Population growth driving up global carbon emissions
by Greet Janssens-Maenhout, Frank Dentener, Jos Olivier
Even though the global energy share of solar, wind energy and biofuels quadrupled over the last two decades, it only amounted to about 2 per cent in 2011
Recent data from the European Commission and statistics on energy use, gas flaring and cement production, show that in 2011 anthropogenic global emissions of carbon dioxide reached an all-time high of nearly 34 billion tonnes. The top emitters in 2011 were China at 29 per cent, the United States at 16 per cent, the European Union at 11 per cent, India at 6 per cent and the Russian Federation on 5 per cent followed by Japan on 4 per cent.
An increasing world population with increasing energy needs is one of the drivers of increasing CO2 emissions. The global average emissions per person is estimated to be 4.9 t CO2 per capita, yet the top three total emitters also had highest per capita emissions: China at 7.2 t CO2 per capita; the US at 17.3 and the EU at 7.5. By comparison, India emitted only 1.6 t CO2 per capita.
In 1992, the United Nations Framework Convention on Climate Change was established with the objective of identifying what could be done to limit climate change and cope with the unavoidable impacts. The 1997 Kyoto Protocol to the convention imposed legally binding emissions targets and annual reporting obligations on industrialised – or annexe I - countries, while the non-annexe I developing countries were under no such obligations.
Since 2000, an estimated cumulative total of 420 billion tonnes of CO2 has been emitted due to human activities - including deforestation. Some scholars argue that to achieve a 75 per cent probability of limiting the long-term average global temperature rise to 2 °C above pre-industrial levels - the target adopted by the UNFCCC in Copenhagen, in 2009 - cumulative carbon emissions in the 2000–2050 period should not exceed 1,000 to 1,500 billion tonnes. Extrapolating the current global annual emission trends, which are increasingly determined by contributions from emerging economies, the cumulative emissions will already surpass this total by 2025.
Given that about three quarters of these CO2 emissions stem from fossil fuel combustion – it is important to pursue energy saving, fuel efficiency and a shift towards established low carbon energy technologies such as nuclear energy or hydropower. And modern renewable energies like solar, wind or biofuels are still needed. However, such a shift will take time, perhaps too long to really cap emissions. Even though the global energy share of solar, wind energy and biofuels quadrupled over the last two decades - it only amounted to about 2 per cent in 2011.
Nevertheless, without these modern renewables, about an extra 0.8 billion tonnes of carbon emissions would have been emitted into the atmosphere in 2011 - if it is assumed that their energy would have been generated with the current mixture of coal, oil or gas in the power and transport sectors.
Greet Janssens-Maenhout and Frank Dentener work out of the Joint Research Centre at the European Commission while Jos Olivier represents the PBL Netherlands Environmental Assessment Agency