Carrying Capacity – Page 8

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17 November, ABC Science, New map of Earth’s groundwater to help estimate when it may run out. Less than 6 per cent of ground water in the upper two kilometres of the Earth’s landmass is renewable within a human lifetime, according to a new map showing the world’s hidden groundwater. “This has never been known before,” said the study’s lead author, Dr Tom Gleeson of the University of Victoria in Canada. “We already know that water levels in lots of aquifers are dropping. We’re using our groundwater resources too fast -faster than they’re being renewed.” Using data and computer models, an international group of hydrologists has produced the first data-driven estimate of the Earth’s total supply of groundwater. “Since we now know how much groundwater is being depleted and how much there is, we will be able to estimate how long until we run out.” The study, published in the journal Nature Geoscience, estimated a total volume of underground water to be almost 23 million cubic kilometres, of which 0.35 million cubic kilometres is younger than 50 years old. Underground water is found beneath the Earth’s surface and is recharged by rain, snow or water that leaks from the bottom of lakes and rivers. Its age can be a few months to millions of years. It can be found as deep as nine kilometres, according to the United States Geological Survey. “Since we now know how much groundwater is being depleted and how much there is, we will be able to estimate how long until we run out,” Dr Gleeson said. Read More here

13 November 2015, Climate News Network, Global warming drains the water of life. Melting snowpack in Turkey’s Lesser Caucasus mountains. New research warns that rising temperatures are reducing the mountain snow on which billions of people in lowland areas depend for their water supply. Up to two billion people who depend on winter snow to deliver their summer water could see shortages by 2060 as upland and mountain snowpacks continue to dwindle. An estimated 300 million people could find, 45 years on, that they simply won’t have enough water for all their needs, according to new research. Climate change driven by rising atmospheric levels of carbon dioxide – in turn, fed by human combustion of fossil fuels – may already be affecting global precipitation. Researchers have consistently found that much of the world’s drylands will increase as global average temperatures rise. But warmer temperatures increasingly also mean the water that once fell as snow, to be preserved until the summer, now falls as winter rain, and runs off directly. The snow that does fall is settling at ever higher altitudes and melting ever earlier. Reliable flow This is bad news for agricultural communities that depend on a reliable flow of meltwater every summer. California is already in the grip of a sustained drought, made worse by lower falls of snow. Great tracts of Asia depend on summer meltwater from the Himalayan massif and the Tibetan plateau. Justin Mankin, an environmental scientist at Columbia University’s Earth Institute in the US, and colleagues report in Environmental Research Letters journal that they studied 421 drainage basins across the northern hemisphere. Read More here

1 October 2015, , State of the World Report World Institute, Land “Grabbing” Grows as Agricultural Resources Dwindle. As global agricultural resources shrink or shift, countries are crossing border to obtain new farmlands. Since 2000, more than 36 million hectares—an area about the size of Japan—has been purchased or leased by foreign entities, mostly for agricultural use. Today, nearly 15 million hectares more is under negotiation (www.worldwatch.org). “Farmland is lost or degraded on every continent, while ‘land grabbing’—the purchase or lease of agricultural land by foreign interests—has emerged as a threat to food security in several countries,” writes Gary Gardner, contributing author of the Worldwatch Institute’s State of the World 2015: Confronting Hidden Threats to Sustainability. About half of grabbed land is intended exclusively for use in agriculture, while another 25 percent is intended for a mix of agricultural and other uses. (The land that is not used for agriculture is often used for forestry.) Land grabbing has surged since 2005 in response to a food price crisis and the growing demand for biofuels in the United States and the European Union. Droughts in the United States, Argentina, and Australia, has further driven interest in land overseas. “Today, the FAO reports that essentially no additional suitable [agricultural] land remains in a belt around much of the middle of the planet,” writes Gardner. As a result, the largest grabbers of land are often countries that need additional resources to meet growing demands. Over half of the global grabbed land is in Africa, especially in water-rich countries like the Congo. Asia comes second, contributing over 6 million hectares, mainly from Indonesia. The largest area acquired from a single country is in Papua New Guinea, with nearly 4 million hectares (over 8 percent of the country’s total land cover) sold or leased out. Read More here

23 September 2015, The Conversation, Sustained economic growth: United Nations mistake the poison for the cure. On September 25 world leaders will meet in New York to formalise the new Sustainable Development Goals. These 17 goals will guide efforts to reduce poverty and increase well-being, without destroying the Earth. The Conversation is looking at how we got here, and how far we have to go. On the surface, the Sustainable Development Goals, soon to be confirmed by the United Nations, seem noble and progressive. They seek to free the human race from the tyranny of poverty and hunger while creating sustainable and resilient societies. But look beneath the surface of this pleasant rhetoric and one comes face to face with a far more ominous vision of development: a vision that is fundamentally compromised by corporate interests and ultimately doomed to failure, if not catastrophe. The defining flaw in the United Nations’ agenda is the naïve assumption that “sustained economic growth” is the most direct path to achieving the Sustainable Development Goals. This faith in the god of growth is fundamentally misplaced. It has been shown, for example, that for every $100 in global growth merely $0.60 is directed toward resolving global poverty. Not only is this an incredibly inefficient pathway to poverty alleviation, it is environmentally unsupportable. By championing economic growth, the Sustainable Development Goals are a barely disguised defence of the market fundamentalism that underpins business-as-usual. But in an age of planetary limits, sustained economic growth is not the solution to our social and environmental ills, but their cause. Read More here

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