Population and Environment Flashcards
What physical factors affect a sparse/small population
-Climate: Extreme temperatures, low annual precipitation, seasonal drought
- Soils: Permafrost, thin soils in mountains, soil erosion due to leaching and overgrazing
-Resources: energy and minerals in short supply
-water supply lacking in quantity or quality
What physical factors affect a large/dense
-Climate: temperate areas and even supply of sunshine
-Soils: Deep fertile soils in alluvial river basins
-Resources: energy and mineral resources readily accessible
-Reliable supply of good clean water
What are the Key population parameters
-Distribution
Describes the pattern of how population is spread over an area
The world has an uneven population distribution
-Density
-The number of people living in a certain area
-Usually measured in population per km2
-Numbers
The total amount of people living in an area
-Change
How population increases or decreases over time
Population is never static; the distribution, density and number is constantly evolving due
to various processes
Development processes describe what
how human societies advance over time due to technological change
Describe the Neolithic revolution
12,000 years ago, Development of farming practices and shift from small hunter-gatherer populations into larger, settled agricultural communities. More stable food supply leads to population growth
Describe the Industrial revolution
-1760 - 1850, With the invention of labour-saving machinery and discovery of large supplies of energy resources, manufacturing industry overtook agriculture as the largest sector of the economy in Britain and other major world powers
-People moved to cities in larger numbers and life expectancy increased as social
conditions (for e.g. sanitation and medicine) improved
-Many developing countries going through the same process today which leads to fast growing populations and urbanisation
Describe the green revolution
1960, Agricultural yields were maximised with new food technologies (e.g. hybrid seeds) and better farming techniques, particularly in less developed countries
More reliable food supply meant populations in developing countries increased quickly
How can Development processes reduce population totals
-Countries reaching an advanced stage with highly developed social systems mean life expectancy can be very high
-increasing proportion of the population is elderly so that death rates increase
-Population growth rate slows and in some cases total population falls
-Japan’s population is falling (2020 growth rate was -0.30%)
World population grew very ___ until 18th century
slowly until 18th century
From 10,000 BCE to 1700 CE the average growth rate was just 0.04% per year
____ growth in population since the mid 18th century
World population reached 8 billion in November 2022
Exponential
Despite the growth rate falling, world population is projected to continue to grow until approximately ___ when it could reach more than ___
2100, more than 11 billion
Approximately ___ of the world now lives in cities but this figure is projected to reach __by 2050 as urbanisation increases
The densest populations are in areas that have the most ___environmental conditions or where human development processes have occurred
55%, ,65%, favourable
Example of Population change rates vary with time
Global average growth rate has declined since around 1970
How does Population change rates vary over space
-Countries that went through Industrial Revolutions in the 18th and 19th centuries
experienced rapid population growth. Today those countries are developed and their
growth rates have fallen. In some cases they have fallen so much that their total
populations are in decline (e.g. Japan)
-The fastest population growth today occurs in developing countries that are rapidly
industrialising
How has Global food production has changed over time
-Increased significantly in the last 50 years (three times more food is produced today than
in 1970)
-Due to more land being put aside to grow crops and technological advancements
increasing crop yields
Global food production is ___ distributed over space
unevenly, due to Physical factors (climate, soils, relief and water availability) influence how much food can be grown in some areas
Human factors (economic resources and investment in technology) also determine the pattern
Why has Global food consumption also increased significantly in recent years
-Linked to levels of development
-More highly developed countries can afford to invest in food production technology to increase yields and can also afford to import more food if it can’t be grown locally
-Consumption by lower income countries has also increased as they have developed, but total consumption by these countries is lower and increasingly more slowly than in developed countries
Agriculture is an example of an ___system
open, Contains inputs, outputs and processes that turn inputs into outputs
Also contains feedbacks
Inputs of Agricultural Systems
Physical - precipitation, temperature, relief, soil fertility, drainage
Human - Labour
Economic - Seeds, replacement stock, agrochemicals, mortgage, tax, machinery, fuel
Processes in Agricultural Systems
growing crops, rearing livestock, daily routines, hazard perception
Outputs of Agricultural Systems
Crops, livestock, livestock patterns
Feedbacks in agriculture systems
profit for reinvestment
manure for fertiliser
hay for fodder
Productivity in subsistence agriculture systems
Food is produced to feed family or community and only excess sold or traded. Often also extensive.
i.e…
Nomadic pastoralism, West Africa
Productivity in commercial agriculture systems
Crops grown or livestock raised to sell for profit, Often also intensive i.e.
Large agribusiness growing grain in North America
Cattle ranching in South America
High outputs
Productivity in intensive agriculture systems
High yields per area of land as a result of large investment in capital or labour.
Horticulture in Netherlands (capital intensive)
Rice cultivation in India (labour intensive)
High outputs
Productivity in extensive agriculture systems
Small inputs of capital or labour per area, leading to low yields i.e.
Sheep farming in Yorkshire Dales, UK
Low outputs
How is Agricultural productivity is influenced by climate
-Precipitation levels and distribution determine water availability for plants and livestock
Steady year-round rain gives an area the best chance to capture and store water required
-Extreme rainfall can damage crops and arid areas need to import water for crops to survive
-Maximum and minimum requirements for high yield depend on the crop variety but in general mean annual temperatures between 6°C and 25°C allow for highest productivity and longest growing seasons
-Higher temperatures require more water supply to replace that which is lost to evapotranspiration
-High winds can restrict the growth of plants, particularly in grain crops, but in some locations local wind patterns can be beneficial
-The ‘chinook’ is a warm wind that melts snow in the Prairies of North America, prolonging a cereal’s growing season
How is agriculture productivity affected by soils
-Level of nutrients in the soil varies across the world and different crop varieties require different soil characteristics to thrive
-Potatoes grown in the UK require the PH of the soil to be greater than 4
Other important soil characteristics are depth, structure, mineral content, moisture retention and aeration
-Soil degradation and soil erosion can decrease productivity
Characteristics and distribution of tropical mosoons
-The tropical monsoon climate is characterised by a distinct hot, wet (monsoon) season and a cooler dry season
-Temperature can average 30°C in the monsoon season and humidity is also very high
-Average rainfall is around 2000mm for the season (south-east UK receives just over 600mm per year)
-Cyclones (tropical storms) are frequent towards the end of the rainy season
What determines monsoon season
the annual movement of the Inter Tropical Convergence Zone
how does the Inter Tropical Convergence Zone work
-In south-east Asia, between May and October the ITCZ brings the strongest sun over the continental landmass, heating the land and causing large masses of air to rise in —low pressure zones.
-Moist, warm air from the Indian Ocean to the south-west gets sucked in to replace the rising air over the continent and this brings heavy monsoon rainfall
In November the ITCZ moves south and the process reverses so that cooler, drier air moves from the continent back towards the Indian Ocean
Where does the ITCZ occur
Occurs mainly on the eastern side of continents in the Tropics from about 5-20°N and S of the Equator
agriculture in monsoon regions relies heavily on what
the warm wet conditions and this can produce high yields and support large populations
More than ___ billion people live in the Asian countries that are visited by summer monsoon winds
4
How does monsoon season help local farms irrigate crops
Many areas in these countries do not have large irrigation systems but the summer monsoon rainfall fills aquiders and other groundwater stores for the rest of the year
What crops depend on monsoon season
-Rice and tea are some crops that rely on the summer monsoon
-Dairy farms, which help make India the largest milk producer in the world, also depend on the monsoon rains to feed the cows
How is the Industry and energy supplies fed by the monsoon climate system
-In India and Southeast Asia a large amount of electricity in the region is produced by hydroelectric power plants, which are driven by water collected during the monsoons.
-This electricity helps to power hospitals, schools, and industry and is as vital to the local economy as the crops the rain helps to grow
Characteristics and Distribution of polar tundra climate
-Polar climates cover 20% of the earth’s surface
-Found in both northern and southern hemispheres above 66° latitude
-Very low mean annual temperatures in all Polar regions, arctic:-40 — +10 (degrees)
and Antarctica:-80
-Precipitation levels less than 100mm per year in all polar regions, making them (polar) deserts
-Tundra refers to areas of permafrost that fringe the ice caps at both poles
Which countries can be found in polar regions
Northern Russia, northern Scandinavia, Greenland, Northern Canada
Continent of Antarctica to the South
Why is population low in polar tundra
Due to the harsh climate and thin soils, the polar tundra climate supports very low population numbers, despite its large area
Around __ million people live within the Arctic Circle
4
Examples of inhabitants
-The ten largest settlements are in northern Russia with Murmansk (300,000 people) being the biggest
-Small indigenous groups also occupy the region, such as the Innuit in northern Canada and Greenland, and the Sami of Northern Europe
-These groups migrate with the seasons to be close to food sources
Are there permanent residents in antartica
There are no permanent residents in Antarctica but some scientific research bases support small temporary populations of scientists in the summer months
What is agriculture like in these regions and why is it like this
-Agriculture is mainly subsistence, with low productivity
-Because crops struggle to grow in the thin, frozen soils, peoples’ diets are mainly meat-based and traditional methods of fishing, trapping and hunting secure supplies, alongside reindeer herding
Economic activities in polar tundra regions
-Development of buildings, roads and industry is restricted by the frozen ground and their design needs to be adapted so as not to melt the permafrost
-Cruise ships visit the regions during the summer months, bringing much needed income to local economies in the form of adventure tourism
-Commercial fishing and trade occurs in the Arctic during the summer months when sea ice melting allows shipping routes to be accessed
-Polar regions contain vast untapped reserves of oil, gas and other minerals and there is pressure on the regions to exploit these resources
How will climate change effect agriculture
-Distribution of tropical plant pests likely to widen
-Soil problems such as erosion, desertification, and salinization are projected to increase in some areas due to higher temperatures. This will continue to make arable land unusable. (On the flip side, thawing permafrost will increase agricultural productivity in colder regions)
-Rising sea levels due to melting sea ice is thought to cause flooding in low lying areas, such as Bangladesh, devastating crop yields
-
Examples of how climate change will effect agriculture
- In Asia, it is predicted that per 1°C temperature rise, rice yields will decrease by 20%.
- Severe droughts in East Africa are thought to be worsening due to global warming, especially in Kenya and Somalia. rainfall is becoming more scarce and unpredictable . In the past 10 years, 7 years have experienced severe droughts. With 70% of Africa’s agriculture being rainfed,
- Northern Europe and America may see increased productivity due to increased growing season
What are Zonal soil characteristics
-Soils form the layer between the bedrock and the surface of the ground
-They consist of weathered bedrock and decomposed organic matter from plants
-Climate is a key factor in how quickly bedrock weathers and organic matter decomposes
-Zonal soils form over long periods of time, typically taking 100 years for every inch of soil
-Cross profiles of soils show distinct layers, known as soil horizons
-Two examples of zonal soils are tropical red latosols and taiga podsols
Tropical Red Latosol is Located in ____ biome where weathering of bedrock and decomposition of plant matter rapid due to warm and humid climate, forming deep soils ___ metres thick
tropical rainforest, 30-40
Why does the tropical red latosol have a thick top horizon
High net primary production (NPP) due to high abundance of surface vegetation (leaf litter)
Why is the fertile layer of tropical red latosols thin
Leaf litter decomposes quickly into humus and nutrients are absorbed rapidly by rainforest vegetation
How does the soil gain its red colour
Leaching occurs downwards due to rainfall exceeding evapotranspiration rates, iron compounds are left behind in this layer
How is laterite horizon formed in tropical red latosols
build up of minerals in base layer forms a clay like substance
Why is crop growth hard in tropical regions
land cleared of areas of forest has a short lived nutrient supply in top layers
What sustainable farming practices do local indigenous people use
- Slash and burn techniques used ins small areas of forest add nutrients to the soil
-Crop rotation after 1 season allows a plot of land to recover and re-add nutrients to the soil
What is increasing land use competition in tropical rainforests
-urban growth
-cattle ranching
-cash crops increasing i.e. palm oil - 19,000 hectares
-laterite clay is a good building material
-timber
Where do Podsol (or Podzol) soils form
under coniferous woodland or heather moorland in taiga biomes (also known as boreal forest in North America)
Places podsols can be found
Occupies a large belt of land just south of the tundra biome of the Arctic Circle in North America, Northern Europe and Northern Russia
Why are podsols shallow (rarely greater than 1m)
Weathering of bedrock and decomposition of plant matter slow due to a cold winters and cool summers
Characteristics of layers of podsols
-surface layer - pine needles from coniferous trees
-Sub surface layer, thin and acidic. Evergreens do not take up nutrients so when pine needles fall they are nutrient poor, dark in colour
-precipitation exceeds evapotranspiration so surface water infiltrates and percolates causing downwards leaching, forming grey layer of sand and silt
-Leached minerals accumulate above bedrock in a hard pan of iron and aluminium
How do podsols influence human activities
-Limited crop growth due to acidic soils and limited nutrients
-Arable farming made possible in some regions using lime and artificial fertilisers
-Hard pan makes draining hard, so waterlogging is frequent -makes ploughing with heavy machinery difficult
-forestry is dominant industry in region
-low soil temps mean trees can take up to 100 years to reach maturity
-large areas deforested due to commercial logging - Europe has lost more than half of its forests in the past 6,000 years.
- podsols in coniferous forests support gaame in North UK - employs 2000, generates £150 million per year
What is Soil Erosion
Wearing away of fertile topsoil by wind and water
Causes of soil erosion
-Deforestation and overgrazing exposes soil
-Farming practices such as ploughing downslope can lead to rilling
-Relief as soil more likely to be washed away on steep slopes
-Climate as water erosion more likely after heavy rainfall and wind erosion more likely in very dry conditions
Impacts soil erosion has on agriculture
-Soil becomes less fertile as nutrients are removed
-Soil’s ability to retain water reduced
-Can cause rills and gullies that make the cultivation of paddocks impossible
-Results in lower yields and higher production costs
-Around 10 million hectares of land abandoned each year due to lack of crop productivity
How can people manage soil erosion
-Afforestation to allow roots to stabilise soil and return leaf litter nutrients - 360,000 trees were planted outside woodland equivalent to about 499 hectares of additional tree canopy in UK 22-23
-Fertilisers added to soils to improve nutrient content
-Rotate crops to allow soil to recover before planting again
-Planting natural windbreaks, such as hedges
-Ploughing across, rather than down, slopes
-Terracing on steep slopes
What is waterlogging
When pores between soil particles fill with stagnant water
Causes of waterlogging
-impermeable soils that have few pores, such as clay
-Heavy rainfall in areas where rates exceed evapotranspiration
-Over-irrigation
-Hard-pans can stop percolation and create an impermeable layer
How does waterlogging impact agriculture
-Gleying leads to soil infertility
-Rotting of plant roots
-Weeds outgrow crops as can survive waterlogged conditions better
-Reduced soil temperature leading to slower crop growth
How to manage waterlogging
-Improving field drainage
-Sustainable irrigation systems - drip, sprinkler, and micro spray reduce water loss
-Adding sand to clay soils to increase pore spaces
What is salinization
Accumulation of salt within soil
Natural causes of salinization
-High temperatures and low precipitation lead to high rates of evaporation so that salts left on ground surface
-Sea-level rise can draw salt up into soil in coastal areas
Human causes of salinization
-Over-abstraction of groundwater for irrigation leads to saltwater intrusion
-Over-irrigation of water containing dissolved salts
-Fertilisers containing salts left in soil i.e - Potassium chloride (potash) has the highest salt index among the common dry fertilizer products
Impact salinization has on agriculture
-3000-6000 ppm of salt can be toxic to plants
-Decreases osmotic potential of soil so plants can’t get required water
-Pea and bean crops particularly vulnerable
-Salinisation in San Joaquin Valley, California, projected to cost the state $1-1.5 billion
How can people manage salinization
-Drip-irrigation and soil moisture monitoring
-Selection of deep-rooted crops to increase water retention
-Soil flushing with water (although this moves problem elsewhere)
-Using fertilisers with low salt content
-Strategies to avoid waterlogging (as above)
What is Structural Deterioration
Pore spaces are lost as the structure of the soil is squeezed or collapses
Causes of structural deterioration
-Removal of vegetation so that roots no longer there to support the soil
-Soil compaction from heavy farm machinery or livestock trampling
-Salt in soil causes clumping together of clay particles
Impact structural deterioration has on agriculture
-Lack of space in soil for infiltration of water to occur so crops dry out quickly
-Plant roots unable to grow through compacted soil as they need air pockets to survive
-Farmers unable to till and plough the soil if it is too compacted
How can people manage structural deteriorations
-Avoiding use of heavy machinery
-Move livestock around to avoid compaction
-Introducing more organic matter into the soil to encourage the soil to aggregate together to increase number of pore spaces
What is Food Security
Refers to humans’ ability to access a diet of sufficient quantity and quality to meet their daily health needs and lead an active life
To assess food security, which dimensions should be considered
-Peoples’ physical availability of food
-Peoples’ physical and economic access to food
-The quality of the available food and how it is stored and prepared
Examples of Large spatial variations in food security
-North America, Europe, Japan and Australasia are the regions considered most food secure
-The greatest risk of food insecurity is in sub-Saharan Africa, Afghanistan and Haiti
what is increasing the risk to food security in many regions of the world
Climate change and growing population
How can people improve food supply by Improving agricultural productivity through technology
-Green revolutions since 1960 have introduced new crop varieties with higher yields, more mechanisation, better irrigation techniques, and new fertilisers and pesticides
Global rice yields have tripled since 1961, grain yields increased by 160%
-Development of hydroponics to allow food to be grown in new places
-Genetic modification of plants to make them more resistant to drought, pests and disease - golden rice
-Sustainable farming practices introduced and encouraged by NGOs and governments to improve longevity of food supply in vulnerable areas
How can Reducing food consumption and waste improve food security
-Improving storage, packaging and refrigeration facilities to make food last longer
-Educating farmers about crop loss prevention
-Encouraging consumers to cook and buy only what they need and to donate leftovers to food banks
-Better education about diet to tackle growing obesity crisis in the developed world
How can we increase access to food
-Free and fair trade rules to allow poorer countries to import food at fair prices
-Improving infrastructure to allow food to be transported to markets more efficiently and cheaply
How can organisations improve food security
-Social protection measures from governments and NGOs to reduce food poverty
-rants and food vouchers to vulnerable households
Free school meals for the most disadvantaged children
How do the global agriculture and food security program help people
Programme in Rwanda increased yields by 30% by teaching farmers sustainable techniques such as crop drying and compost
What is mortality
To do with death and dying
What is morbidity
The rate of disease in a population
Why do mortality rates vary
-In less developed countries this is due to poor socio-economic resources leading to lower life expectancy
-In developed countries this is due to higher life expectancies leading to ageing populations
-Infant mortality, case mortality and attack rate tend to be higher in developing countries with the highest rates generally in sub-Saharan Africa
What is healthy life expectancy (HALE)
refers to how long a person can be expected to live in good health without significant disease or injury, (used by the world health organisation)
