL FOR LIFE Nitrogen Cycle Water Cycle Carbon Cycle Oxygen Cycle

Phosphorus cycle

[edit] Protecting the biosphere There are two major ways of reducing human impact on the planet. The first is to monitor and respond to direct human impacts on the oceans and freshwater systems, the land and atmosphere (see direct impacts below). This approach is based on information gained from environmental science and conservation biology.[33] However, this is management at the end of a long series of causal factors (known to ecologists as drivers) that are initiated by human consumption, our demand for food, energy, materials and water [35] (see indirect impacts below). It is the assessment of consumer demand for these basic resources that is now a major study area for sustainability science which monitors resource use through the chain of human consumption starting with the effects of lifestyle choices and individual and collective spending patterns, through to the resources used in producing specific goods and services, the demands of economic sectors - and even national economies. This is pre-emptive demand management of causes, rather than a reactive response to the effects of this demand.Sustainability governance can be implemented at all levels of human and biological organization, from local to global.

[edit] Direct global environmental impacts

[edit] Atmosphere Main topic: climate change

Use of the atmosphere Top of the atmosphereThe most obvious human impact on the atmosphere is the air pollution in our cities. The pollutants include toxic chemicals such as nitrogen oxides, sulphur oxides, volatile organic compounds and particulate matter that produce photochemical smog and acid rain. Anthropogenic particulates such as sulphate aerosols in the atmosphere reduce the direct irradiance of the Earth's surface. Known as global dimming the decrease is estimated at about 4% between 1960 and 1990 although the trend has subsequently reversed. Global dimming may have disturbed the global water cycle by reducing evaporation and rainfall in some areas: it also creates a cooling effect and this may have partially masked the effect of greenhouse gases on global warming.[36] [37] However, it is now human-induced climate change and the carbon cycle that have become a major focus of scientific research because of the potential for catastrophic effects on both biodiversity and human communities (see Energy below).

[edit] Oceans Thorsmork, IcelandMain topics: overfishing, ocean acidification, marine pollution.

Saltwater fishOceans and their circulation patterns have a critical effect on climate and the food supply for both humans and other organisms. Major environmental impacts occur in the more habitable regions of the oceans – the estuaries, coastline and bays. Because of their vastness oceans act as a dumping ground for human waste. Trends of concern include: ocean warming, reef bleaching and sea level rise, all due to climate change together with the possibility for a sudden alteration of present-day ocean currents which could drastically alter the climate in some regions of the globe; over-fishing (beyond sustainable levels); and ocean acidification due to dissolved carbon dioxide.[4]

Remedial strategies include: more careful waste management, statutory control of overfishing, reduction of fossil fuel emissions, and restoration of coastal and other marine habitat.

[edit] Land Main articles: Land use, land-use change and forestry, land cover, urbanization, deforestation.

Land use change is fundamental to the operations of the biosphere. This includes alteration to biogeochemical cycles, effects of agriculture, proportions of forest and woodland, grassland and pasture.[4]

[edit] Forests Main articles: forestry, deforestation, carbon sequestration, climate change.

Historically about 47% of the world’s forests have been lost to human use. Present-day forests occupy about a quarter of the world’s ice-free land with about half occurring in the tropics [38] In temperate and boreal regions forest area is gradually increasing (with the exception of Siberia), but deforestation in the tropics is of major concern.

Beech Forest - Grib Skov, DenmarkForests can moderate the local climate and the global water cycle through their light reflectance (albedo) and evapotranspiration. They also conserve biodiversity, protect water quality, preserve soil and soil quality, provide fuel and pharmaceuticals, and purify the air. These free ecosystem services have no market value and so forest conservation has little appeal when compared with the economic benefits of logging and clearance which, through soil degradation and organic decomposition returns carbon dioxide to the atmosphere. The United Nations Food and Agriculture Organisation (FAO) has estimated that about 90% of the carbon stored in land vegetation is locked up in trees and that they sequester about 50% more carbon than is present in the atmosphere. Changes in land use currently contribute about 20% of total global carbon emissions (in heavily logged Indonesia and Brazil it is the greatest source of emissions).[39] Climate change can be mitigated by sequestering carbon in reafforestation schemes, new plantations, and timber products. Wood biomass is a renewable carbon-neutral fuel.

The FAO has concluded that, over the period 2005–2050, effective use of tree planting could absorb about 10–20% of man-made emissions – so clearly we need to monitor the condition of the world's forests very closely (both reafforestation and deforestation) as they must be part of any coordinated emissions mitigation strategy.[40]

[edit] Cultivated land Main articles: agriculture, Green Revolution.

Rice PaddyFeeding more than six billion human bodies takes a heavy toll on the Earth’s resources. This begins with the human appropriation of about 38% [41] of the Earth’s land surface and about 20% of its net primary productivity[42]. Added to this are the resource-hungry activities of industrial agribusiness – everything from the initial cultivation need for irrigation water, synthetic fertilizers and pesticides to the resource costs of food packaging, transport (now a major part of global trade) and retail. The benefits of food production are obvious: without food we cannot survive. But the list of costs is a long one: topsoil depletion, erosion and conversion to desert from tillage for monocultures of annual crops; overgrazing; salinization; sodification; waterlogging; high levels of fossil fuel use; reliance on inorganic fertilisers and synthetic organic pesticides; reductions in genetic diversity by the mass use of monocultures; water resource depletion; pollution of waterbodies by run-off and groundwater contamination; social problems including the decline of family farms and weakening of rural communities.[43]

[edit] Extinctions Main articles: extinction, International Union for Conservation of Nature.

The Dodo (Raphus cucullatus)In line with human migration and population growth, species extinctions have progressively increased to a rate unprecedented since the Cretaceous–Tertiary extinction event. Known as the Holocene extinction event this human-induced extinction of species ranks as one of the worlds six mass extinction events. Some scientific estimates indicate that up to half of presently existing species may become extinct by 2100.[44][45]

Loss of biodiversity can be attributed largely to the appropriation of land for agroforestry. Current extinction rate are 100 to 1000 times their prehuman levels with more than 10% birds and mammals threatened, about 8% of plants and 5% of fish and more than 20% of freshwater species.[4]

[edit] Biological invasions Pueraria lobata, Kudzu infesting trees in Atlanta, GeorgiaMain articles: introduced species, invasive species.

Increasingly efficient global transport has facilitated the spread of organisms across the planet. The most stark examples are human diseases like HIV AIDS, mad cow disease and bird flu but invasive plants and animals are now, after climate change and land clearing, the greatest threat to native biodiversity.[46] Non-indigenous organisms often quickly occupy disturbed land but can also devastate natural areas where, in the absence of their natural predators, they are able to thrive.

[edit] Freshwater Main articles: freshwater, desalination, limnology, list of countries by freshwater withdrawal, list of countries by total renewable water resources, water resources, water crisis.

River Fluvia, CataloniaFreshwater habitat is the world’s most vulnerable of the major biological systems due to the human need for potable water for food irrigation, industry and domestic use. Human freshwater withdrawals make up about 10% of global freshwater runoff. [14] and of this 15-35% is considered unsustainable - a proportion that is likely to increase as climate change worsens, populations increase, and water supplies become polluted and unsanitary.[33]

In the industrial world demand management has slowed absolute usage rates but in the developing world water security, and therefore food security, remain among the most important issues to address. Increasing urbanization pollutes clean water supplies and much of the world still does not have access to clean, safe water.[4]

[edit] Indirect global environmental impacts Main article: appropriate technology

The direct impacts on the environment described above are the result of a long chain of causal factors, which is why managing direct human impacts on oceans, atmosphere and land is sometimes called "end of pipe" management; it does not manage the indirect "start of pipe" drivers of this impact which can be reduced to three fundamental factors:

People - our numbers and consumption patterns (resource use) relate directly to environmental impactspopulation numbers levels of consumption (affluence) impact per unit of resource use (which is a result of the technology used) This has been expressed through an equation: [47]

I = PAT

where: I = environmental impact P = population A = affluence T = technology This equation has been criticised because: affluence may have positive and negative impact due to the fact that it could either provide the means to tackle environmental problems or promote a higher consumption rate; the equation does not include social considerations such the effect of efficient environmental governance; it is difficult to apply in a realistic and useful way. [48] Nevertheless, it provides a strong starting point for discussion.

Addressing sustainability now focuses much of its attention on managing levels of consumption and resource impact by seeking, for example, to modify individual lifestyles, and to apply ideas like ethical consumerism, dematerialisation and decarbonisation, while at the same time exploring more environmentally friendly technology and methods through ecodesign and industrial ecology.

At present individual and household use of resources like energy and water is monitored through domestic water and energy bills and car fuel use – but much greater quantities of these resources are embodied in the goods and services we use. In the same way society as a whole tends to consider environmental management in terms of direct impacts rather than their driver - human consumption. Patterns of consumption must reflect the cleverer use of resources: e.g. using renewable energy rather than fossil fuels and fewer embodied resources in goods and services.[49] [50]