Calculadora Kaya Identity
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
CO₂ = P × (PIB/P) × (E/PIB) × (CO₂/E)
About this calculator
The Kaya Identity Calculator decomposes total CO₂ emissions into four factors: population (P), GDP per capita (GDP/P), energy intensity of GDP (E/GDP), and carbon intensity of energy (CO₂/E). The formula is CO₂ = P × (GDP/P) × (E/GDP) × (CO₂/E). Proposed by Japanese economist Yoichi Kaya, this identity helps understand how each factor contributes to total emissions, enabling scenario analysis and climate policy evaluation.
To use the calculator, input values for the four factors. The result shows the total CO₂ emitted. It is useful for students, researchers, and policymakers who want to simulate the impact of demographic, economic, and technological changes on emissions. For example, increasing energy efficiency (reducing E/GDP) or decarbonizing the energy mix (reducing CO₂/E) shows the effect on the total.
Caveats: data must be consistent (same time unit, inflation-adjusted currency). The identity is an accounting decomposition, not a causal model. It does not consider feedbacks between factors (e.g., population growth may affect GDP). Use it as an exploratory tool, not for precise predictions.
Frequently asked questions
What units should I use for each factor?
Use consistent units: population in number of people, GDP in constant currency (e.g., 2010 dollars), energy in joules or tons of oil equivalent, CO₂ in tons. The result will be in the chosen CO₂ unit.
Can the Kaya identity predict future emissions?
Not directly. It shows how emissions decompose, but does not model relationships between factors. For predictions, you need to project each factor separately using economic and demographic models.
How is energy intensity (E/GDP) calculated?
It is the amount of energy consumed per unit of GDP. Lower values indicate a more energy-efficient economy. It can be reduced through better technology or structural changes.
What does carbon intensity (CO₂/E) mean?
It is the amount of CO₂ emitted per unit of energy consumed. It reflects the energy mix: fossil fuels have high intensity; renewables and nuclear have low or zero intensity.