Letter | Published:

Climate impacts of oil extraction increase significantly with oilfield age

Nature Climate Change volume 7, pages 551556 (2017) | Download Citation


Record-breaking temperatures1 have induced governments to implement targets for reducing future greenhouse gas (GHG) emissions2,3. Use of oil products contributes 35% of global GHG emissions4, and the oil industry itself consumes 3–4% of global primary energy. Because oil resources are becoming increasingly heterogeneous, requiring different extraction and processing methods, GHG studies should evaluate oil sources using detailed project-specific data5. Unfortunately, prior oil-sector GHG analysis has largely neglected the fact that the energy intensity of producing oil can change significantly over the life of a particular oil project. Here we use decades-long time-series data from twenty-five globally significant oil fields (>1 billion barrels ultimate recovery) to model GHG emissions from oil production as a function of time. We find that volumetric oil production declines with depletion, but this depletion is accompanied by significant growth—in some cases over tenfold—in per-MJ GHG emissions. Depletion requires increased energy expenditures in drilling, oil recovery, and oil processing. Using probabilistic simulation, we derive a relationship for estimating GHG increases over time, showing an expected doubling in average emissions over 25 years. These trends have implications for long-term emissions and climate modelling, as well as for climate policy.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    NASA, NOAA analyses reveal record-shattering global warm temperatures in 2015. The National Aeronautics and Space Administration (accessed February 2017);

  2. 2.

    Paris Agreement (UNFCCC, 2015).

  3. 3.

    Green Transformation ‘Unstoppable’ as Countries Agree to Curb Powerful Greenhouse Gases. United Nations News Centre (15 October 2016); .

  4. 4.

    Key World Energy Statistics (Intl. Energy Agency, 2015).

  5. 5.

    , , & Know Your Oil: Creating a Global Oil-Cimate Index (Carnegie Endowment for International Peace, 2015);

  6. 6.

    , & CO2 emissions from Norwegian oil and gas extraction. Energy 90, 1956–1966 (2015).

  7. 7.

    National Inventory Report 1990–2015: Greenhouse Gas Sources and Sinks in Canada: Executive Summary (Environment Canada, accessed July 2017);

  8. 8.

    Pathways to an Energy and Carbon Efficient Russia (McKinsey Company, accessed February 2017);

  9. 9.

    Emissions of Greenhouse Gases (Statistics Norway, accessed February 2017);

  10. 10.

    Oil depletion and the energy efficiency of oil production: the case of California. Sustainability 3, 1833–1854 (2011).

  11. 11.

    et al. When comparing alternative fuel-vehicle systems, life cycle assessment studies should consider trends in oil production. J. Ind. Ecology 21, 244–248 (2017).

  12. 12.

    & A Low-Carbon Fuel Standard for California. Part 1: Technical Analysis (Inst. of Transportation Studies, Univ. of California, 2007).

  13. 13.

    & A Low-Carbon Fuel Standard for California. Part 2: Policy Analysis (Inst. of Transportation Studies, Univ. of California, 2007).

  14. 14.

    Directive 2009/30/EC of the European Parliament and of the Council of 23 April 2009. Official J. Eur. Union 140, 88–113 (2009).

  15. 15.

    et al. Oil Production Greenhouse Gas Emissions Estimator (OPGEE) v.2.0a: User Guide Technical Documentation (2017).

  16. 16.

    , & Uncertainty in regional-average petroleum GHG intensities: countering information gaps with targeted data gathering. Env. Sc. Tech. 49, 679–686 (2014).

  17. 17.

    Norway Passes the Climate Buck Again. NEWSinENGLISH (5 February 2015);

  18. 18.

    Oil and Gas Production Handbook. An Introduction to Oil and Gas Production, Transport, Refining and Petrochemical Industry (lulu.com, ABB Oil and Gas, 2013);

  19. 19.

    Norway and the environment. Binge and purge The Economist (22 January 2009);

  20. 20.

    Newfoundland and Labrador Offshore Area Gas Flaring Reduction Implementation Plan (The Canada-Newfoundland and Labrador Offshore Petroleum Board, accessed Februay 2017);

  21. 21.

    & Energetic productivity dynamics of global super-giant oilfields. Energy Env. Sci. 10, 1493–1504.

  22. 22.

    & Smart Tax: Pricing Oil for a Safe Climate (Carnegie Endowment Intl. Peace, 2016);

  23. 23.

    Resources to Reserves (Intl. Energy Agency, 2013).

  24. 24.

    Facts 2014 (Norwegian Petroleum Directorate and Norwegian Ministry of Petroleum and Energy, 2014);

  25. 25.

    , & Giant oil field decline rates and their influence on world oil production. Energy Policy 37, 2262–2272 (2009).

  26. 26.

    & Estimating decades-long trends in petroleum field energy return on investment (EROI) with an engineering-based model. PLoS ONE 12, e0171083 (2017).

  27. 27.

    , & Open-source LCA tool for estimating greenhouse gas emissions from crude oil production using field characteristics. Environ. Sci. Technol. 47, 5998–6006 (2013).

  28. 28.

    Embodied energy and GHG emissions from material use in conventional and unconventional oil and gas operations. Environ. Sci. Technol. 49, 13059–13066 (2015).

  29. 29.

    WebPlotDigitizer v.3.9 (October 2015, accessed February 2017);

Download references


V. Tripathi provided historic data for five oilfields. The Natural Sciences and Engineering Research Council of Canada (NSERC) and Ford Motor Company provided financial support to M.S.M.

Author information


  1. Department of Energy Resources Engineering, School of Earth, Energy and Environmental Sciences, Stanford University, California 94305, USA

    • Mohammad S. Masnadi
    •  & Adam R. Brandt


  1. Search for Mohammad S. Masnadi in:

  2. Search for Adam R. Brandt in:


Both M.S.M. and A.R.B. were involved in data gathering, processing and analysis of different fields. The final results were integrated and produced by M.S.M. He also wrote the manuscript, and all authors contributed to revising the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Mohammad S. Masnadi.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Information

Excel files

  1. 1.

    Supplementary Information

    Supplementary Information

  2. 2.

    Supplementary Information

    Supplementary Information

About this article

Publication history






Further reading