Research Article

Reducing food’s environmental impacts through producers and consumers

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Science  01 Jun 2018:
Vol. 360, Issue 6392, pp. 987-992
DOI: 10.1126/science.aaq0216
  • Fig. 1 Estimated global variation in GHG emissions, land use, terrestrial acidification, eutrophication, and scarcity-weighted freshwater withdrawals, within and between 40 major foods.

    (A) Protein-rich products. Grains are also shown here given that they contribute 41% of global protein intake, despite lower protein content. (B) Milks. (C) Starch-rich products. (D) Oils. (E) Vegetables. (F) Fruits. (G) Sugars. (H) Alcoholic beverages (1 unit = 10 ml of alcohol; ABV, alcohol by volume). (I) Stimulants. n = farm or regional inventories. Pc and pctl., percentile; scty., scarcity.

  • Fig. 2 Contributions of emission sources to total farm-stage GHG emissions.

    (A and B) Gray bars show 10th- and 90th-percentile contributions. Shaded bars represent the distribution. For example, the 90th-percentile contribution of organic fertilizer N2O to farm-stage emissions is 16%, but for most wheat producers the contribution is near 0%. Density is estimated using a Gaussian kernel with bandwidth selection performed with biased cross-validation. (C and D) Contributions of emission sources for example producers with below-median GHG emissions.

  • Fig. 3 Mean and 10th-percentile GHG emissions of protein-rich products across three major production stages.

    (A to C) Red lines represent average vegetable protein emissions, and blue lines represent 10th-percentile emissions. The gray line represents 10th-percentile emissions excluding nuts, which can temporarily sequester carbon if grown on cropland or pasture. To calculate average emissions by stage, we averaged across farms that have total emissions between the 5th and 15th percentiles, controlling for burden shifting between stages.

  • Fig. 4 Graphical representation of the mitigation framework.

Supplementary Materials

  • Reducing food's environmental impacts through producers and consumers

    J. Poore and T. Nemecek

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Supplementary Text
    • Figs. S1 to S14
    • Tables S1 to 17
    • Captions for Data S1 and S2
    • References
    Data S1
    Additional reference lists.
    This file contains references for all studies used in the meta-analysis, all studies not used with justifications based on inclusion criteria, and the list of authors who contributed additional data to this study. Detailed notes on locations of data within each published study, how study data were supplemented with data provided by authors, and details of the recalculations performed, are provided in the 'Notes' column in the original model. This model is freely available for download from the link in this study.
    Data S2
    Data in spreadsheet format.
    This file contains randomized and resampled data by product at the 5th-, 10th-, 90th-, and 95th-percentiles, mean and median; data without randomization at the minimum and maximum; and GHG emissions under IPCC AR4 and AR5 characterizations. Data are provided under different functional units: Retail Weight; Nutritional Units (table S1); and food balance sheet equivalent weights (ref. 129). Sample sizes are provided for each indicator by n = observations and n = farm/regional inventories, where one observation is a line in the database and can represent multiple similar farms. This file also includes measures of skew by product, and R2, p-values, and sample sizes from the regressions in figs. S4, and S5.
     
    Correction (21 February 2019): In table S16, we erroneously reported a published number from the IMAGE integrated assessment model (17), that the land no longer required for food production under the "no animal products" scenario could remove 30 Gt CO2-C from the atmosphere (5.5 Gt CO2 yr2 over 20 years) as it naturally succeeds to forest, shrubland, or grassland. We misunderstood that the reported number also included CH4 and N2O emissions, and we considered a time frame that was too short to reflect the carbon dynamics of revegetation. Because of the error, we did not recognize the true scale of the carbon sink and therefore only included it as a sensitivity in table S16. We have now reported the sink itself separately and have changed table S16 to report a sensitivity on the carbon sink rather than reporting the sink itself.
    The original version is accessible here.

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