CHAPTER 24 Summary

• Sustainability refers to the ability of humans to live within Earth’s biocapacity—its ability to provide current and future generations with natural resources and to absorb our wastes.
• Natural resources include nonrenewable resources such as fossil fuels (oil, coal, and gas) and renewable resources such as sunlight, wind, and water.
• Ecologists measure human demand on Earth’s resources using ecological footprint analysis, which quantifies the amount of biologically productive land and water needed to support our lifestyles.
• The ecological footprint of the current human population is greater than Earth’s biocapacity, which means that we are living unsustainably.
• The largest component of our footprint is burning fossil fuels, which generates harmful wastes, including greenhouse gases and pollutants.
• As the human population grows, so does our ecological footprint. As of 2012, the human population totaled 7 billion people. Some demographers predict the number could hit 9 billion by 2050.
• Freshwater is a renewable resource, but the world’s supply is not distributed equally, and many people around the world suffer from water scarcity, a problem exacerbated by a rising population, the demands of agriculture, and socioeconomic challenges.
• Sustainable practices minimize the consumption of nonrenewable resources by using renewable resources like wind and solar power instead of fossil fuels to generate electricity and heat.
• At their current level of development, technologies to harvest renewable energy cannot meet our total energy demands. Fossil fuels cannot yet be taken out of our energy mix.
• Individually, we can decrease our ecological footprint by driving less, reducing water and electricity use, consuming less meat, and recycling.

• MORE TO EXPLORE

  • National Renewable Energy Laboratory, Greensburg Deployment Project eere.energy.gov/deployment/greensburg.html
  • Global Footprint Network, Footprint Calculator www.footprintnetwork.org/en/index.php/GFN/page/calculators/
  • World Wildlife Fund (2012) Living Planet Report http://www.footprintnetwork.org images/uploads/LPR_2012.pdf
  • White, S. S. (2010) Out of the rubble and towards a sustainable future: the “greening” of Greensburg, Kansas. Sustainability 2:2302–2319.
  • Planet Green (Discovery Communications) (2010) Greensburg (documentary series).