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Pop & Env, Majority of world will suffer from yield declines.
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Pop & Env
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Population Ecology
Study of how environment affects pop factors:
- Size
Distribution
- Density
- Age-sex composition
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- Rely on environment & resources to survive
Carrying capacity:
- Maximum pop that can be supported without environment being severely degraded
- If pop reaches this -> resources no longer available to support -> increase DR & fall in BR until pop can be supported
Ecological Footprint:
- Measurement of how much of Earth's resources are used in relation to amount of Earth's resources available
- Ecological footprint measured in global hectares. If over 1, consumption larger than available on Earth
Implications:
- Climate change, exacerbation of global warming
- more land taken for settlement, industry & transport
- Degradation of natural ecosystems
- Increased threat of species extinctions
- over-cultivation & overgrazing reducing land & soil quality
Population, Resources & Pollution Model:
- Shows relationship between it
- Positive & negative feedback loops created to form relationships
- Pop needs to acquire & use resources to grow -> creates pollution -> impacts pop
Population Perspectives
Malthus:
- Pop increases exponentially, resources increase linearly -> pop eventually run out of feed & resources & decrease as result.
- Pop will decrease -> positive & preventative checks when pop -> too high
Positive checks: disease, war, famine -> disaster to reduce pop
Preventative check: cultural choice to lower pop -> choosing not to have children
Boserup - non malthusian perspective:
- No matter how large pop grows, pop will always discover new ways to sustain food supplies. E.g. new technologies
Soil Problems
Soil erosion
Wearing away of soil, especially topsoil -> responsible for providing nutrients & structure for agricultural activity.
Water Erosion:
- Degradation & wearing away of soil due to water
- Occur -> climatic factors, interception of plants, topography
- Agricultural practices can contribute to water erosion; poor irrigation
Sheet erosion:
- washing away of soil in uniform manner, leading to widespread removal of topsoil.
- Heavy rainfall & flooding can cause a 'sheet' of water to wash over an area, displacing soil & nutrients
Rills & Gullies:
- Rills = small streams that develop by erosional flowing water. Often develop on slopes.
- Rills can develop into gullies, large amounts of soil & nutrients washed away, leaving permanently damaged landscape
- This process exacerbated by agriculture, as fields empty of crops & plants or trees allow for streams to develop
Riverbank erosion:
- Degradation of riverbank sides, large sections of bank to erode
Issues for agriculture:
- Soil washed away, causes crops to become unstable & crops may be washed away
- Nutrients leaches away into lower parts of soil
- Weeds spread from other areas if carried in water
- Rills & gullies can obstruct farming equipem
Wind Erosion:
- Winds blow away topsoil
- Prevalent in dry climates, soil particles = less cohesive -> unstable topsoil
- Areas of agricultural land = more vulnerable to wind erosion -> practices such as ploughing & tilling loosen soil particles
- Overgrazing or clearing land for crops causes soil particles to become less bound together
Differs by size of soil particles that are transported
- Larger soil particles are heavier, cannot be transported as freely as small particles
- Roll along floor by creep, bounce by saltation, suspended in air
Issues for agriculture:
- Most fertile topsoil blown away, leaving crops with less nutrients for growth
- Crops can become buried in thin soil layers after high winds -> damage crops & restrict sunlight
- Wind erosion lowers soil capacity to store water -> depth of soil reduced, soil becomes drier
Structural deterioration is the loss of the structure of the soil, esp pores between soil particles that contain air.
Structural deterioration may occur:
- Livestock can trample on ground -> compacts soil & removes the natural spaces between particles
- Crops & plants roots give structure to soil, removing these for agriculture or harvests can disrupt structure
- Farming machinery -> soil compaction, removing air spaces in ground
Issues for agriculture:
- Water can't infiltrate due to lack of space in soil -> plants become dehydrated
- Root cells need air to survive. This removes air pockets & suffocates roots
- Root growth may become obstructed as roots can't infiltrate compacted soil
- Soil is harder work with when structure deteriorates -> harder to plough or till
Issues on agriculture:
- Limited oxygen supply in soil, restricting plants respiration & causing them to drown
- Roots may rot in stagnant water, killing plant or stunting growth
- Can leach away minerals for plant growth, bring unwanted minerals to topsoil e.g. salts
- Water lowers temp of soils -> slows photosynthesis
Water-logging:
- When soil becomes oversaturated with water that there is no longer O2 present -> plants can't respire aerobically
- Can occur due to structural deterioration & too much irrigation
Salinisation:
- increase of salt content in soil, -> crust of salt on topsoil
- Occurs when saline water rises to surface of soil & water evaporates -> salt concentrated in topsoil
- High temps draw saline soil water to upper parts of soil
- Dry climates heighten process as salts can't be leached away by precipitation
- Groundwater levels rise, salts from lower levels of soils are brought upwards
Issues on agriculture:
- Salts = toxic to plants -> reduce fertility of plants, reduce yields & kill them
- High salt contents effect how plants absorb water. Water moves through osmosis. When salt content = high, osmosis can't happen -> dehydrate plants
- may break up natural soil structure, affecting plant growth & productivity
Desertification:
- Fertile land becomes dry, cracked & desert-like -> unproductive land
- Caused by climate, little precipitation & high temps -> dry soil out
- Overgrazing & over cultivation deplete nutrients in soil & break down structure
- Irrigation may drain underground water stores or cause salinisation -> desertification
Issues on agriculture:
- Plants can't grow in dry, compact, eroded, structurally degraded soils
Management of Soil Problems:
- Salinisation & desertification are difficult & expensive to reverse -> preventing is more effective
Efficient irrigation & drainage:
- Water-logging, water erosion & salinisation -> water surplus
- Drip irrigation -> avoid overwatering. Agricultural areas can use drainage methods -> underground drainage systems
Runoff can be redirected:
- Contour ploughing, obstructs water from flowing downhill
- Terracing, steps carved into hillside to spread out water levels rather than flowing downhill
- Diversion channels, runoff flows in channels with quickest route, redirecting away from crops
Moving Livestock:
- Regularly, ensures ground not trampled extensively -> limits structural deterioration
- Avoids overgrazing, plants can keep structure of soil intact : :
Changing Soil Composition:
- Altering composition of soil limits wind erosion & structural deterioration, adding certain materials can encourage well binded soil with natural pores
- Adding mulch to soils protects small soil particles from wind erosion, binds soil together
- adding sand to clay soils can stop them clumping & deteriorating
Multiple cropping:
- Planting more than one crop in agricultural area
- Stops nutrients being overexploited, maintains soil quality
- Monoculture depleted certain nutrients from soil -> poor soil quality & structural deterioration
- Multiple crops provide more fertile & healthy soil
Cover crops:
- Planted for maintaining soil quality
- Crop used to cover bare field, less vulnerable to soil issues -> erosion
- Maintain structure of soil, plants hold together with roots, take up soil water & protect soil particles from wind & rain
- Water-logging, water erosion wind erosion & structural deterioration may be prevented
Windbreaks:
- Bushes, trees, man mad -> netting -> obstruct winds
- Can limit wind erosion on arable land, yielding higher productivity
Food Security
Having available, accessible & affordable food that is safe & nutritious, so people may live a healthy lifestyle
Strategies to Ensure Food Security:
Increasing access -
- Increasing access to foreign markets means they can import food, increasing food security
- Trading agreements -> trade blocs, beneficial to country struggling to provide enough food for pop
- Times food security = dangerously limited, e.g. after crisis or natural disaster, aid & relief can also increase food security
Increasing amount -
- Strategies & new tech can increase amount being produced -> increases food security -> more available food & healthier
- Managing farms more successfully through training, farming equipment & high yielding varieties -> increase food supplies
- Country has more food available to distribute to pop
Increasing efficiency -
- Save time & food -> overall, more food available & may be more affordable -> less expenditures
- Equipment & better management can produce more crops in less time -> affordability & food availability
Green Revolution:
- Tech increased food security by increasing amount of food & efficiency of farm - specifically developing regions
- Increased use of fertilisers/pesticides, mechanisation, irrigation & development of high yielding varieties. Increased yields areas such as India
- Responsible for increased calorie intake in LICs -> thought to have raised grain yields by 160%
- Issues associated with revolution, salinisation caused irrigation, farmers unable to repay loans on expensive equipment
Global Agriculture & Food Security Program:
- Believe the world need to produce about 56% more food by 2050 to feed everyone
- Mission is to strengthen resilient & sustainable agricultural systems in LICs by investing in smallholder farmers & their communities
- Receive donations from wealthy governments, these donations allocate funding where it is most needed
- Increase livestock & pasture productivity
- Improve crop breeding
- Plant existing cropland more frequently
- Increase fish supplies
Natural Population Chang
Birth rate: Number of live birther per 1000 of pop per year
Death (mortality) rate: Number of deaths per 1000 of pop per year
Infant mortality rate: Number of deaths of infants under 1 per 1000 of live births per year
- Total fertility rate: Average number of children a mother will birth in her reproductive age
- Pop growth rate: % change. If birth rates exceed death rates % change is positive if DR exceed BR, % change = negative
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- Age & sex = major demographic variables in pop.
- Indicate country's development
- can be shown on Pop pyramids
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Agriculture
Agricultural Systems
Produces yields = agriculture classed as system -> inputs, processes & outputs.
Physical inputs:
- Climatic factors - sun & rain
- Soil - mineral content, saturation
- Location
- Pollination
Human inputs:
- Farming machinery - maintenance & harvesting
- Fertilisers & pesticides
- Seeds & livestock
Labour
Processes:
Arable farming -
- Planting seeds
- Tending to land
- harvesting
Pastoral farming -
- Tending to livestock
- Breeding
- Collecting produce
Outputs:
- Food crops
- Crops -> cotton, silk
- Animal produce
- Products to sell & trade
Losses & outputs:
- Losses in natural hazards, droughts & floods
- Waste e.g. manure
- Unused, wasted food
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Farming strategies
Climate Smart Agriculture 2012:
Integrated approach to address the interlinked challenges related to food security & climate change through:
- increased productivity (economic) - improve food & nutrition security & boost the incomes of world's rural poor who rely on agriculture
- enhanced resilience (social) - to reduce vulnerability to drought, pests & disease & improve capacity to adapt to challenges such as shortened seasons or erratic weather patterns
- reduced emissions (environmental) - to pursue lower emissions for each unit of food produced & reduce/remove greenhouse gas emissions from agriculture, including avoiding deforestation
Indian Agricultural Research Institute:
- Carried Climate Change Adaptation Projects to test technologies & strategies for sustainable livelihood security in rural communities that are vulnerable to climate risks
- Mewat district > drought- prone area
- Recently experienced unseasonal hailstorms & extreme rainfall patterns, used to occur every 10 years
- Storm events negatively impacted farmers & production
- IRAI developed a customised set of interventions to converse resources, adapt to climate changes & improve livelihoods:
- Superior seed varieties were tested & successful ones were made available through village seed banks
- Heat -stress tolerant varieties of the major crop, wheat, were introduced, increasing yields by 12 to 18%
- Farmland was levelled using lasers. This improved water-use efficiency by about 15 to 20%
- Underground pipelines used for delivering high-tech drip irrigation; resulted in additional 45%
- Greater cop diversification introduced with high yielding varieties
Global Patterns of Health, Mortality & Morbidity
- Mortality rates vary throughout world, & provide indication of socioeconomic status of a region/country.
- Infant mortality = indicator of mortality & socioeconomics of a region
Morbidity:
- Morbidity rates are shown through incidence of diseases. Usually influenced by lifestyle choices
- Non-communicable diseases higher in HICs, -> infectious diseases or biologically transmitted diseases more prevalent in LICs.
Mortality rate of a disease is dependent on ability to treat morbidity.
- Mortality rates lower than morbidity rates as people can be treated. However, the
- Proportion of those who die from disease they have contracted is higher in LICs than HICs.
- Health better in HICS, = demonstrated by the morbidity rates of certain diseases in HICs compared to LICs. Another i
- Indicator of health = life expectancy, higher in HICs. HICs usually spend more money on health, which often correlates to the higher life expectancy.
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Population Parameters
Parameter = a measurable factor. Pop parameter = different ways in which the population is measured. Useful to gain insight into the characteristics of a pop.
- Distribution
- Density
- Numbers
- Change
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Majority of world will suffer from yield declines.
- Increase in extreme weather events is likely to decrease productivity
- Temperature rises & precipitation changes also cause agricultural land to decrease in areas
- Temperatures are rising & rainfall is becoming more scarce & unpredictable in areas prone to drought
- Soil problems -> erosion, desertification, salinisation are projected to increase in some areas due to higher temperatures -> arable land unusable
- Melting ice -> rising sea levels -> flooding
- Pests insects & plant diseases projected to increase in areas.