Human Impact on Biomes

Human Alterations to Biomes

• Humans have significantly altered the world's biomes, seeking food, water, and shelter and controlling nature since early civilization.
• Key human traits that contribute to biome alteration are control over nature, prioritizing human needs, and using technology for environmental control.

Why Biomes Are Altered

• Civilizations expanded through agriculture, requiring more land as populations grew.
• Industrialization increased the demand for natural resources, affecting various biomes.

Ways Humans Alter Biomes

• Vegetation clearing for agriculture, settlements, and infrastructure is a major cause of biome destruction.
• Temperate grasslands are heavily altered for agriculture.
• Deforestation has cleared 80% of the original forest cover, leading to habitat loss, especially in rainforests, reducing koala populations in Queensland due to land clearing.

Extent of Human Control

• Direct physical control involves trimming, pruning, weeding, and harvesting plants or animals.
• Chemical control uses chemicals to kill pests or promote growth.
• Habitat control includes modifying soil, draining swamps, or introducing/excluding species.
• Biological control introduces predators or diseases to control pests.
• Genetic control involves breeding organisms for specific traits.
• Behavior control includes training animals for specific behaviors.

Human Influence on Different Biomes

• Tropical rainforests face large impacts from timber cutting, farming, and urbanization.
• Temperate forests are cleared for crops, grazing, and development.
• Savanna and grasslands are cleared for agriculture and livestock, leading to erosion.
• Deserts experience minimal impact, except for agricultural expansion.
• Tundra and polar regions have less direct impact but are affected by pollution and fishing.

Water Cycle Control

• Water is vital for agriculture, industry, and urban living.
• There are 40,000 large dams worldwide, blocking rivers and altering ecosystems.
• Canals and pipelines are used to transport water.
• Groundwater extraction can lead to the depletion of resources.

Terracing and Soil Erosion in Australia

• Terracing is an ancient farming technique to reduce slope steepness, still used in China, the Philippines, and Bali.
• Forests covered 10% of Australia, and woodlands covered 23% when the British arrived in 1788; today, forest cover has been significantly reduced.
• Deforestation has resulted in the loss of 50% of eucalypt forests and 75% of rainforests, with over 35% of woodlands cleared or modified.
• Forests continue to disappear at a rate of 1% annually; some regions, like south-east Queensland, have a higher rate than the Amazon Basin.

Erosion Causes and Impact

• Water erosion is the most common type of soil degradation in Australia, caused by heavy rainfall or running water.
• Sheet erosion occurs when water evenly strips away soil across large areas.
• Rill and gully erosion happens when water creates small channels (rills) and larger channels (gullies) that carry away soil.
• Eroded soil is carried away by water, eventually clogging rivers and lakes, reducing water quality and shortening the lifespan of dams.
• Erosion contributes to the formation of saline soils and poor conditions for agriculture.

Wind Erosion and Prevention

• Wind erosion occurs when soil particles are blown away by the wind, particularly in dry areas with sandy soil.
• Regions most affected include areas with low rainfall, such as the outback and parts of central Australia.
• Minimizing bare soil reduces the time soil is left exposed to wind or rain.
• Vegetation management maintains plant cover by reducing grazing animals and eliminating pests like rabbits.
• Soil management includes building contour banks on slopes to control water flow, ploughing across slopes to prevent water runoff, and planting windbreaks with trees.

Land Clearing, Salinity, and Slope Management

• Land clearing can lead to rising water tables that bring salts to the surface, damaging the soil and vegetation.
• Well-managed slopes with vegetation help keep groundwater levels in check and prevent salinity.

Issues That Affect Food Production and Food Security

• Food security is when everyone always has access to enough safe, nutritious food to meet dietary needs and live a healthy life.
• Food supplies can be impacted by adverse weather, natural hazards, conflict, population growth, environmental degradation, trade barriers, and societal inequalities.
• A balanced diet requires diverse food types to ensure proper growth, development, and health, along with proper storage and hygienic preparation.
• Despite sufficient global food production, one billion people are still undernourished, mainly due to poverty.
• Concerns persist about future food shortages causing instability and disruptions, particularly in the poorest regions.

Increasing Demand for Food

-The global population continues to grow by about 100 million people annually, expected to reach 9.1 billion by 2050.

• As people exit poverty, their diets improve, increasing the demand for protein-rich foods (meat and dairy).

Limitations on Food Production

• The rate of increase in global grain crop yields has slowed from 5-10% annually to just 1% annually.
• Land used for food production is diverted for purposes such as livestock feed, biofuels, and urban expansion.

Globalization and Water Shortages

• Food has become a commodity driven by large agribusinesses, disadvantaging small-scale farmers.
• International trade in food products is growing, but trade restrictions impact poorer countries, hindering food access.
• Water is essential for food production, and overuse of water resources contributes to shortages.

Declining Water Quality and Climate Change

• Declining water quality and availability pose significant risks to agriculture and global food security.
• Climate change exacerbates food security issues by altering temperatures, rainfall patterns, and increasing the frequency of extreme weather events.

Multidimensional Food Security

• Food security is multifaceted, encompassing availability, affordability, and nutritional quality.
• The poorest are most vulnerable to food shortages, lacking resources to secure food during crises.
• Global food production faces pressure from rising demand, limited land and water resources, and environmental changes.

Population Growth and Water Usage

• Population growth, climate change, and armed conflict are of major consideration.
• Water is essential for all food sources, including crops, livestock, aquaculture, and inland fisheries.
• Water scarcity is growing, stressing key food-producing systems due to high demand for water from surface and groundwater.
• Agriculture consumes 85% of the world's freshwater.
• Producing food requires varying amounts of water; 3400 liters to produce 1 kilogram of rice.

Rain-fed, Irrigated Agriculture, and Water Scarcity

• Over 80% of cultivated land relies on rainfall and soil moisture; erratic rainfall can cause crop yield reduction.
• Smallholders in arid and semi-arid regions, are most affected by rainfall deficiencies.
• Irrigation increases crop yields by 100-400% and provides 40% of the world's food using only 20% of the cropland.
• Water scarcity is caused by shortages of freshwater and is severe in marginal areas.
• Excessive water withdrawal leads to the depletion of groundwater and river levels.

Threats and Pollution

• Depleting groundwater threatens food production in regions like China's North Plain and Australia's Murray-Darling Basin.
• By 2025, 1.8 billion people will face scarcity two-thirds of the population will face water-stressed conditions.
• Agricultural practices pollute water through excess nutrients from over-fertilization, pesticides, and toxic algal blooms, making water unusable for food production.

Key Points on Food Production

• Water is vital for food production, and scarcity is a growing global issue.

Patterns of Population Growth

• Over the last 200 years, rapid population increase, expansion of settlements opening new land, development of modern agriculture, sanitation, and medical advances has grown the Earth’s population.
• More people means more mouths to feed, though food security is especially challenged in areas with the highest population growth rates.
• Most poor and hungry people live in rural areas now, more people are moving to cities.
• As people move to cities, food consumption patterns change, and there is an increasing demand for processed foods.

Population Growth in Developed Nations

• Almost all future population growth will occur in developing countries.

Climate Change and Farming

• Climate affects all aspects of food production, influencing what can be grown, where can be grown, the quality of the produce, and most importantly, the yield.
• Climate change is expected to alter the nature and amount of food produced.
• Greenhouse gases (carbon dioxide, methane, nitrous oxide) are rising due to human activity, leading to global warming.

Food Production

• Increased extreme weather events and greater climate variability are likely to decrease food productivity.
• If global temperatures rise by more than 2.7°C, rain-fed agriculture could see halved yields by 2020 due to prolonged droughts.

Winners and Losers of Climate Change

• Rising carbon dioxide could slightly boost crop productivity in middle to high latitudes.
• In the Northern Hemisphere, areas like Russia and Canada could benefit from longer growing seasons and more precipitation, increasing cereal production.
• The Southern Hemisphere, particularly developing countries in Sub-Saharan Africa, will likely suffer the most from extreme weather (droughts, floods).

Armed Conflict and Farmland Destruction

• During wars, farms and crops can be destroyed by bombing, fighting, or even deliberate acts like landmines, leaving farmers with no land to grow food.
• Many farmers are forced to flee their homes to escape violence, impacting crop production.

Disrupted Supply Chains and Limited Access to Water

• War often breaks roads, bridges, and transportation networks, making it hard to get seeds, fertilizers, and other farming tools to farmers.
• It prevents food from reaching markets, making it harder for people to access what little food is available.
• Conflicts often disrupt access to water for irrigation, and damaged infrastructure makes it difficult to transport water for farming.

Economic Instability and Climate Change

• Wars can destroy economies, making it harder for farmers to buy equipment or even sell their crops, leading to higher food prices and lower availability.
• Uncertainty caused by conflict prevents people from making long-term investments in farming, like planting crops that take months to grow.

Green Revolution

• The Green Revolution started in Mexico (1943) to improve wheat production.
• High-yield crop varieties (wheat, maize, rice) were introduced, helping countries become self-sufficient in food production.

Innovations of the Green Revolution

• Focused on tropical crops and introduced dwarf plants (short, strong stalks).
• Multiple cropping (several harvests per year) was used.

Fertilizers and Chemicals

• The purpose of these were to increase crop yields, though overuse of fertilizers (nitrates & phosphates) leads to water pollution.
• Agrochemicals (e.g., DDT, PCBs) build up in food chains, damaging human health.

Fossil Fuels in Agriculture

• Fossil fuels are used for producing & applying fertilizers, pesticides, pumping irrigation water, and running machinery (tractors, harvests, etc.).
• But heavy reliance on oil makes agriculture unsustainable, contributing to greenhouse gas emissions and climate change.

Changing Diets

• Increased grain production could feed more people, instead grain is used for livestock feed (as meat demand rises).
• Biofuel production (for cars), reducing food availability.

Negatives of the Green Revolution

• Environmental Damage Heavy use of chemical fertilizers and pesticides led to soil degradation, water pollution, and loss of biodiversity.
• Farmers became reliant on expensive fertilizers and pesticides, which can harm the environment and human health.
• Wealth Gap - Large, wealthy farmers benefited more than small-scale farmers, leading to economic inequality.

Gene Revolution

• Scientists use genetic engineering to transfer desirable traits between species
• Supporters believe it could end global food shortages.
• Critics worry about unknown long-term health & environmental risks.

Factors of Argiculture

• The three factors of agriculture
• Environmental
• Economics
• Technological