Carbon Budget
Highlights

The annual growth rate of atmospheric CO₂ was 2.36±0.09 ppm in 2010 (ppm = parts per million), one of the largest growth rates in the past decade. The average for the decade 2000-2009 was 1.9±0.1 ppm per year, 1.5±0.1 ppm for the decade 1990-1999, and 1.6±0.1 for the decade 1980-1989. The 2010 increase brought the atmospheric CO₂ concentration to 389.6 ppm, 39% 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.

The accumulation of atmospheric CO₂ in 2010 was 5.0±0.2 Pg C, with a total cumulative of 157.5 PgC since the beginning of atmospheric high precision measurements in 1959 and 237 PgC since 1750. The rates of atmospheric CO₂ accumulation are influenced by both the anthropogenic emissions and the net uptake by natural sinks (ocean and land).

Accumulation of atmospheric CO₂ is the most accurately measured quantity in the global carbon budget with an uncertainty of about 4%. The estimated uncertainty in the global annual mean growth rate is about 0.1 ppm/yr. The data is provided by the US National Oceanic and Atmospheric Administration Earth System Research Laboratory and includes early data from the Scripps Institution of Oceanography.

CO₂ emissions from deforestation and other land use change were 0.9±0.7 PgC in 2010, leading to total emissions (including fossil fuel and land use change) of 10.0±0.9 PgC. Land use change was responsible for estimated net emissions of 1.1±0.7 PgC per year for the decade of 2000s; this is about a 25% decline from the emissions of 1.5 PgC during the 1990s, though the uncertainty is large..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.

CO₂ emissions from land use change are calculated by using a book-keeping method which used the new and revised data on land use change from the Food and agriculture Organization of the United Nationals Global Forest Resource Assessment 2010. The uncertainty on land use change emissions is the highest of any flux component of the global carbon budget.

Fossil fuel CO₂ emissions increased by 5.9% in 2010, with a total of 9.1±0.5 PgC emitted to the atmosphere (33.4 Pg of CO₂; 1 Pg = 1 billion tons or 1000 x million tons). These emissions were the highest in human history and 49% higher than in 1990 (the Kyoto reference year). Coal burning was responsible for 52% of the fossil fuel emissions growth in 2010 (gas 23% and liquid 18%).

CO₂ emissions from fossil fuel and other industrial processes are calculated by the Carbon Dioxide Information Analysis Center of the US Oak Ridge National Laboratory. For the period 1958 to 2008 the calculations were based on United Nations Energy Statistics and cement data from the US Geological Survey, and for the years 2009 and 2010 the calculations were based on BP energy data. Uncertainty of the global fossil fuel CO₂ emissions estimate is around 6-10%, and growing as the global share of emerging economies and developing countries grows. Uncertainty of emissions from individual countries can be several-fold bigger.

Contributions to global emissions growth in 2010 were largest from China (0.21 Pg above 2009 levels,10.%), USA (0.06 PgC, 4.1%), India (0.05 PgC, 9.4%), Russian Federation (0.025 PgC, 5.8%), and European Union (0.022 PgC, 2.2%), with a continuously growing global share from emerging economies. Per capita emissions of developed countries remain several times larger than those of developing countries.

The countries with highest absolute values of emissions are China (2.2 PgC), US (1.5 PgC), India (0.5 PgC), Russia (0.5 PgC), and Japan (0.3 PgC) although the emissions per capita in China (1.7 tC/person/y) and India (0.5) are still a fraction of the emissions e.g., in US (4.8), Russia (3.3) and Japan (2.5).

The abrupt decline in fossil fuel emissions by 1.3% in 2009 was indisputably the result of the global financial crisis (GFC). However, the effect was short lived as the growth rate climbed to 5.9% in 2010, the highest annual growth rate since 2003. The long-term improvement of the carbon intensity of the economy (amount of carbon emissions to produce one dollar of wealth) was -1.4% y-1 during the period 1980-2000; carbon intensity only declined by -0.9% y-1 since 2000, and increased (deterioration of carbon intensity of the economy) by +0.9% y-1 in 2010.

CO₂ emissions in developed countries decreased 1.3% in 2008 and 7.6% in 2009, but increased 3.4% in 2010. CO₂ emissions in developing countries increased 4.4% in 2008, 3.9% in 2009, and 7.6% in 2010. Based on the mean improvement in the FFCI from 2000-2010 (-0.9% y-1) and a Global Domestic Product growth rate of 4% (as estimated by the International Monetary Fund), we estimate CO₂ emissions to growth 3.1±1.5% in 2011 to reach about 9.4 PgC.

Emissions associated with the consumption of goods and service (production plus imports minus exports) take into account the growing issue of countries consuming goods which are manufactured outside of the country. Developed countries had a large drop in consumption-based emissions of 7.9% in 2009, and increased of 4.9% in 2010. In developing countries the reversed occurred. 2009 marked the first time that developing countries had higher consumption-based emissions than developed countries.

Emissions from the consumption of goods and services produced in emerging economies and developing countries but consumed in developed countries (as defined by Annex B from the Kyoto protocol) increased from 2.5 per cent of the share of developed countries in 1990 to 16 per cent in 2010, and continue to grow.

Natural land and ocean CO₂ sinks removed 56% of all CO₂ emitted from human activities during the 1958-2010, each sink in roughly equal proportion. During this period, the size of the natural sinks has grown almost at the same pace as the growth in emissions, although year-to-year variability is large. There is the possibility, however, that the fraction of all emissions remaining in the atmosphere has a positive trend due to changes in emissions growth rate and decline in the efficiency of natural sinks.

The trend in the ocean sink is estimated by using an ensemble of 5 ocean-process models for 1959-2008. For 2009 and 2010, the sink is estimated from anomalies calculated with a sub-set of these models. The models were normalized to the observed mean land and ocean sinks for 1990-2000, estimated from a range of oceanic and atmospheric observations. Models were forced with meteorological data from the US national Centers for Environmental Prediction and atmospheric CO₂ concentration. The land sink is calculated as the residual of the sum of all sources minus atmosphere+ocean sinks.