Deciphering the global CO2 emissions target
A strong alignment exists between energy consumption and development. In countries with emerging economies, Gross Domestic Product (GDP) per capita and energy consumption per capita rise in unison. In more mature economies that are more service oriented, the relation between the two figures is weaker.
The Kaya Identity
The above trends can be linked to global CO2 emissions by the Kaya Identity, which breaks down global CO2 emissions into their main driving forces: CO2 = people x GDP/person x energy consumption/unit GDP x CO2/unit energy In the paper Pathways to 2050, the World Business Council for Sustainable Development (WBCSD) proposes setting the target of bringing CO2 emissions back to their 2002 level by 2050. Although this target does not sound very ambitious, the Kaya Identity shows how difficult it will be to reach it in a rapidly developing world.
A forecast for 2050
The forecast for population growth that is considered most likely is from 6 billion today to 9 billion in 2050. At the same time, the average GDP per capita is expected to grow from 7,000 US$ (in 2002) to 17,000 US$ in 2050. This means that, to reach the proposed CO2 emissions target, both energy consumption and CO2/unit energy must be cut in half. So by 2050, the world must generate a dollar of GDP with half of the energy, and a unit of energy must be generated with half of the carbon emissions as compared to 2002. 1 (CO2 emissions) = x 1.5 (population) x 2.5 (prosperity) x 0.5 (energy intensity) x 0.5 (carbon intensity) This Kaya Identity can be visualized as in the Figure below (the carbon intensity is represented by the size of the circles).
Evolving towards Europe or towards the US?
Energy intensity differs widely from country to country, and it is unrealistic to think that those differences can be eliminated by 2050. The US consumes more than 300 GJ per capita, about twice as much as Europe. Reducing this figure by 20%, while maintaining GDP growth, will be difficult enough. The energy consumption per capita of emerging countries like China and India is, of course, growing very rapidly, due to their fast-growing GDP. The big question is: will this growth evolve towards the energy consumption of the US, or towards that of Europe and Japan? To reach the global CO2 emissions target, the latter needs to happen, resulting in a much flatter curve of energy consumption in relation to GDP (see Figure below - left). The right part of the figure shows how various economies around the world need to reduce their carbon intensity (= size of the circles) to achieve this pathway to 2050.
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