Increased awareness about environmental issues including global warming, deforestation, pollution etc have resulted not only in depth analysis of these issues but also motivated the researchers to devise methods to quantify the services provided by the nature. In contrast to economic indicator or GDP , the latest tools for measuring ecological values of various services have facilitated to accord more priority to the environmental sector for policy makers and administrators to tune their interventions in order to make them more sustainable and eco friendly.
These two measures are Ecological footprint and Bio- capacity and also called as "EF" and "BC" in short.
The ecological footprint(EF) is a measure of the load imposed by a given population on nature. In other words it is the area of the earth which is required to meet the levels of resource consumption on sustainable basis including waste discharge by that population.
Bio-capacity (BC) in simple words means the biological productive capacity of a resource. (e.g. agriculture land, pasture, forest, productive sea).
Both the Ecological Footprint and bio-capacity are measured in terms of global hectares (g ha), which represent a hectare of land with average productive bio-capacity.
In other words EF and BC are equivalent to the economic concepts of demand and supply. When used together, they form the EF/BC accounts. EF/BC accounting is frequently referred to only as EF accounting.
The EF/BC accounts are formed by combining the EF and the BC, thereby turning the approach into a more complete accounting tool for natural resources. The algebraic difference between BC and EF is called Ecological Deficit, if it is negative or Ecological Reserve if it is positive.
In 2008, the Earth’s total bio-capacity was 12.0 billion gha, or 1.8 gha per person, while humanity’s Ecological Footprint was 18.2 billion gha, or 2.7 gha per person. This discrepancy means it would take 1.5 years for the Earth to fully regenerate the renewable resources that people used in one year.
Global Foot Print networks has assessed the trends in Ecological foot print and bio capacity per person between 1961 & 2008 which is shown below.
The major issues concerning both the EF and BC are that while the increasing GHG emissions and other environmental problems causing increasing global temperatures, climate change, land degradation and ocean acidification putting enormous stresses on biodiversity and ecosystems. This affects the bio-capacity of the earth very badly. Same time the increased exploitation of resources for burgeoning population is increasing the EF at an unprecedented rate. The more is the gap between the EF and BC ,more we are near to exhausting our resources and collapse of ecosystems due to this overshoot i.e., shortfall in earth’s biological capacity to meet the consumption demands of all humanity.