EcoRadio

Category: Articles

  • WAVE POWER

     

    This type of power generation is not a widely employed technology, with only a few experimental sites in existence. The market potential for hydrokinetic energy is vast, ranging from small-scale distributed generation applications to large-scale power plants.

    Pelamis wave

    In general, large breakers are more powerful. Specifically, power is determined by height, speed, wavelength, and water density. The size is determined by wind speed and fetch (the distance over which the wind excites the water) and by the depth and topography of the seafloor (which can focus or disperse the energy). A given wind speed has a matching practical limit over which time or distance will not produce larger waves. This limit is called a “fully developed sea.”

    This power source could yield much more energy than tidal power. Tidal dissipation (friction, measured by the slowing of the lunar orbit) is 2.5 terawatts. The energy potential is certainly greater, and the power of the sea in this form could be exploited in many more locations. Countries with large coastlines and strong prevailing winds (notably, Ireland and the UK) could produce five percent or more of their electricity from this source of power. Excess capacity (a problem common with intermittent energy sources) could be used to produce hydrogen or smelt aluminum.

     

    A floating buoy, submerged system or an offshore platform placed many kilometers from land is not likely to have much visual impact. Onshore facilities and offshore platforms in shallow water could, however, change the visual landscape from one of natural scenery to industrial. These are considerations, but ultimately we need to balance the need for sustainable energy against visual impact. Which would you choose between?

    During September 2008 the Pelamis technology pictured above became the world’s first commercial sea power plant converting waves into electricity. Situated off Portugal’s coast the project is expected to expand nearly 10-fold in the coming years.

    Generating a total of 2.25 megawatts, the power is enough to supply 1,500 households the project cost is reported to be around 8.5 million Euros (US$12.55 million).

    Although the price is not currently competitive, the project was possible due to the feed-in tariff in Portugal.

     

  • Other food action projects

    In the future, we will be working with local councils to get food projects happening on public land, to build resources in community gardens that people can take home to grow food on their own land, and to put staple foods into people’s back yards. We will start work on these projects once we have Front Yard Food up and running successfully.

    The articles

    The articles in this section are specifically about action that you can take in your community to create a robust local food supply. We are tracking a number of different approaches to getting local food happening within communities. They include:

    • Front Yard Food
    • Community Supported Agriculture
    • Allotments
    • Community Gardens
    • Agisting vegetables
    • Revitalising the suburbs

    man grows own food

    For related news items, head on over to the Sustainable Settlement news section of this site. As well as news about new farming and horticultural approaches, there are a range of articles about protests against the corporatisation of the food chain.

  • Front Yard Food

    This is a program to encourate people to help each other grow food. Many older people have gardens they can no longer keep up. Many people do not have enough experience to grow food successfully. By helping each other, we can create abundant food, in the community.

    To build momentum with this project we are coordinating the efforts of If you’d like to help, please register here.

    If you have, or know about, great food plants in your area, you can submit photographs and stories to this site. You will need to register first, and then we will grant you permission to upload stories and content. This step is necessary to reduce the amount of spam and junk that gets posted to the site.

    We look forward to working with you.

  • Are there limits to population growth in Australia?

     

    Australia has a high population growth rate compared with other high-income nations, mainly because of its high level of immigration. Although birth rates are below replacement level, there is also a natural increase in population levels. This is due to the lag effect of increases in population a generation ago, which resulted in increased numbers of women of child-bearing age. There is very little agreement among scientists as to how many people Australia can support, and even less about what environmental impact high levels of population would have. Some biologists, geographers and environmentalists argue that Australia already has more people that the environment can cope with, and that a sustainable population level would be more like ten million people.

    .

    The case against limits to growth of population in Australia

    Land degradation has sometimes been attributed to population levels. But the NPC’s population issues committee argues that Australian soils are in fact feeding more than fifty-six million people (both within and outside Australia), and that they provide wool and cotton for even more people. Moreover, it argues that the damage done to the soils was done by very small populations: the colonial settlers who cleared the land and the farmers (now less than 5 per cent of the total population) who still clear the land and sometimes cause further soil erosion. Similarly, mining also provides the needs of a wider population. The committee argues that the “environmental impact of any industry which exports a very large proportion of its output is therefore weakly related to domestic population needs and requirements” (pp. 41-2).

    It has also been argued by Lyuba Zarsky, an economic consultant, that even coastal tourist development is a result of economic growth in the Asia&endash;Pacific region rather than pressures from population in Australia. “While immigration can exacerbate environmental problems, strong curbs on immigration by themselves will do little to restore Australian farmland, improve forestry practices, or conserve coastline” (1991, p. 125).

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    Carrying Capacity

    Population biologists sometimes talk about the ‘human carrying capacity’ of an area. This refers to the ‘maximum rate of resource consumption and waste discharge that can be sustained indefinitely in a defined region without progressively impairing ecological productivity and integrity’ (French 1991, p. 123). Another term used is ‘cultural carrying capacity’, which recognises that people will not find it desirable to live at the limits of human carrying capacity because the quality of life would be unacceptable. The world could, as indicated above, support many more people living a subsistence lifestyle&emdash;but is that what we want?

    The impact that a population has on an area obviously depends on their practices and culture, particularly on how many resources they consume and the volume of wastes they discard. J. H. Cushman and Andrew Beattie, population biologists, point out that the Australian continent ‘could support more Swedes (and far more Ethiopians) than Americans’ (1992) because of the differences in the amounts people from these nations consume (assuming they did not start consuming like Australians when they got here, since Australians consume almost as much per person as North Americans).

    Environmental degradation is a product of numbers of people, consumption per person and the environmental impact of each unit of consumption. Increasing numbers of people in Australia will affect Australia’s resource use unless the extra numbers can be compensated for by lower consumption per person or increased resource&endash;use efficiency. In a study for the NPC, G. McGlynn estimated that, in order just to keep resource use constant while population and incomes were increasing at current rates, a 3.11 per cent increase in efficiency of resource use per year would be required. However, another study cited by the NPC showed that increases in efficiency have not exceeded 2.1 per cent since 1965. (Population Issues Committee 1992, p. 44)

    Source: Sharon Beder, The Nature of Sustainable Development, 2nd ed. Scribe, Newham, 1996, pp. .

    © Sharon Beder

  • Effects of overpopulation

  • Changes in atmospheric composition and consequent global warming[146] [147]
  • Irreversible loss of arable land and increases in desertification[148] Deforestation and desertification can be reversed by adopting property rights, and this policy is successful even while the human population continues to grow.[149]
  • Mass species extinctions.[150] from reduced habitat in tropical forests due to slash-and-burn techniques that sometimes are practiced by shifting cultivators, especially in countries with rapidly expanding rural populations; present extinction rates may be as high as 140,000 species lost per year.[151] As of 2007, the IUCN Red List lists a total of 698 animal species having gone extinct during recorded human history.[152]
  • High infant and child mortality.[153] High rates of infant mortality are caused by poverty. Rich countries with high population densities have low rates of infant mortality. [8]
  • Increased chance of the emergence of new epidemics and pandemics[154] For many environmental and social reasons, including overcrowded living conditions, malnutrition and inadequate, inaccessible, or non-existent health care, the poor are more likely to be exposed to infectious diseases.[155]
  • Starvation, malnutrition[118] or poor diet with ill health and diet-deficiency diseases (e.g. rickets). However, rich countries with high population densities do not have famine.[156]
  • Poverty coupled with inflation in some regions and a resulting low level of capital formation. Poverty and inflation are aggravated by bad government and bad economic policies. Many countries with high population densities have eliminated absolute poverty and keep their inflation rates very low.[157]
  • Low life expectancy in countries with fastest growing populations[158]
  • Unhygienic living conditions for many based upon water resource depletion, discharge of raw sewage[159] and solid waste disposal. However, this problem can be reduced with the adoption of sewers. For example, after Karachi, Pakistan installed sewers, its infant mortality rate fell substantially. [160]
  • Elevated crime rate due to drug cartels and increased theft by people stealing resources to survive[161]
  • Conflict over scarce resources and crowding, leading to increased levels of warfare[162]

    • [edit] Mitigation measures

    While the current world trends are not indicative of any realistic solution to human overpopulation during the 21st century, there are several mitigation measures that have or can be applied to reduce the adverse impacts of overpopulation.

  • PAUL EHRLICH AND THE POPULATION BOMB