Showing results for: Water
While 72 percent of the Earth is covered in water, only 3 percent consists of precious freshwater, and of that, over two-thirds is stored in ice caps and glaciers. Currently, about 1.1 billion people chronically lack access to drinking or irrigation water, and a total of 2.7 billion experience water scarcity for at least one month of the year; this is predicted to increase in the future due to unsustainable extraction of water from aquifers and rivers, and to climate change and the growing importance of other competing uses such as industrial developments and urbanisation. Since industrial times, more than half the world’s wetlands have disappeared. Agricultural production is the major user of water, utilising some 70% of all irrigation water and its use is often highly inefficient. The agri-food sector is also a major source of water pollution, via its use of pesticides and synthetic and organic fertilisers, contributing to eutrophication.
This book reframes the debate around water and food security, focusing on the rights of marginalised people instead of only discussing irrigated agriculture.
This book, originally published as a special issue of Water International, explores how the concept of “virtual water” is relevant to agriculture, trade and sustainability.
This paper uses climate models to estimate that average precipitation across many crop production areas will change by more than natural variability throughout the 21st century. Changes are seen even if emissions are relatively low, but meeting the Paris climate goals could reduce the extent of cropland that is affected.
Over half a million acres of irrigated farmland may have to be permanently taken out of agricultural use in the San Joaquin valley in California in order to conserve groundwater, according to this report by the non-profit Public Policy Institute of California. The report suggests using the land for generating solar energy, restoring ecosystems or managing flood risk by restoring floodplains.
Growing millet next to a woody shrub native to West Africa could increase biomass by over 900% compared to growing millet alone, according to this paper. The shrub, Guiera senegalensis J.F. Gmel, has tap roots that can reach water deep in the soil. The study traced the movement of water from the shrub’s deep roots to the millet stems in a simulated drought.
Wastewater canals used to irrigate urban agriculture in Burkina Faso may harbour dangerous microbes such as tuberculosis and genes that give microbes resistance to antibiotics, according to this research paper. The canals sampled by the researchers were designed to protect against flooding, but are used to water agricultural fields. The canals, which are not regularly cleaned, receive sludge, solid waste, wastewater, and effluent from a hospital, a market, houses and a slaughterhouse.
This paper surveys 195 cities in the United States and finds that the number of water conservation measures adopted in a city depend on both the climate (drier cities tend to have more water conservation measures than wetter cities) and political leanings (cities that lean towards the Democrats have more water conservation measures than Republican-leaning cities).
A project in Ladakh, India, creates “ice stupas”, a form of artificial glacier, to complement intermittent water flow from retreating natural glaciers. Water from streams is sprayed from vertical pipes during the winter, freezing into pointed mounds, which melt slowly throughout the year, irrigating crops in the summer.
Some avocado plantation owners in Chile are illegally diverting water from rivers and leaving local villagers without enough water, according to a feature in the Guardian. Demand for avocados has increased by 27% in the UK in the last year. Activist Veronica Vilches claimed that local people are getting sick because of the lack of water, while activist Rodrigo Mundaca says that the water provided to resident by trucks is of poor quality.
Researchers from Nasa have used satellite data to identify areas where freshwater reserves have increased or decreased. The study found that in 14 regions, the changes were likely due to human factors (e.g. groundwater pumping), and in 8 areas, the changes were caused mainly by climate (e.g. drought or ice-sheet melting). Freshwater availability decreased in several areas including northern India, north-east China, the Caspian and Aral Seas and some of the Middle East.
Structural changes in the food system such as replacing half of animal proteins with plant-based proteins could significantly marine eutrophication in the North-East Atlantic, according to a recent paper. The authors addressed the question of whether Western Europe can reduce nitrogen and phosphorus runoff to coastal areas without endangering food security.
A report by WWF, The Rivers Trust and The Angling Trust finds that only 14% of rivers in England are classed as healthy, with damage being caused by poor farming and land management practices, for example by degraded soil being washed into watercourses and agricultural chemicals contaminating groundwater. The report sets out a strategy for managing both soil and water health, including stricter control of slurry storage, incentives for farmers to plant woodland or create wetland habitats and creating an advice service for farmers and land managers.
In this TED talk, ocean expert Nancy Rabalais discusses the “dead zone” in the Gulf of Mexico - an area of the ocean where there isn’t enough oxygen to support sea life. Fertiliser runoff from farmland further up the Mississippi River is causing the dead zone, according to Rabalais. She says that solutions could include growing perennial grains and using precision fertilisation.
This article examines global overuse of freshwater resources and how more sustainable irrigation practices could impact other environmental and developmental targets in the SDGs. It finds that the main likely effects are 1) increased food prices due to lower productivity and/or production costs as water prices increase, and 2) cropland expansion and associated extra GHG emissions of 0.87 gigatonnes of carbon.
The U.S. Geological Survey (USGS) has released a worldwide map that details croplands in high resolution in an ongoing effort to monitor croplands and water use.