How Precisely «Kaya Identity» Can Estimate GHG Emissions: A Global Review

Climate change is the greatest environmental threat facing our planet, endangering health, communities, economy and national security. Many models tried to evaluate influencing factors, estimate emission rates or any parameter can effect on this phenomena. «Kaya identity» is a mathematical equation that relates economic, demographic and environmental factors to estimate anthropogenic emissions in global scale. In the present study, «Kaya identity» is developed for 215 countries around the world (national scale) during 1990-2011. Then model predictions are compared with real data to evaluate how well Kaya identity can estimate emissions and how results accuracy changed over time. Based on the results, energy intensity and carbon intensity follow a decline; population and Gross Domestic Product (GDP) per capita follow an increasing path. More than 80% of emissions, about 74% of GDP and 52% of the population around the world can be estimated precisely ( 20% error) by Kaya identity. The model predictions show an improvement in accuracy of results over time. Eight out of top ten emitter countries could be estimated well (usually between -20% error +20%) by Kaya identity from emission point of view. Results confirm that Kaya identity can be used widely and reliably for estimation of emissions and identification of effective factors globally to help in achieving emission reduction targets by helping governments to better predict emission rates.