Population and the environment

• Where is population decreasing?

  Eastern Europe, 0 - -1% change
• What is carrying capacity?

  The maximum population size that an environment can sustain.
• What is undernourishment?

  Insufficient intake of nutrients leading to malnutrition.
• What is malnutrition?

  Deficiency in nutrients through not having enough to eat or eating a balance diet
• How is undernourishment being combated?

  Through initiatives implemented by the UN such as improving agricultural practices, promoting sustainable food systems, providing access to nutritious food, and addressing poverty and inequality.
• How much food is wasted per year in the UK?

  18 million tonnes in landfill per year
• What is overnutrition?

  Excessive intake of nutrients, leading to accumulation of body fat that impairs health.
• Where is the highest average daily calorie intake per day?

  USA at 3480 - 3769
• Where is the lowest average daily calorie intake?

  Sub-Saharan Africa and Bolivia at less than 1890 per day
• What are the agricultural inputs?

  Precipitation, temperature, drainage, labour, agrochemicals, machinery, seeds and energy
• What are the agricultural processes?

  Growing crops, rearing livestock, daily routines, seasonal patterns and hazard perception
• What are the agricultural outputs?

  Crops and livestock.
• How can soil quality impact agricultural yield?

  Through its capacity to retain water, pH, depth and structure.
• What is ClimaRice and what are its findings?

  A Norwegian Project which has researched into the impacts of the availability of water and what will happen if rice grains were sown directly into the soil. The key findings were broadly positive and include higher yields, lower labour costs and reduced methane emissions. However, there are increased amounts of weeds which means more expensive herbicides are needed more.
• What are the knock-on effects of monsoon rains becoming uncertain?

  • Food insecurity as dry season relies on excess water to continue growing crops
  • Increased stress on groundwater
  • Extreme poverty and starvation
• What are the knock-on effects of permafrost melting?

  • Indigenous people having to migrate
  • Larger area where crops can grow
• What is the nutrient cycle?

  A system where energy and matter are transferred between living organisms and non-living parts of the environment.
• What are the features of tropical red latosol soil?

  • Up to 30m deep
  • Quick nutrient cycle
  • Tropical rainforest
  • Deforested to gain access for mineral exploitation
• What are the features of podsol soil?

  • Rarely exceeds 1m deep
  • Thin litter of pine needles
  • Taiga regions
  • Poor nutrient cycling
• What was said about the soil World Economic Forum (2012)?

  Soil is being lost at between 10 and 40 times the rate at which it can be naturally replenished. 40% of soil is classed as either degraded or seriously degraded.
• What are they key facts about soil erosion?

  • Poor land management by a rising population has allowed overgrazing and deforestation
  • Deep ploughing up and down slopes as well as monoculture both aid the removal of fertile topsoil, reducing soil thickness and the room for roots
  • Hedgerows have been removed in the south-east of England to increase the cultivable area and mechanical efficiency
• What is waterlogging?

  Waterlogging occurs when the water table rises to the point of soil saturation and there is insufficient oxygen in the pore spaces for plants roots to respire adequately. Causes an anaerobic environment where root tissues decompose and if not dealt with. In hot climates, waterlogged soils provide mosquitoes which transmit diseases such as malaria.
• What causes waterlogging?

  • Rainfall exceeds the rate that soils can absorb or the atmosphere can evaporate
  • Gentle relief restricts throughflow of infiltrating soil water
  • Relief basins or depressions encourage accumulations of water
  • Seepage from rivers, canals and reservoirs infiltrate soils
  • Excessive irrigation water is used to flood fields
• Why isn't salinisation a problem in well-drained areas?


  The salts are leached out of the soil by infiltration and percolation so salinisation isn't a problem as the soil has sufficient precipitation and efficient irrigation.
• How does poor drainage lead to waterlogging and salinisation?

  Poor drainage leads to waterlogging, the water table rises and brings dissolved salts towards the surface. When the water evaporates, a crust of concentrated salt is left on the surface.
• What is soil texture?


  The proportions of sand, silt and clay influences its characteristics and workability.
• What is soil structure?

  How the individual particles are grouped together.
• What is soil management?

  Preserving and protecting vegetation cover. Afforestation and reforestation are the best long-term solution to soil erosion as once the trees have grown, the foliage shades the soil from the sun and intercepts rainfall, roots bind soil together and reduce surface runoff.
• What are soil management techniques?

  • Terracing
  • Contour ploughing
  • Crop rotation
  • Selective afforestation
  • Controlled grazing
  • Improved drainage
• What is food availability?


  Food must be available in sufficient quantities and on a consistent basis. Considers stock, production and the capacity to bring in food from elsewhere.
• What is food access?

  People must be able to regularly acquire adequate quantities of food, through purchase, and other methods.
• What is food utilisation?

  Consumed food must have a positive nutritional impact on people. This includes cooking storage and hygiene practices, individual's health, water and sanitation.
• What is the food security risk index?

  • Identifies regions whose food security is at risk due to internal and external factors
  • Most extreme areas - sub-Saharan Africa, Afghanistan and Haiti
  • 2016 - one in nine were suffering from chronic undernourishment
  • MDG food security targets were hampered by economic conditions and natural events
  • Hunger rates in countries that are enduring crises are three times higher than elsewhere
• What are the strategies to ensure food security?

  • Improved agricultural productivity - higher yields from high-yielding varieties of seed, agrochemicals and mechanisation
  • Economic growth - expands fiscal revenue base necessary to fund social transfers and other assistance programmes
  • Expansion of social protection - correlates strongly with progress in hunger reduction. Through cash transfers, food vouchers, health insurance or school meal programmes, the FAO estimate 150 million are prevented from falling into extreme poverty
• What are the key facts about the Green Revolution?

  • In the 1960s, countries such as the UK, Italy, Mexico and the Philippines were conducting hybridisation (cross-breeding) experiments to develop new varieties of crops
  • For example, in Mexico, hybrid wheat and maize strains were developed to withstand heavy rain, strong winds and diseases, which doubled yield.
  • Increased use of agrochemicals and chemical fertilisers doubled crop yield in tropical areas as well as locust plagues
• What are the negative impacts of the Green Revolution?

  • High economic and social costs - only richer farmers could afford to buy and run tractors - leading to rural depopulation
  • Poorer farmers took out loans to buy new seeds and fertilisers but were often unable to repay them, forcing the sale of their land
• What are the key facts about the Gene Revolution?

  • Genetic modification (GM) is highly controversial as it involves taking DNA from one plant and introducing it to another to make it more resistant to drought, pests or diseases
  • 2014 - 18 million farmers in 28 countries growing GM crops - however due to unknown health implications, they are banned in 40 countries including the UK
• What are crop wild relatives?

  Link to the Gene Revolution

  Wild species closely related to common food crops which are vital to food security as it makes crops more resistant to climate change, waterlogging, salinisation, crops and diseases.
• What is the Adapting Agriculture to Climate Change Project at Kew Gardens?


  Collecting seeds from the wild plant relatives of 29 common crop plants to breed new and useful traits into commercial crops.
• What is health?

  The state of physical, social and mental well-being.