UNIT 4: Agriculture and Climate Change

Success Criteria

• Define climate change.
• List causes of climate change.
• Discuss the effects of climate change on land, crops, livestock, and livelihood.

Climate Change: A Professional Summary

Climate change refers to significant and long-term shifts in global or regional climatic conditions, encompassing changes in temperature (manifested as global warming or cooling), precipitation patterns, and wind patterns over extended periods.

Causes of Climate Change

Climate change stems from both natural processes and human activities.

Natural Causes:

• Volcanic Gases: Eruptions release gases like sulfur dioxide, contributing to phenomena such as acid rain.
• Plate Tectonics and Continental Drift: The slow movement of Earth’s landmasses shifts continents into different latitudinal zones, thereby altering regional climatic conditions over geological timescales.
• Shifting of the Earth’s Orbit: Variations in Earth’s orbit around the sun can influence the amount of solar radiation received, leading to long-term climate fluctuations.

Human (Anthropogenic) Causes:

• Carbon Dioxide Emissions:
  • Transportation: Exhaust from vehicles and other locomotives.
  • Burning of Fossil Fuels: Combustion of coal, oil, and natural gas releases vast amounts of carbon dioxide into the atmosphere. This greenhouse gas absorbs and retains heat from the sun, leading to increased atmospheric temperatures (global warming).
• Extensive Bushfires: Large-scale and uncontrolled burning of vegetation releases significant carbon into the atmosphere and destroys carbon sinks.
• Increased Agricultural Activities:
  • Deforestation for Farmland: Clearing vegetation to create new agricultural land reduces the planet’s capacity to absorb carbon dioxide.
  • Livestock Methane Emissions: A growing cattle population leads to increased dung deposits, which decompose to produce methane, a potent greenhouse gas.
• Urbanization:
  • Forest Clearing: Forest land is often cleared for human settlements and industrial development.
  • Concrete Surfaces: Replaced natural surfaces absorb more solar heat, contributing to higher local and atmospheric temperatures.
• Rapid Population Growth: An expanding global population increases demand for forest and land resources, leading to accelerated deforestation, which in turn contributes to global warming and drought by reducing transpiration (release of water vapor into the air by vegetation).
• Release of Chlorofluorocarbons (CFCs): These synthetic gases contribute to the depletion of the stratospheric ozone layer, which protects Earth from harmful ultraviolet radiation, indirectly impacting atmospheric heat dynamics.

Effects of Climate Change on Land, Crops, Livestock, and Livelihood

Climate change has far-reaching and detrimental effects across various sectors:

• Crop Failure and Food Insecurity:
  • Increased frequency and intensity of floods destroy crops and agricultural infrastructure.
  • Prolonged droughts lead to widespread crop failure, significantly decreasing food production and causing severe food insecurity.
  • Shifting rainfall patterns result in unpredictable heavy rains or prolonged dry spells, disrupting traditional farming calendars.
• Impact on Land and Water Resources:
  • Desertification: Depletion of underground and surface water resources due to reduced infiltration and increased evaporation in desertified areas.
  • Increased Sea Levels and Coastal Flooding: Global warming causes the melting of glaciers (large masses of ice sliding down mountain slopes) and ice sheets in the Arctic and Antarctic regions. This influx of freshwater raises ocean levels, leading to widespread flooding in coastal areas, threatening land and infrastructure.
• Biodiversity Loss and Ecosystem Alteration:
  • Extinction of Species: Harsh temperatures and altered habitats lead to the extinction of plant and animal species.
  • Altered Ecological Balance: Changes in ecosystems disrupt natural processes and relationships between species.
  • Loss of Biodiversity: Plants and animals die or migrate from areas experiencing drought conditions or extreme temperatures, leading to a reduction in overall biodiversity.
• Increased Adverse Weather Events: More frequent and intense storms (e.g., hurricanes, cyclones) cause extensive damage to crops and infrastructure.
• Disease Outbreak: Higher temperatures promote the multiplication and spread of disease-causing organisms and vectors, such as mosquitoes that transmit malaria, leading to increased disease incidence.