Emissions from fossil fuels and cement

Emissions from fossil fuels and cement CO₂ emissions from fossil fuels burning and cement production increased by 3% in 2011, with a total of 9.5±0.5 PgC emitted to the atmosphere (34.7 billion tonnes of CO₂). These emissions were the highest in human history and 54% higher than in 1990 (the Kyoto Protocol reference year). In 2011, coal burning was responsible for 43% of the total emissions, oil 34%, gas 18%, and cement 5%.

Regional fossil fuel emissions

The biggest contributors to global emissions in 2011 were China (2.5 PgC, 28%), the United States (1.5 PgC, 16%), the European Union (EU27; 1.0 PgC, 11%), and India (0.6 PgC, 7%). Contributions to global emissions growth in 2011 were largest from China (0.226 PgC above 2010 levels, 9.9% growth) and India (0.043 PgC, 7.5%). Emissions from USA were down by 0.028 (-1.8%) and EU27 down by 0.029 PgC (-2.8%). Developing nations accounted for 60% of all emissions in 2011. Average per capita emissions of developed countries (Annex B) were 3.0tC/person, several times larger than those of developing countries (non-Annex B) which were 0.9tC/person. China's per capita emissions were 1.8 tC/person and are now close to the average of 2.0 in the EU-27. India's per capita emissions were much below at 0.5 tC/person.

Consumption-based fossil fuel emissions

Consumption-based emissions allocate emissions to where goods and services are consumed (not where they are produced and emissions released). The net emission transfer via international trade between developing countries (non-Annex B countries) and developed countries (Annex B countries) has increased from 0.03 PgC in 1990 to 0.38 PgC in 2010, with an average annual growth rate of 10%. The increase in net emission transfers of 0.35 PgC from 1990 to 2008 compares with the emission reduction of 0.2 PgC in developed countries.

Emissions from land-use change

CO₂ emissions from deforestation and other land-use change were 0.9±0.5 PgC in 2011. For the period 2002-2011, land-use change emissions accounted for 10% of all emissions from human activity (fossil fuel, cement, land-use change). The data suggest an overall decrease trend in land-use change emissions particularly since 2000. The implementation of new land policies, higher law enforcement to stop illegal deforestation, and new afforestation and regrowth of previously deforested areas could all have contributed to this decline.

Emission pathways

Current trajectories of fossil fuel emissions are tracking some of the most carbon intensive emission scenarios used in the Intergovermental Panel of Climate Change (IPCC). The current trajectory is tracking the Representative Concentration Pathway 8.5 (of the latest family of IPCC scenarios) that takes the planet to about 4°C to 6.1°C above pre-industrial times by 2100.

CO₂ removals by natural sinks

Of the total emissions from human activities during the period 2002-2011, 46% accumulated in the atmosphere, 26% in the ocean and 28% on land. During this period, the size of the natural sinks have grown almost at the same pace as the growth in emissions, although year-to-year variability is large. Climate phenomena such as the warm Southern Oscillation-El Niño can even turn the net land sink into a net source for brief periods.

Atmospheric CO₂

The annual growth rate of atmospheric CO₂ was 1.70±0.09 ppm in 2011 (ppm = parts per million), slightly below the average growth rate of 2 ppm of the past 10 years (2002-2011). The average growth rate for the decade 1990-1999 was 1.5±0.1 ppm, and was 1.6±0.1 for the decade 1980-1989. The atmospheric CO₂ concentration was 390 ppm in 2011 on average, 40% above the concentration at the start of the Industrial Revolution (about 278 ppm in 1750). The present concentration is the highest during at least the last 800,000 years.