Revisiting Kaya Identity to define an Emissions Indicators Pyramid.

The impact of energy use on the planet due to related CO 2 emissions is continuously increasing, despite the adoption of efficiency and decarbonisation policies and widespread environmental awareness. Climate change mitigation will only succeed if the driving forces of consumption and emissions are deeply analysed, and effective means are provided to reverse their trends. To this aim, the Kaya Identity framework is revisited to classify indicators and decomposition studies in the literature. A comprehensive pyramid approach is proposed for the progressive disaggregation and discussion of energy and emissions changes. The approach is applied to the OECD and non-OECD to provide meaningful regional analysis of past trends and future projections according to stated policy intentions. Results show that a hopeful change has already begun in the developed region due to a sustained decrease of the energy intensity and a promising reduction of the carbon intensity. Emerging economies follow the performance of developed nations since 2013, held back by later economic development. Activity slowdown, energy conservation, renewable electrification, efficient power plants and coal phase out appear as the keystones for decarbonisation. As a result, emissions stabilisation could have already been achieved as rises in emerging countries are offset by drops in developed nations. However, more stringent climate policies, especially targeting carbon drivers, are urgently needed to enable emissions reductions compatible with a global temperature increase of 1.5°C. • Classification of indicators and studies in the framework of Kaya Identity. • Definition of an Emissions Indicators Pyramid for analyses standardisation. • Activity slowdown and cleaner electricity drive emissions drop in the OECD since 2007. • Hopeful efficiency and carbon intensity changes in developing nations since 2013. • Energy intensity must be halved and carbon intensity quartered in 2040. [ABSTRACT FROM AUTHOR]