Humans and biodiversity

• Global warming


  The gradual increase in the average temperature of the Earth
• Levels of carbon dioxide and methane in the atmosphere are increasing due to human activity, contributing to global warming and climate change
• This scientific consensus is based on systematic reviews of thousands of peer-reviewed publications
• Global warming has resulted in large-scale habitat change and reduction, causing a decrease in biodiversity, extreme weather and sea level changes, migration of species to different parts of the world, affecting ecosystems, and threats to the security and availability of food
• Land use and deforestation

  Rapid growth of the human population and increases in the standard of living mean that humans are using more resources and producing more waste
• Waste and chemical materials need to be properly handled in order to reduce the amount of pollution they cause, Pollution kills plants and animals, and can accumulate in food chains, reducing biodiversity
• Pollution can occur


  • in water, from sewage, fertiliser run-off, or toxic chemicals (eg, from factories)
  • in air, from smoke and acidic gases
  • on land, from landfill and toxic chemicals
• Rapid population growth has led to humans using much more land for building, quarrying, farming, and dumping waste. This reduces the area in which animals can live and can further destroy habitats through pollution
• Large-scale deforestation in tropical areas has been carried out to provide land for cattle and rice fields, and to grow crops for biofuels. This has resulted in large amounts of carbon dioxide being released into the atmosphere due to burning of trees, extinctions and reductions in biodiversity as habitats are destroyed, and climate change, as trees absorb carbon dioxide and release water vapour
• Biodiversity


  The variety of all the different species of organisms (plant, animal, and microorganism) on Earth, or within a specific ecosystem
• High biodiversity


  • Ensures the stability of an ecosystem because it reduces the dependence of one species on another for food or habitat maintenance
  • The future of the human species depends on us maintaining a good level of biodiversity
• Many habitats are currently under threat due to changes caused by human activities, such as deforestation, climate change, and habitat destruction
• Ways scientists and concerned people are trying to maintain biodiversity and reduce the negative impact of humans on ecosystems

  • Breeding programmes in zoos for endangered species
  • Protection and regeneration of rare habitats (eg, national parks)
  • Reintroduction of hedgerows in agricultural areas where single crop species are grown, as hedges provide habitat for many organisms
  • Government policies to reduce deforestation and carbon dioxide emissions
  • Recycling resources rather than dumping waste in landfill