The water-land-food nexus of first-generation biofuels

Abstract

Recent energy security strategies, investment opportunities and energy policies have led to an escalation in biofuel consumption at the expenses of food crops and pastureland. To evaluate the important impacts of biofuels on food security, the food-energy nexus needs to be investigated in the context of its linkages with the overall human appropriation of land and water resources. Here we provide a global assessment of biofuel crop production, reconstruct global patterns of biofuel crop/oil trade and determine the associated displacement of water and land use. We find that bioethanol is mostly produced with domestic crops while 36% of biodiesel consumption relies on international trade, mainly from Southeast Asia. Altogether, biofuels rely on about 2-3% of the global water and land used for agriculture, which could feed about 30% of the malnourished population. We evaluate the food-energy tradeoff and the impact an increased reliance on biofuel would have on the number of people the planet can feed.

Full text

1
Scientific RepoRts | 6:22521 | DOI: 10.1038/srep22521
www.nature.com/scientificreports
The water-land-food nexus of rst-
generation biofuels
Maria Cristina Rulli1, Davide Bellomi1, Andrea Cazzoli1, Giulia De Carolis1 & Paolo D’Odorico2,3
Recent energy security strategies, investment opportunities and energy policies have led to an escalation
in biofuel consumption at the expenses of food crops and pastureland. To evaluate the important impacts
of biofuels on food security, the food-energy nexus needs to be investigated in the context of its linkages
with the overall human appropriation of land and water resources. Here we provide a global assessment
of biofuel crop production, reconstruct global patterns of biofuel crop/oil trade and determine the
associated displacement of water and land use. We nd that bioethanol is mostly produced with domestic
crops while 36% of biodiesel consumption relies on international trade, mainly from Southeast Asia.
Altogether, biofuels rely on about 2-3% of the global water and land used for agriculture, which could
feed about 30% of the malnourished population. We evaluate the food-energy tradeo and the impact an
increased reliance on biofuel would have on the number of people the planet can feed.
e synthesis of biofuels from plant biomass (mostly crops) oers the opportunity to rely on energy from geo-
logically recent carbon as an alternative to fossil fuel1. e two main types of biofuels used for transportation are
bioethanol and biodiesel. e former is made from sugar and starchy crops (Fig.1A) and can be blended with
gasoline, while the latter is produced using organic fats and vegetable oils (Fig.1B) and can be blended with petrol
diesel1.
In recent years, rising interest in biofuel production has resulted both from the increase in oil prices and new
U.S. and E.U. energy policies mandating a certain degree of reliance on renewable energy as a strategy to curb
greenhouse gas (GHG) emissions from the transport sector2–4. Biofuels may contribute to the enhancement of
energy security in countries lacking direct access to fossil fuel deposits, the reduction of greenhouse gas (GHG)
emissions, and a more protable use of crops than in the food market where the same agricultural products would
oen be less valued.
e production of biofuel crops, however, can also have negative impacts on the environment, particularly
through land use change and deforestation5–10. Moreover, biofuels require water and land resources11,12 that
could otherwise be used for the production of food13,14 and ecosystem goods and services. erefore, the com-
peting needs for land and water resources by food and biofuel production are at the forefront of the energy-food
debate15,16, which is fueled by recent food crises and associated spikes in food prices17,13,4. As a result, a number
of outstanding questions on the energy-food nexus have arisen, including the number of people who could be
fed by the crops used for biofuels; the extent to which these crops, if used for food consumption in the producing
countries, could alleviate malnutrition; and whether bioenergy production entails an important displacement of
land use18 through its reliance on the trade of feedstock or vegetable oil.
Between 2000 and 2008 the consumption of alcohol for non-food uses (“other uses”, the FAO data sets)19
(i.e., bioethanol) more than doubled in the USA and underwent a ve-fold increase in Brazil, concurrently with
the global increase in bioethanol consumption reported by OECD/FAO20. Overall, in 2013 about 86 million
tons of biofuels were consumed globally, including 65 million tons of bioethanol and 21 of biodiesel. We esti-
mate that in 2013 1.91 × 106 TJ/y of bioethanol and 0.82 × 106 TJ/y of biodiesel energy were produced world-
wide (Table1), claiming an area of about 41.3 million ha, which accounts for about 4% of the global arable area,
consistent with ndings by14. Biofuel production consumed 216 billion m3 of water, which corresponds to about
3% of the global water consumption for food production21. Our results also show that, while the water footprint
of biodiesel and bioethanol energy are overall comparable, the land footprint of biodiesel is on average more
than 100% greater than that of bioethanol (Table2). ese values, however, vary substantially, depending on
the crop and geographic location.
1Departiment of Civil and Environmental Engineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133
Milan, Italy. 2Department of Environmental Sciences, University of Virginia, 291 McCormick Rd., Charlottesville, VA
22903, USA. 3National Socio-Environmental Synthesis Center, University of Maryland, Annapolis, MD 21401, USA.
Correspondence and requests for materials should be addressed to P.D. (email: paolo@virginia.edu)
Received: 26 March 2015
Accepted: 17 February 2016
Published: 03 March 2016
OPEN

www.nature.com/scientificreports/
2
Scientific RepoRts | 6:22521 | DOI: 10.1038/srep22521
Bioethanol Our ndings show that bioethanol is produced mostly with sugarcane and maize followed by
wheat, sugarbeet and sorghum (Fig. S1A). Because of its higher ethanol yield, maize accounts for 67% of the
global bioethanol supply (Fig. S1B). However, while sugarcane is by far the highest contributor to bioethanol
production (in terms of crop biomass), it is not the greatest water consumer because bioethanol produced from
maize and wheat has a greater water footprint11,12 (Fig. S1C). us the dierent bioethanol crops used by pro-
ducing countries explain their dierent use of resources (water, land, and food equivalent) (Fig.2). e impact
of bioethanol production is also evaluated in terms of the number of people who could be fed by bioethanol
crops (Fig.2D). We nd that about 200 million people could be fed by the agricultural resources used to meet the
bioethanol demand in the countries listed in Table1.
Biodiesel Biodiesel is produced in equal proportions with rapeseed, soybean and palm oil (Fig. S2A). ese
oils have comparable biodiesel yields, but dierent extraction rate (i.e., crop oil yield) resulting in the consump-
tion of a double amount of soybean compared to rapeseed (Fig. S2B). e proportion of water consumed by each
of these vegetable oils, however, is not the same: biodiesel produced with palm oil is the most water demand-
ing11,12 (Fig.3). Most of the global consumption of biodiesel takes place in OECD + EU27 countries (listed in the
caption of Table S1).
e greatest biodiesel consumers are USA and Brazil, followed by France, Germany, and Italy (Fig.3A). ese
countries (USA, France, Germany and Italy) rely mostly on rape-mustard seed and soybean oil (and, in smaller
amounts, palm oil), as do most of the other OECD + EU27 countries. Dierent oil consumption patterns are
found in Brazil, which strongly relies on soybean oil. Countries that rely more on soybean seed oil use (either
domestically or internationally) more land per unit energy consumed (Table2; Fig.3B). Because oil palm is a very
high-yield crop, soybean oil and rape-mustard seed oil consumption are the main contributors to the land foot-
print of biodiesel energy (Table2; Fig.3B). An analysis based on per capita calorie requirements and the caloric
content of biodiesel crops shows that about 70 million people could be fed by the food calories of the vegetable
oils used for biodiesel production in the top 29 consumer countries that account for 97% of the global biodiesel
consumption (Table1; Fig.3D).
Figure 1. (A) Bioethanol is obtained from carbohydrates of sugar or starchy crops via alcoholic fermentation, a
biological process in which bacteria convert sugars such as glucose, fructose and sucrose into ethanol. (B) Biodiesel
is a vegetable oil or animal fat based fuel; it consists of long-chain alkyl (methyl, ethyl, or propyl) esters. It is typically
made by chemically reacting lipids with an alcohol, which leads to the production of fatty acid esters. is chemical
reaction is known as trans-esterication.

www.nature.com/scientificreports/
3
Scientific RepoRts | 6:22521 | DOI: 10.1038/srep22521
e amounts of feedstock determined with the approach used in this study are in agreement with those
reported by other sources. For example ANP22 reports the use of 2,041 × 103 m3 of soybean oil for biodiesel con-
sumption in Brazil, while the data sources and methods used in this paper lead to an estimate of 2,480 × 103 m3.
Biofuel
energy
consumed
(103 TJ/yr)
Wat er
consumed
for biofuel
(106 m3/yr)
Area
cultivated
for biofuel
(103 ha)
People1
106 (−)
People2
106 (−)
Bioethanol
USA 1162.4 88498.6 11245.4 143.3 147.9
Brazil 506.7 30254.6 2752.0 29.1 28.6
Canada 69.3 6853.5 1127.7 9.3 8.8
China 62.0 7744.6 1212.1 10.0 8.8
Germany 32.0 1960.8 331.5 3.4 3.7
UK 19.2 1718.1 237.9 2.1 2.1
France 16.6 694.4 122.6 1.6 1.9
India 9.0 1097.4 60.7 1.0 1.0
Colombia 8.6 505.5 160.5 0.6 0.4
Sweden 7.6 598.6 106.4 0.8 0.8
Spain 7.1 665.5 95.1 1.0 1.0
Poland 6.0 387.5 99.3 0.7 0.7
Netherlands 5.0 593.0 93.6 0.6 0.6
Italy 3.1 229.2 39.6 0.4 0.4
Tot a l 1914.7 141801.4 17684.4 203.9 206.7
Biodiesel
USA 125.9 11105.5 3990.4 9.6 11.1
Brazil 101.9 10741.1 5018.2 9.9 9.9
France 94.9 7414.3 1664.1 6.8 7.5
Germany 84.8 6956.0 2626.6 6.4 7.3
Italy 46.9 4339.1 1253.9 3.8 4.2
China 39.7 2848.4 2015.3 4.0 4.3
ailand 31.3 2679.2 297.6 4.5 4.5
Spain 31.0 3446.3 432.4 2.8 4.1
Poland 25.3 1754.3 544.2 2.1 2.1
UK 25.1 2589.5 271.2 2.0 3.2
Argentina 24.7 2542.9 1585.4 2.2 2.2
Sweden 19.2 1517.4 353.7 1.5 1.7
Austria 19.1 1665.4 355.5 1.4 1.5
Colombia 18.7 1502.1 270.0 2.3 2.6
Indonesia 18.2 1980.3 175.6 3.3 2.6
Tur k e y 14.7 1362.9 331.4 1.6 1.7
Belgium 12.5 1036.0 234.1 0.9 1.1
Portugal 11.1 1158.9 529.7 0.8 0.9
Netherlands 10.8 1024.6 174.7 0.8 1.3
Canada 10.7 1116.3 318.1 0.9 1.0
Peru 9.9 678.9 90.6 1.6 1.4
Denmark 9.6 877.2 109.3 0.7 1.0
Czech Rep. 9.2 921.0 202.2 0.8 0.8
Finland 8.9 820.7 175.5 0.6 0.8
Romania 6.2 850.1 234.8 0.5 0.6
Greece 5.8 598.0 206.0 0.5 0.6
Malaysia 4.1 396.8 38.1 0.5 0.6
Slovakia 3.4 340.5 85.7 0.3 0.3
India 1.9 198.3 40.0 0.4 0.3
Tot a l 825.4 74462.2 23624.3 73.5 81.3
Grand Total2740.1 216263.5 41308.8 277.4 288.0
Table 1. A summary of the biofuel energy consumed in each country during the year 2013, the associated
consumption of water and cultivated land area, and the number of people who could be fed by the food calories
used for biofuel production considering the diets of the consumer (1) and producer (2) countries respectively.
We concentrate on the top 14 bioethanol consumers (≈ 85% of global consumption) and top 29 biodiesel consumers
(≈ 81% of global consumption; about 98% of the global biodiesel consumption is consumed by 46 countries).

www.nature.com/scientificreports/
4
Scientific RepoRts | 6:22521 | DOI: 10.1038/srep22521
In the case of Europe, USDA-GAIN23 reports for rape-seed oil a consumption of 5,770 × 103 m3, which favorably
compares with our estimate of 6,097 × 103 m3, while for soybean oil USDA-GAIN reports 850 × 103 m3, in overall
agreement with our estimate 1060 × 103 m3. Likewise, USDA-GAIN reports a combined estimate for palm oil and
used cooking oil of 2,920 × 103 m3, while our analyses show a value of 3,425 × 103 m 3. ere is an overall agree-
ment among these sources within a 10–20% tolerance.
103 m3/TJ ha/TJ cap1/TJ c ap2/TJ
Bioethanol
USA 76 10 123 127
Brazil 60 5 57 56
Canada 99 16 134 126
China 125 20 162 142
Germany 61 10 105 116
UK 89 12 112 112
France 42 7 97 113
India 122 7 112 107
Colombia 59 19 72 49
Sweden 79 14 110 110
Spain 94 13 145 140
Poland 64 16 116 116
Netherlands 118 19 114 114
Italy 73 13 126 130
Mean 82 13 113 111
Weighted mean 74 9 106 108
Biodiesel
USA 88 32 76 88
Brazil 105 49 97 97
France 78 18 71 79
Germany 82 31 75 87
Italy 88 25 76 90
China 72 51 102 109
ailand 86 10 145 145
Spain 111 14 90 134
Poland 69 22 84 84
UK 103 11 79 128
Argentina 103 64 89 89
Sweden 79 18 80 87
Austria 87 19 71 79
Colombia 80 14 122 141
Indonesia 109 10 182 145
Tur k e y 93 23 111 116
Belgium 83 19 72 86
Portugal 105 48 75 84
Netherlands 95 16 78 117
Canada 104 30 85 98
Peru 68 9 161 145
Denmark 91 11 69 103
Czech Rep 100 22 87 87
Finland 92 20 72 87
Romania 138 38 82 92
Greece 102 35 84 101
Malaysia 98 9 120 145
Slovakia 100 25 100 102
India 104 21 189 150
Mean 91 24 95 106
Weighted mean 90 29 89 99
Table 2. Water and land needed to produce one TJ of energy used in the top consuming countries during
the year 2013, and the number of people that could be fed by the associated bioethanol crops, based on
the diets of the consumer (1) and producer (2) countries, respectively. e weighted means is calculated with
respect to the amounts of energy consumed by each country.

www.nature.com/scientificreports/
5
Scientific RepoRts | 6:22521 | DOI: 10.1038/srep22521
On average, biodiesel requires about the same amount of water resources but more land than bioethanol
(Table2). e direct impact of biodiesel on food security is similar to that of bioethanol, if evaluated in terms of
number of people who could be fed per unit of biofuel energy (Table2). However, because the global production
of biodiesel is overall smaller than that of bioethanol, the impact of bioethanol on the number of people who
could be fed is greater (Figs2D and 3D).
Dependence on international trade e natural resources used for biofuel production are partly availa-
ble domestically in the country where the biofuel is consumed and partly (virtually) imported from other coun-
tries that produce and export feedstock for bioenergy. Globally, 97% of the water footprint and 96% of the land
footprint of bioethanol production are internal. For the external portion of these footprints the associated global
patterns of trade are dominated by Japan’s imports from the U.S.A. and Australia and trade partnerships internal
to South America (Fig.4).
In the case of biodiesel we were able to trace imports only for the aggregate of OECD/EU27 countries rather
than for each country individually (see Supplementary Information). For this group of countries, 59% of the
water footprint and 80% of the land footprint of biodiesel were internal. us, while most of land used to produce
bioethanol is internal to the countries where it is consumed, in the case of biodiesel there is a stronger reliance
on trade. However, even though bioethanol imports are still just a fraction of the global production, the energy
ows associated with biodiesel trade are only about ve times those for bioethanol because of the overall greater
Figure 2. For the top 14 bioethanol consumers we show the resources used for bioethanol production (A),
including both domestic production for in country use and imports) in terms of: (B) Land; (C) Water;
(D) Food equivalent, i.e., people who could be fed with crops used for bioethanol (based on country-specic
rates of calorie consumption (Table S2)). Most of the global water consumption for bioethanol production
(> 50%) is contributed by maize in the USA and sugar cane in Brazil (C). Because of their reliance on these two
dierent feedstocks, the water and land used in Brazil are substantially lower than in the USA (Table2). e
water consumed globally for bioethanol is primarily from rainwater (or “green”) (76%), though considerable
amounts of (“grey”) water for pollutant dilution (14%) and irrigation (“blue”) water (10%) are also used (Table3).

www.nature.com/scientificreports/
6
Scientific RepoRts | 6:22521 | DOI: 10.1038/srep22521
Figure 3. Biodiesel consumption (A). Land (B) and Water (C) used for biodiesel production, and (D) Number
of People who could be fed with the crops used for biodiesel production in the top 14 biodiesel consumers in the
world (based on country-specic rates of calorie consumption (Table S2)).
Figure 4. World map of energy ows related to bioethanol and biodiesel trade. e round symbol refers to
multiple countries in the area (1PJ = 1015J; 1 Ml = 106 litres). [Figure generated with ® Microso PowerPoint.
e base map is available from OpenStreetMap (http://www.openstreetmap.org/copyright ) and is licensed
under the Attribution-Share-Alike 2.0 license. e license terms can be found on the following link: http://
creativecommons.org/licenses/by-sa/2.0/].

www.nature.com/scientificreports/
7
Scientific RepoRts | 6:22521 | DOI: 10.1038/srep22521
worldwide consumption of bioethanol (Fig.4). e major energy ows related to biodiesel are from Malaysia,
Indonesia and Papua New Guinea because of palm oil trade. ere are also other important ows from South
America (soybean and rape-mustard seed oil) and Canada, (rape-mustard seed oil) (Fig.4). e European Union
is the biggest importer (Fig.4). Most of the virtual water trade (75%) associated with the biodiesel market is
contributed by palm oil, while the virtual water trade of mustard and rapeseed oil tends to occur within the
OECD + EU27 country group and cannot be resolved by our analysis (see Supplementary Materials).
e environmental impacts of European palm oil imports from Malaysia and Indonesia (Fig.4 and S3) have
been highlighted by a number of recent studies. Such impacts include high deforestation rates and large carbon
emissions in Malaysia and Indonesia due to oil palm plantations8,5 as well as losses of habitat and threats to
Green Blue Grey To t a l
(m3/GJ) (m3/GJ) (m3/GJ) (m3/GJ)
Bioethanol
USA 52.3 6.3 17.6 76.1
Brazil 53.2 2.2 4.4 59.7
Canada 80.6 1.8 16.5 98.9
China 81.6 14.4 28.9 124.8
Germany 46.1 1.0 14.1 61.2
UK 73.7 5.4 10.2 89.3
France 35.1 2.0 4.7 41.8
India 53.2 61.4 7.4 122.0
Colombia 54.5 3.9 0.4 58.8
Sweden 66.8 2.2 10.2 79.3
Spain 54.0 26.8 13.4 94.3
Poland 49.6 0.7 13.8 64.1
Netherlands 100.6 3.8 13.7 118.1
Italy 51.1 8.5 13.8 73.5
Mean 60.9 10.0 12.1 83.0
Biodiesel
USA 83.78 0.07 4.38 88.23
Brazil 104.60 0.05 0.73 105.38
France 67.58 1.52 9.02 78.13
Germany 71.22 0.31 10.51 82.04
Italy 77.38 4.41 6.13 87.92
China 65.35 0.62 5.75 71.72
ailand 79.33 0.00 6.31 85.65
Spain 96.28 10.04 4.93 111.26
Poland 68.50 0.24 0.71 69.45
UK 97.32 0.17 5.85 103.34
Argentina 102.12 0.27 0.55 102.94
Sweden 67.94 1.73 9.28 78.95
Austria 78.35 0.47 8.17 86.99
Colombia 76.67 0.02 3.64 80.33
Indonesia 101.88 0.01 7.12 109.01
Tur k e y 85.68 0.26 7.03 92.97
Belgium 75.63 1.33 5.98 82.94
Portugal 93.65 4.63 6.46 104.74
Netherlands 88.83 0.60 5.14 94.58
Canada 96.15 0.74 7.23 104.13
Peru 61.68 0.00 6.57 68.25
Denmark 85.26 0.27 5.92 91.45
Czech Republic 71.56 1.67 26.36 99.59
Finland 83.77 0.90 7.58 92.25
Romania 132.59 0.20 5.02 137.82
Greece 95.37 2.37 4.56 102.30
Malaysia 93.69 0.00 4.09 97.78
Slovakia 85.78 0.19 14.13 100.09
India 98.27 0.49 5.71 104.48
Mean 85.7 1.2 6.7 93.6
Table 3. Green, Blue, Grey water footprint components of bioethanol and biodiesel energy in the major
consuming countries.

www.nature.com/scientificreports/
8
Scientific RepoRts | 6:22521 | DOI: 10.1038/srep22521
biodiversity24. In response, the European Union has taken some action to limit these unwanted eects on the
environment25. For instance, biofuels produced from feedstocks grown on land with “high biodiversity value”
(e.g., primary forests, peatlands, wetlands, certain woodlands and grassland) are not accepted under E.U. renew-
able energy mandates. e direct and indirect eects of biofuel production on these ecosystems, however, remain
dicult to verify26.
The Water-Food-Energy Nexus First generation bioethanol (i.e., produced from food crops) is still the
major contributor to the global biofuel supply. e production of second and third generation biofuels from cel-
lulosic plant tissues or algae is overall negligible (but is expected to be substantial in the coming 10–20 years27,28),
despite their lower water and land footprints, and their lack of competition with food production.
In addition to the environmental impacts, biofuel production has important societal implications that can be
better understood by examining the energy-food-water nexus of biofuels. Crops used to produce 1 TJ of biofuel
would be sucient to feed 110 and 90 people in the case of bioethanol and biodiesel, respectively. Interestingly,
bioethanol production uses as feedstock major staple crops (e.g., maize and wheat) that could be directly used as
food. In the case of biodiesel the competition with food is partly mitigated by the growing reliance of the biofuel
industry on recycled cooking oil (up to 88% in the case of the U.K.29). At the global scale, we nd that about 280
million people (i.e., more than one fourth of the malnourished population in the world30) could be fed with the
crop calories used for biofuels in 2013. We stress, however, that this is not the number of people that would likely
see an improvement in their access to food, should biofuel use be reduced to zero. Clearly, there are important
economic and policy drivers underlying the current trends in biofuel consumption that are not accounted for
in our 1:1 replacement of biofuel with food crops. Regardless, these numbers highlight the important contrast
between biofuel production (which provides only 4 percent of energy needed by the transport sector and 0.2%
of the global energy use in all sectors31), and food security (which could be strongly enhanced by biofuel crops).
is fact calls for revisions to current climate change mitigation policies based on biofuels, as more recently rec-
ommended by the E.U.25. On April 2015 the European Parliament approved a reform of the Renewable Energy
Directive (RED), which includes a 7 percent cap on food crop based biofuels for the transport sector.
e water-food-energy nexus of biofuel consumption can be further analyzed by evaluating the tradeo
between the maximum number of people the planet could feed, and a partial conversion of the societal metabo-
lism from fossil fuel reliance to renewable energy32–34. With the industrial revolution, human societies switched
from a metabolism based only on solar energy (i.e., photosynthesis) to an increasing reliance on fossil fuels (i.e.,
solar energy from a geological past)33. anks to this reliance on fossil resources, humans have been able to
increase the agricultural production and greatly enhance their access to energy and food35. Biofuels oer a mech-
anism through which society could reduce its reliance on fossil fuels. Our study as well as recent analyses of global
food security14,36, however, have shown that the global agricultural land could not be sucient to meet the current
human demand for food and energy. How many people can be supported by the food and bioenergy the planet
can produce?Assuming a 10% reliance on biofuels (b = 0.10) (E.U., 2009) and using the bioenergy footprint val-
ues determined by this study, we nd (see Methods) that the area A can meet the food and energy requirements
of 6.7 billion people with the current average global food and energy demand. However, patterns of economic
development show shis toward higher energy consumption rates and more calorie demanding diets (e.g., more
meat) as societies become more auent37. To evaluate the impact of these increasing trends in food and energy
demand, we recalculate the population size that could be sustained (100% food and 10% transport energy) by the
same agricultural area, A, using average consumption rates characteristic of the E.U. (see Methods); in these con-
ditions the population size would be P = 4.8 billion people, which would decrease to P = 4.4 billion people with
b = 0.20 and P = 2.5 billion people with 100% reliance on biofuels for transport energy (b = 1).
Despite their being based only on average yields and consumption rates, these calculations allow us to relate
population size to its food and energy demand, and dependency on fossil fuels. ese results highlight how the
societal reliance on fossil fuels cannot be reverted by rst generation bioethanol without undermining the food
security of human societies. It should be stressed that the competition between food and biofuels is expected to
become even more intense in the near future, with the world’s population predicted to reach 9 billion by 2050.
e potential development of second and third generation biofuels is an important step in the direction of
mitigating the food-biofuel competition through new technologies relying on agricultural waste.
Methods
We use biofuel consumption data, inferred from the FAOSTAT database38, to determine the amounts and types
of crops used for bioethanol and biodiesel production in each country or country group, while the total values
of bioethanol and biodiesel production and consumption are taken from other sources (Table S1). Because the
FAOSTAT database does not provide estimates of error or uncertainty, the degree of uncertainty around the
estimates presented in this paper remains unknown. Our study reconstructs patterns of biofuel consumption and
trade using FAO data38 and other reports (i.e. Eurostat database39, US Energy International Administration40,
USDA-Foreign agricultural service-Global Agricultural Information Network,41 Epure42, UK Department for
Tra n s p or t29, French Environment and Energy Management Agency (ADEME)43, Swedish Energy Agency44,
Italian Ministry of Economic Development45, Agência Nacional do Petróleo, Gás Natural e Biocombustíveis –
ANP46), without assuming a percentage of biofuel blending with diesel or gasoline. It accounts for the eect of
trade on the water and land footprint of biofuels and determines the internal and external portion of these foot-
prints. Finally, it evaluates the extent to which biofuels can be used to reduce our societal reliance on fossil fuels,
while maintaining levels of food production that are sucient to meet the needs of the global population. For
more details, see the Supplementary Materials.

www.nature.com/scientificreports/
9
Scientific RepoRts | 6:22521 | DOI: 10.1038/srep22521
References
1. Mosdale, D. M. In Biofuels: Biotechnology, Chemistry and Sustainable Development (ed. Mosdale, D. M.), (CC Press, Taylor and
Francis, 2008).
2. U.S.A. Congress, Energy Independence and Security Act of 2007 (EISA). Pub L No. 110–140 (2007).
3. European Union, Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 on the promotion of the use
of energy from renewable sources and amending and subsequently repealing Directives 2001/77/EC and 2003/30/EC (2009).
4. Sorda, G., Banse, M. & emfert, C., An overview of biofuel policies across the world, Energ Policy. 38, 6977–6988, doi: 10.1016/j.
enpol.2010.06.066 (2010).
5. Fargione, J., Hill, J., Tilman, D., Polasy, S. & Hawthorne, P. Land clearing and the biofuel carbon debt. Science. 319, 1235–1238, doi:
10.1126/science.1152747 (2008).
6. Fitzherbert, E. B. et al. How will oil palm expansion aect biodiversity?Trends Ecol Evol. 23, 538–545, doi: 10.1016/j.tree.2008.06.012
(2008).
7. Lima, M., Sutsch, M. & de Medeiros Costa, G. Deforestation and the social impacts of soy for biodiesel: perspectives of farmers in
the south Brazilian Amazon. Ecol Soc. 16(4): 04, doi: 10.5751/ES-04366-160404 (2011).
8. Carlson, . M. et al. Committed carbon emissions, deforestation, and community land conversion from oil palm plantation
expansion in West alimantan, Indonesia. Proc Natl Acad Sci USA 109, 7559–7564, doi: 10.1073/pnas.1200452109 (2012).
9. Achten, M. J. W. & Verchot, L. V. Implications of biodiesel-induced land-use changes for CO2emissions: case studies in tropical
America, Africa, and Southeast Asia. Ecol and Soc. 16(4): 14, doi: 10.5751/ES-04403-160414 (2011).
10. Havl, P. et al. Global land-use implications of rst and second generation biofuel targets. Energ Policy. 39, 5690–5702, doi: 10.1016/j.
enpol.2010.03.030 (2011).
11. Gerbens-Leenes, P. W., Hoestra, A. Y. & van der Meer, .H. e water footprint of bioenergy. Proc Natl Acad Sci USA 106(25),
10219–10223, doi: 10.1073/pnas.0812619106 (2009).
12. Gerbens-Leenes, P. W., van Lienden, A. ., Hoestra A. Y. & van den Meer, T. H. Biofuel scenarios in a water perspective: the global
blue and green water footprint of road transport in 2030. Global Environ Chang. 22(3), 764–775, doi: 10.1016/j.
gloenvcha.2012.04.001 (2012).
13. FAO-OECD, Food and Agriculture Organization/Organization for Economic Co-operation and Development: Price Volatility in
Food and Agricultural Marets: Policy esponses.( Food and Agriculture Organization of the United Nations, 2011).
14. Cassidy, E. S., West, P. C., Gerber, J. S. & Foley, J. A. edening agricultural yields: from tonnes to people nourished per hectare.
Environ es Lett. 8, 034015, doi: 10.1088/1748-9326/8/3/034015 (2013).
15. Smith P. et al. Competition for land. Phil Trans  Soc B: Biol Sci 365, 2941–2957, doi: 10.1098/rstb.2010.0127 (2010).
16. Lambin, E. F. & Meyfroidt, P. Global land use change, economic globalization, and the looming land scarcity. Proc. Natl Acad. Sci.
USA 108, 3465–3472, doi: 10.1073/pnas.1100480108 (2011).
17. Brown, L. . In Full Planet, Empty Plates (W.W. Norton & Company 2012).
18. Meyfroidt, P. et al. Globalization of land use: distant drivers of land change and geographic displacement of land use. Curr Opin
Environ Sustain 5, 1–7, doi: 10.1016/j.cosust.2013.04.003 (2013).
19. Food and Agriculture Organization of the United Nations (FAO) in Food Balance Sheets, A Handboo. (Food and Agriculture
Organization of the United Nations 2001).
20. OECD/ Food and Agriculture Organization of the United Nations in OECD- FAO Agricultural Outloo 2013-2022, (OECD
publishing 2013).
21. Carr, J. A., D’Odorico, P., Laio, F. & idol, L. ecent history and geography of virtual water trade, PLoS One 8, e55825, doi: 10.1371/
journal.pone.0055825 (2013).
22. Agência Nacional do Petróleo, Gás Natural e Biocombustíveis – ANP, Statistic on biofuel, Available at http://www.anp.gov.br/ (Date
of access: 10/07/2015).
23. Flach, B. et al. in Biofuels annual-UE28 2015, USDA Foreign agricultural service GAIN eport Number NL5028. Available at http://
gain.fas.usda.gov/ecent%20GAIN%20Publications/Biofuels%20Annual_e%20Hague_EU-28_7-15-2015.pdf (Date of access:
20/07/2015).
24. United Nations Environment Programme, Towards sustainable production and use of resources: Assessing Biof uels, UNEP, Division of
Technology Industry and Economics, Paris (2009).
25. European Union, Proposal for a directive of the European Parliament and of the council amending Directive 98/70/EC relating to
the quality of petrol and diesel fuels and amending Directive 2009/28/EC on the promotion of the use of energy from renewable
sources, European Commission, Bruxelles (2012).
26. Hermele, . In e Appropriation of Ecological Space. Agrofuels, unequal exchange and environmental load displacements, pp. 158,
(ed. utledge 2014).
27. OECD/ Food and Agriculture Organization of the United Nations in OECD- FAO Agricultural Outloo 2014-2023, (OECD
publishing 2014).
28. Gerbens-Leenes, P. W., Xu, L., de Vries, G. J. & Hoestra A. Y. e blue water footprint and land use of biofuels from algae, Wat er
esour es, 50, 8549–8563, doi: 10.1002/2014W015710 (2014).
29. U department for Transport, in TFO 2012–2014 year four report (ed. U: Department for Transport 2014).
30. FAO, IFAD & WFP, In e State of Food Insecurity in the World 2014. Strengthening the enabling environment for food security and
nutrition. (ed. FAO 2014).
31. International Energy Agency, IEA database, Available at http://www.iea.org/statistics/statisticssearch/ (Date of access: 03/03/2015).
32. Giampietro, M. & Mayumi, . Multiple-scale integrated assessment of societal metabolism: Introducing the approach, Popul Environ
22(2), 109–153, doi: 10.1023/A:1026691623300 (2000).
33. Scheidel, A. & Sorman, A. H. Energy transitions and the global land rush: Ultimate drivers and persistent consequences. Global
Environ Chang 22, 588–595, doi: 10.1016/j.gloenvcha.2011.12.005 (2012).
34. osegrant, M. W. & Msangi, S. Consensus and Contention in the Food-Versus-Fuel Debate. Annu ev Env esour 39, 271–294, doi:
10.1146/annurev-environ-031813-132233 (2014).
35. Erisman, J. W., Sutton, M. A., Galloway, J., limont, Z. & Winiwarter, W., How a century of ammonia synthesis changed the world,
Nat Geosci 1, 636–639, doi: 10.1038/ngeo325 (2008).
36. Davis, . F., D’Odorico, P.& ulli, M. C. Moderating diets to feed the future. Earth’s Future 2, 10, 559–565, doi: 10.1002/2014EF000254
(2014).
37. Tilman, D., Balzer, C., Hill, J. & Befort, B. L. Global food demand and the sustainable intensication of agriculture. Proc Natl Acad
Sci USA 108, 20260–20264, doi: 10.1073/pnas.1116437108 (2011).
38. Food and Agriculture Organization of the United Nations. Faostat Database (2009) Available at http://faostat3.fao.org/faostat-
gateway/go/to/download/FB/*/E (Date of Access: 22/01/2014).
39. Eurostat database, http://ec.europa.eu/eurostat/en/data/database (Date of access: 10/07/2015).
40. US Energy International Administration (EIA) database, Available at http://www.eia.gov/ (Date of access: 15/07/2015).
41. USDA-Foreign agricultural service-Global Agricultural Information Networ Available at http://gain.fas.usda.gov/Pages/Default.
aspx (Date of access: 15/07/2015).
42. EPUE statistics [Available at http://www.epure.org/resources/statistics (Date of access: 15/07/2015)].

www.nature.com/scientificreports/
10
Scientific RepoRts | 6:22521 | DOI: 10.1038/srep22521
43. Charles, C., eller, M. & Moerenhout, T. Biofuels-At what cost?A review of costs and benets of France’s biofuel policies. esearch
eport (2013) International Institute for Sustainable Development -Global Subsidies Initiative. Available at https://www.iisd.org/gsi/
sites/default/… /bf_costeectiveness_france.pdf (Date of access: 15/07/2015).
44. Swedish Energy Agency, Sustainable biofuel and bioliquids Technical eport (2013) Available at https://energimyndigheten.a-w2m.
se/FolderContents.mvc/DownloadesourceId= 3037 (Date of access: 15/07/2015).
45. Italian Ministry of Economic Development, statistics on biofuel, Available at http://www.sviluppoeconomico.gov.it/index.php/it/
(Date of access: 03/03/2015)].
46. Agência Nacional do Petróleo, Gás Natural e Biocombustíveis – ANP, Statistic on biofuel, Available at http://www.anp.gov.br/ (Date
of access: 03/03/2015).
Acknowledgements
PD was funded by the National Socio-Environmental Synthesis Center, NSF DBI-1052875.
Author Contributions
M.C.R. and P.D. wrote the main manuscript text, A.C., D.B., G.D.C. and M.C.R., made calculations and prepared
the gures. All authors reviewed the manuscript.
Additional Information
Supplementary information accompanies this paper at http://www.nature.com/srep
Competing nancial interests: e authors declare no competing nancial interests.
How to cite this article: Rulli, M. C. et al. e water-land-food nexus of rst-generation biofuels. Sci. Rep. 6,
22521; doi: 10.1038/srep22521 (2016).
is work is licensed under a Creative Commons Attribution 4.0 International License. e images
or other third party material in this article are included in the article’s Creative Commons license,
unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license,
users will need to obtain permission from the license holder to reproduce the material. To view a copy of this
license, visit http://creativecommons.org/licenses/by/4.0/