Impact of Increasing Demand for Food, Fuel & Other Resources
Growing Resource Demands
- The biosphere sequesters about one quarter of fossil fuel carbon emissions every year, slowing down the rate of global warming
- However, the biosphere’s capacity to sequester carbon dioxide is being reduced due to land conversion
- Land conversion is being driven by an increasing demand for food, fuel and other resources
Deforestation
- Forests cover 30% of the Earth’s land area and absorb rainfall and increase groundwater storage
- Deforestation occurs for either the timber or the space they occupy and is driven by the increasing demand for commodity production
- An estimated 10 million hectares are deforested every year
- Deforestation has impacts on the water cycle:
- Reduced interception by vegetation so infiltration to soil and groundwater changes
- Increased erosion and surface run-off, increasing sediment eroded and transported into rivers
- Deforestation has impacts on the carbon cycle:
- Reduced storage in soil and biomass
- Reduced carbon dioxide intake during photosynthesis
- Increased carbon influx to atmosphere by burning and decomposing vegetation
Afforestation
- Afforestation and reforestation are beneficial for carbon dioxide sequestration but can be controversial in its impacts:
- Commercial trees such as palm oil often store less carbon, use more water and are prone to disease
Grassland Conversion
- There are two main types of grassland which cover 26% of the Earth’s land area
- Temperate grassland - no trees and a seasonal growth pattern linked to a large annual temperature range e.g. North America
- Tropical grassland or Savannah- scattered trees with a wet and dry season e.g. Africa’s serengeti
- When grasslands are used too intensively for animals or agriculture it disrupts the carbon and water cycles
- Rapid increase in population and changes from nomadic to sedentary farming along with the impacts of climate change and poor land management
- Soil and ecosystem degradation is now becoming a worldwide issue which is leading to a loss in carbon storage
Exam Tip
Make sure you are able to explain how land conversion affects global warming. Remember land conversion is the clearing of land (ecosystems) to use the land for a different purpose