IB Environmental systems and societies 1.3F Sustainability Indicators Notes

Sustainability indicators are measurable variables that reveal whether human use of the environment can continue without long-term harm

1. They show whether current practices are sustainable or whether adjustments are needed for long-term balance.
2. They can be applied at a local scale or a global scale.

The four categories of sustainability indicator

1. Biodiversity: measures how varied and abundant species are, since higher diversity usually means greater resilience.
2. Pollution: shows where and how severely pollution is occurring, often using indicator species.
3. Climate: tracks long-term change through variables such as CO2 concentration and temperature.
4. Demographic: links human population growth to rising resource demand.

Biodiversity indicators

1. Species richness counts how many different species are present.
2. Simpson's reciprocal diversity index gives a single number for diversity, and is only meaningful when comparing sites or times.

Pollution indicators

1. Indicator species are organisms that react predictably to pollution, so their presence or absence reveals pollutant levels.
2. A biotic index uses aquatic organisms to infer water quality.
3. Biochemical oxygen demand (BOD) measures organic pollution indirectly, since high BOD shows heavy oxygen demand from decomposing waste.

Climate indicators

1. They are based on long-term records of change in climate systems.
   1. Mean global temperature tracks warming.
   2. Atmospheric CO2 concentration tracks the driver of the enhanced greenhouse effect.
   3. Ocean pH tracks acidification.
   4. Sea-level rise tracks thermal expansion and ice melt.
2. Together they show the direction and pace of environmental change.

Demographic indicators

1. Population growth rate links population size to rising resource demand.
2. Urbanisation rate tracks the share of people living in cities.