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Tuesday, January 14, 2014

Tallying Cumulative Greenhouse Gas Emissions by Fossil Fuel Producers

Summary.  In a recent article Richard Heede has analyzed the accumulated emissions of the greenhouse gases carbon dioxide and natural gas from the beginning of the industrial revolution to the present.  He consulted a wide array of information available to the public to provide a cumulative accounting of total emissions of these gases by the emitting entities (rather than by country or region) using records beginning about 1850.

After establishing a cut-off, 90 entities, accounting for 63% of the world’s accumulated emissions over this period, qualified for tallying.  This post provides tabulated data for the top 20 entities; of these the first five are Chevron, ExxonMobil, Saudi Aramco, BP and Gazprom.

This analysis, based on the emitting entity, represents a departure from commonly used analyses of global greenhouse gas emissions.  Importantly the analysis finds that a significant number of emitting entities are based in developing countries.  This conclusion suggests that the earlier insistence by the developing countries that they be spared from requirements to limit emissions are, at least by 2010 if not before, no longer appropriate for their economic status.  Global warming is clearly a worldwide problem, requiring global approaches to combat its effects.

Introduction. It is a daunting task to track the sources of atmospheric carbon dioxide and methane, two major greenhouse gases, globally from the early days of the industrial revolution to the present.  The additional accumulation of these gases in the atmosphere originates from mankind’s extraction and burning of fossil fuels.  Richard Heede, of the Climate Accountability Institute, has done just that in his recent article “Tracing anthropogenic carbon dioxide and methane [natural gas, CH4)] emissions to fossil fuel and cement producers, 1854–2010” (Climatic Change (2014) 122:229–241;  doi:10.1007/s10584-013-0986-y; or pdf version).  Climatic Change publishes original research papers after having been rigorously evaluated by independent, anonymous reviewers.

Heede accessed information and records that are publicly available (see Details, Methods, at the end of this post) to find the total amount of fossil fuels (oil, natural gas and coal) extracted from the earth over the period analyzed.  Using the chemistry involved in burning these fuels to carbon dioxide (CO2) he calculated the resulting emissions.  In addition, carbon dioxide arising from converting limestone to cement is included in his accounting.  Furthermore Heede evaluated the amount of “fugitive” methane, a greenhouse gas about 20-30 more potent than CO2, originating from other fossil fuel operations.

Results.  Heede has found that the annual rate of global emissions originating from fossil fuels has increased dramatically since the industrial revolution began, as of course has their accumulated totals.  Annual emission rates are shown in the graphic below

Annual rates of emission of CO2 and methane (as CO2-equivalents) worldwide, and those originating from the Carbon Majors, in millions of tonnes of CO2-equivalents (MtCO2/y).
Source: Heede, (Climatic Change (2014); ).

for all industrial sources of CO2 and for methane worldwide (black curve), and for the 90 entities he tracked in detail, called the “Carbon Majors” (red curve), for the period 1850-2010.  The worldwide annual emission rates grew dramatically, on a relative basis, between about 1860 and 1910, again from about 1945 to about 1975, and is currently undergoing the sharpest rise yet starting at about 2000.  Emission rates for the Carbon Majors mirror the trends seen for total global emissions after about 1930.

Heede cites data from the U.S. Department of Energy’s Oak Ridge National Laboratory Carbon Dioxide Information Analysis Center (CDIAC) for providing an estimate for cumulative industrial CO2 emissions since 1751 of 1,336 GtCO2 (1,336,000 MtCO2 (Gt, gigatonnes; Mt, megatonnes); Heede, Online Supplementary Material (Climatic Change (2014)).  Over much of that interval, up to 1930, the cumulative emissions total remained only 10.4% of the total to 2010.  In other words, almost 90% of total worldwide emissions to 2010 have occurred in the 80 years following 1930.

The cumulative, i.e., total historic, global emissions of CO2 and methane from the 90 Carbon Majors is 63% of the total from 1750-2010; the remainder includes emissions from other, smaller entities not tracked and entities that no longer exist (Heede, Online Supplementary Material (Climatic Change (2014)).

Data for the 20 highest-emitting entities are tabulated below in Details, Cumulative emissions of carbon dioxide and methane.  The five entities with the highest cumulative emissions, as a percent of the total accumulated since 1750 are:

Chevron (USA):                          3.52%

ExxonMobil (USA):                      3.22%

Saudi Aramco (Saudi Arabia)       3.17%

BP (United Kingdom)                  2.47%

Gazprom (Russian Federation)    2.22%

These five alone represent 14.6% of the total historic emissions.  It is noteworthy that even in this upper echelon of historical emitters, entities from four nations are represented, including two that are from the developing world rather than from among industrialized nations.


Heede has performed a valuable service in this work by assessing historical emissions of major greenhouse gases according to the emitting entity instead of by region or extent of economic development.  He points out that this finding is not consistent with the early emphasis in deliberations of the United Nations leading to the Kyoto Protocol that the developing countries of the world should be absolved from constraints on emission rates.
Climate scientists agree almost unanimously that man-made emissions of greenhouse gases have led to more, and more severe, extreme weather and climate events in recent decades.  Since CO2, an important greenhouse gas, remains indefinitely in the atmosphere and cannot be removed, the present pace of occurrence of climate extremes cannot be reversed.  As emissions continue to grow, global warming will only worsen, increasing climate extremes even more.  Projections of future warming and the harms expected as a result are given in the recent Fifth Assessment Report of the Intergovernmental Panel on Climate Change issued September 2013.  For example, projections for 2046-2065 and for 2080-2100 are tabulated below, for global average temperature and sea level rise, for four emissions scenarios of increasing severity (going from RCP 2.6 to RCP 8.5). 

Changes in global mean surface temperature in ºC (top) and global mean sea level rise in m (bottom) for the two time periods shown, referenced to the period 1986-2005.  The “likely range” gives confidence limits for a 5%-95% interval.
For temperature, corresponding values for ºF are exemplified as 1ºC =1.8ºF, 2.0ºC = 3.6ºF, and 3.7ºC = 6.7ºF.
For sea level, corresponding values for feet are exemplified as 0.24 m = 0.79 ft, 0.30 m = 1.0 ft, 0.40 m = 1.3 ft, and 0.63 m = 2.1 ft.

RCP 2.6 corresponds to a scenario in which emissions fall to zero in a few decades, while RCP 8.5 corresponds to continued expansion of the energy economy with no meaningful constraints on emissions.  Currently there is no worldwide agreement to constrain emissions.  Certain regions or jurisdictions in the world, representing a small fraction of the global emission rate, have constraining policies in place and are in the early stages of implementing them.  Considered planet-wide, therefore, the current status of the energy economy is one whose emissions are largely unconstrained.

Heede’s identification of the 90 highest-emitting entities around the globe provides useful information as we consider ways to address abatement of emissions.  His approach departs from the historical focus on nations and regional associations of nations.  Global warming is truly a global problem, requiring global approaches to mitigating emissions and developing adaptive measures to allay its effects.

Methods. Heede evaluated records from all entities presently emitting 8 million tonnes of carbon (29 million tonnes of CO2 equivalent) or more per year.  This provided a total of 90 entities, grouped into 50 investor-owned companies, 31 state-owned companies and 9 current or former national agencies.  56 of the entities produce crude oil and natural gas, 37 mine coal, and 7 produce cement (for which only data after 1990 were used).

Information was gathered from corporate annual reports, company websiotes, information filed with government agencies such as the U. S. Securities and Exchange Commission, and company histories.  Carbon content of the extracted fuels was evaluated according to equivalencies established by agencies such as the Intergovernmental Panel on Climate Change, the International Energy Agency, and the U. S. Environmental Protection Agency.  This is especially important for coal, whose carbon content can vary significantly according to its type (anthracite or bituminous) and carbon purity.  Account was made not to include non-energy uses (i.e. industrial uses other than combustion for energy).  Usable information could be obtained as far back as 1854.  This history accounts for changes in corporate identities, including mergers and divestments.  It is believed that double-counting of emissions due to overlapping record sources has been minimized.

The resulting data for all 90 entities is linked for review as “Electronic supplementary material” near the end of the online version of Heede’s article .

Cumulative emissions of carbon dioxide and methane. 

The highest twenty investor- and state-owned entities and their attributed CO2 and CH4 emissions.
Entity, nation
Cumulative emissions 1854–2010, MtCO2e
Percent of global emissions, 1751–2010
2010 emissions, MtCO2e
Chevron, USA
3.52 %
ExxonMobil, USA
3.22 %
Saudi Aramco, Saudi Arabia
3.17 %
BP, United Kingdom
2.47 %
Gazprom, Russian Federation
2.22 %
Royal Dutch/Shell, Netherlands
2.12 %
National Iranian Oil Company
2.01 %
Pemex, Mexico
1.38 %
ConocoPhil-lips, USA
1.16 %
Petroleos de Venezuela
1.11 %
Coal India
1.07 %
Peabody Energy, USA
0.86 %
Total, France
0.82 %
PetroChina, China
0.73 %
Kuwait Petroleum Corp.
0.73 %
Abu Dhabi NOC, UAE
0.67 %
Sonatrach, Algeria
0.64 %
Consol Energy, Inc., USA
0.63 %
BHP-Billiton, Australia
0.52 %
Anglo American, United Kingdom
0.50 %
Sum of Top 20 IOCs & SOEs
29.54 %
Total 90 carbon majors
63.04 %
Total global emissions
100.00 %

Please note that the data in columns 3 and 4 cover different time periods.  The fourth column compares each entity’s cumulative emissions to the Carbon Dioxide Information Analysis Center’s database of global emissions 1751–2010. This table excludes British Coal, whose production and assets have not been attributed to extant companies, and also excludes five of nine nation-states (the Former Soviet Union, China, Poland, Russian Federation, and Czechoslovakia). MtCO2e, million tonnes of CO2-equivalents emitted.
Peabody Energy is the world’s largest private-sector coal company (
Abu Dhabi NOC, Abu Dhabi National Oil Company.
IOC, investor-owned company.
SOE, state-owned entity.
Source: Heede, (Climatic Change (2014);

© 2014 Henry Auer

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