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Country-specific dietary shifts to mitigate climate and water crises


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Undernutrition, obesity, climate change, and freshwater depletion share food and agricultural systems as an underlying driver. Efforts to more closely align dietary patterns with sustainability and health goals could be better informed with data covering the spectrum of countries characterized by over- and undernutrition. Here, we model the greenhouse gas (GHG) and water footprints of nine increasingly plant-forward diets, aligned with criteria for a healthy diet, specific to 140 countries. Results varied widely by country due to differences in: nutritional adjustments, baseline consumption patterns from which modeled diets were derived, import patterns, and the GHG- and water-intensities of foods by country of origin. Relative to exclusively plant-based (vegan) diets, diets comprised of plant foods with modest amounts of low-food chain animals (i.e., forage fish, bivalve mollusks, insects) had comparably small GHG and water footprints. In 95 percent of countries, diets that only included animal products for one meal per day were less GHG-intensive than lacto-ovo vegetarian diets (in which terrestrial and aquatic meats were eliminated entirely) in part due to the GHG-intensity of dairy foods. The relatively optimal choices among modeled diets otherwise varied across countries, in part due to contributions from deforestation (e.g., for feed production and grazing lands) and highly freshwater-intensive forms of aquaculture. Globally, modest plant-forward shifts (e.g., to low red meat diets) were offset by modeled increases in protein and caloric intake among undernourished populations, resulting in net increases in GHG and water footprints. These and other findings highlight the importance of trade, culture, and nutrition in diet footprint analyses. The country-specific results presented here could provide nutritionally-viable pathways for high-meat consuming countries as well as transitioning countries that might otherwise adopt the Western dietary pattern.
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Global Environmental Change
journal homepage:
Country-specific dietary shifts to mitigate climate and water crises
Brent F. Kim
, Raychel E. Santo
, Allysan P. Scatterday
, Jillian P. Fry
, Colleen M. Synk
Shannon R. Cebron
, Mesfin M. Mekonnen
, Arjen Y. Hoekstra
, Saskia de Pee
Martin W. Bloem
, Roni A. Neff
, Keeve E. Nachman
Johns Hopkins Center for a Livable Future, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21202, United States
Department of Environmental Health & Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, United States
Department of Health, Behavior and Society, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, United States
Department of Health Sciences, Towson University, Towson, MD, 21252, United States
Robert B. Daugherty Water for Food Global Institute, University of Nebraska, Lincoln, NE, 68508, United States
University of Twente, 7522 NB, Enschede, Netherlands
Lee Kuan Yew School of Public Policy, National University of Singapore, Singapore, 259772, Singapore
United Nations World Food Programme, Rome, 00148, Italy
Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, United States
Risk Sciences and Public Policy Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, United States
Sustainable diet
Dietary change
Food systems
Greenhouse gas emissions
Water footprint
Undernutrition, obesity, climate change, and freshwater depletion share food and agricultural systems as an
underlying driver. Efforts to more closely align dietary patterns with sustainability and health goals could be
better informed with data covering the spectrum of countries characterized by over- and undernutrition. Here,
we model the greenhouse gas (GHG) and water footprints of nine increasingly plant-forward diets, aligned with
criteria for a healthy diet, specific to 140 countries. Results varied widely by country due to differences in:
nutritional adjustments, baseline consumption patterns from which modeled diets were derived, import patterns,
and the GHG- and water-intensities of foods by country of origin. Relative to exclusively plant-based (vegan)
diets, diets comprised of plant foods with modest amounts of low-food chain animals (i.e., forage fish, bivalve
mollusks, insects) had comparably small GHG and water footprints. In 95 percent of countries, diets that only
included animal products for one meal per day were less GHG-intensive than lacto-ovo vegetarian diets (in
which terrestrial and aquatic meats were eliminated entirely) in part due to the GHG-intensity of dairy foods.
The relatively optimal choices among modeled diets otherwise varied across countries, in part due to con-
tributions from deforestation (e.g., for feed production and grazing lands) and highly freshwater-intensive forms
of aquaculture. Globally, modest plant-forward shifts (e.g., to low red meat diets) were offset by modeled in-
creases in protein and caloric intake among undernourished populations, resulting in net increases in GHG and
water footprints. These and other findings highlight the importance of trade, culture, and nutrition in diet
footprint analyses. The country-specific results presented here could provide nutritionally-viable pathways for
high-meat consuming countries as well as transitioning countries that might otherwise adopt the Western dietary
1. Introduction
Undernutrition, obesity, and climate change have been described as
a synergy of pandemics (Swinburn et al., 2019). Together with fresh-
water depletion and other related ecological harms, these intersecting
global challenges share food and agricultural systems as an underlying
driver. Leveraging those patterns presents an opportunity to address
multiple challenges in tandem, with an eye toward avoiding the
unintended consequences of making progress in some areas at the ex-
pense of others. For many low- and middle-income countries, for ex-
ample, messaging about sustainable diets is complicated by a persistent
high prevalence of all forms of undernutrition (Development Initiatives,
2018). Accounting for these and other factors at a country-specific level
could help inform efforts among high-meat consuming countries to
better align diets with public health and ecological goals, while pro-
viding nutritionally-viable strategies for transitioning countries that
Received 13 June 2018; Received in revised form 14 May 2019; Accepted 19 May 2019
Corresponding authors at: Johns Hopkins Center for a Livable Future, 111 Market Place, Suite 840, Baltimore, MD, 21202, United States.
E-mail addresses: (R.A. Neff), (K.E. Nachman).
Global Environmental Change xxx (xxxx) xxxx
0959-3780/ © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
Please cite this article as: Brent F. Kim, et al., Global Environmental Change,
might otherwise adopt the Western dietary pattern, particularly among
their urban population.
Shifts toward plant-forward diets are essential for meeting climate
change mitigation targets (Bajzelj et al., 2014;Bryngelsson et al., 2016;
Hedenus et al., 2014) and remaining within planetary boundaries
(Willett et al., 2019). These and other concerns have fueled effort-
s—proposed and enacted—to reduce animal product consumption
through approaches including behavior change campaigns (de Boer
et al., 2014d;Morris et al., 2014), environmental impact labeling
(Leach et al., 2016), dietary recommendations (Fischer and Garnett,
2016), and taxes (Säll and Gren, 2015;Springmann et al., 2017;
Wirsenius et al., 2011). At the same time, animals raised for food can
provide a range of agro-economic benefits, including converting in-
edible crop residues and by-products into human-edible food, and uti-
lizing the share of grassland unsuitable for crop production (Mottet
et al., 2017). Furthermore, animal-source foods are a valuable source of
protein and bioavailable micronutrients, especially for young children
(de Pee and Bloem, 2009d;Semba, 2016;Swinburn et al., 2019).
Policy and behavioral interventions aimed at promoting sustainable
diets could be better informed with evidence about where they could
offer the greatest potential benefits, the nutritional status of different
populations, and the relative environmental impacts of each diet in
each country. Previous studies documenting ecological impacts of
dietary scenarios have called for greater geographic specificity
(Aleksandrowicz et al., 2016;Jones et al., 2016), as most have ex-
amined only one or a few—almost exclusively industrialized—
countries, or a regional or global aggregate (Appendix A, Table A1).
To help address these gaps, we modeled the greenhouse gas (GHG)
footprint and blue and green water footprint (WF) of baseline con-
sumption patterns and nine increasingly plant-forward diets with
varying levels of animal products for 140 individual countries and
territories (henceforth: “countries”). Diets were modeled in accordance
with health criteria, offering nutritionally-viable scenarios (to the ex-
tent possible without accounting for micronutrients) that adjust for
over- and under-consumption. We account for blue water (surface and
groundwater, e.g., for irrigation) and green water (soil moisture from
precipitation); the latter is often excluded from similar studies on the
rationale that it does not directly impact water scarcity (e.g., by de-
pleting aquifers). Green water accounting is important, however, be-
cause efficient use of green water in rainfed agriculture can lessen re-
liance on blue water elsewhere. In an internationally-traded economy,
one cannot be considered independently of the other, and both are part
of an increasingly scarce global pool (Hoekstra, 2016;Schyns et al.,
2019). We also incorporate footprints of aquatic animals, nuts, and
seeds—common protein alternatives to terrestrial animal products—-
which most prior studies excluded or only narrowly considered (Ap-
pendix A, Table A1).
By accounting for import patterns and associated differences in the
GHG and water footprints of food items based on the production
practices unique to items’ countries of origin (COO), the study model
satisfies recent appeals (Heller and Keoleian, 2015;Wellesley et al.,
2015) to incorporate trade flows when measuring the environmental
impacts associated with national consumption patterns. Moreover, in-
ternational accounting systems commonly attribute environmental
impacts associated with imported foods to producing countries rather
than the countries in which they are consumed, thereby displacing
accountability away from the populations responsible for changing
demand (Dario et al., 2014;de Ruiter et al., 2016;Peters and Hertwich,
This research identifies a range of country-specific scenarios in
which dietary patterns could better align with climate change mitiga-
tion, freshwater conservation, and nutrition guidelines.
2. Methods
We developed a model to estimate the annual per capita and whole
country GHG, blue water, and green water footprints for baseline
consumption patterns and nine increasingly plant-forward diets specific
to 140 countries. We also estimate the per-serving, per-kilocalorie, per-
gram of protein, and per-kilogram edible weight footprints of common
food groups. The model was developed in Python version 3.6. Model
input and output are available in Mendeley Data (Kim et al., 2019).
2.1. Baseline consumption patterns
To characterize baseline consumption patterns for each country, we
averaged data over the 2011–2013 Food and Agriculture Organization
of the United Nations (FAO) food balance sheets (FBS) (FAO, 2017a),
which provide estimates of per capita domestic food supplies after ac-
counting for imports, exports, losses (where data are available), animal
feed, and other non-food uses (FAO, 2001). Quantities reported in FBS
reflect food availability and thus overestimate quantities actually con-
sumed. Bovine meat supplies, for example, are reported in dressed
carcass weight, which includes bones and other parts typically con-
sidered inedible. These data are appropriate for diet footprint modeling,
however, because they reflect the amount of production involved in
feeding populations (e.g., we measure the footprint of the carcass re-
quired to produce the edible portion of beef in the diet). Food balance
sheets are also well-suited for comparing consumption patterns across
countries (Fehrenbach et al., 2016) and have precedent in the literature
for measuring diet footprints across regions (Hedenus et al., 2014;Popp
et al., 2010;Pradhan et al., 2013;Tukker et al., 2011) and globally
(Bajzelj et al., 2014;Stehfest et al., 2009;Tilman and Clark, 2014).
2.2. Food losses and waste
For some items in some countries, where sufficient data were
available, FBS subtracted supply chain losses from food supply esti-
mates. We added these quantities back in to food supplies for two
reasons: First, estimates of diet footprints should reflect the fact that
some amount of waste inevitably occurs between the producer and the
consumer, thus for footprint modeling purposes we needed the original
quantities of FBS items prior to supply chain losses. Second, in cases
where it was appropriate to subtract supply chain losses—i.e., when
dealing with amounts of calories or nutrients actually consumed
(Section 2.4)—we used a more comprehensive source for food losses
and waste (Gustavsson et al., 2011); combining this with FBS estimates
would have resulted in double-counting. Detailed methods for esti-
mating food losses and waste are provided in Appendix B.1.
2.3. Food items
Study diets were comprised of 74 items in FBS (Mendeley Data
input/item_parameters). Twenty-four additional FBS items were ex-
cluded due to the small quantities in which they are typically consumed
(e.g., spices), limited footprint data (e.g., game meats), and/or because
they are not typically considered food (e.g., alcohols, cottonseed). Most
FBS items are expressed in terms of primary equivalents, i.e., the
quantity of a raw commodity required to produce a given quantity of
processed goods. For example, wheat products (e.g., wheat flour and
bread) are quantified in terms of the unprocessed wheat required for
their production, and dairy products, except for butter and cream, are
quantified as whole milk equivalents (FAO, 2001;2017b). FBS items
range from specific (e.g., bananas) to broad (e.g., freshwater fish).
Other model inputs, including trade data and item footprints, were
expressed in terms of specific items (e.g., walnuts), so we developed
schemas to match them to the associated FBS items (e.g., nuts and
For modeling purposes, we added several custom items to represent
foods either not included in FBS (e.g., edible insects) or more specific
than those in FBS. The custom item for forage fish, for example, in-
cludes small, schooling pelagic fish such as sardines and herring that
B.F. Kim, et al. Global Environmental Change xxx (xxxx) xxxx
are prey for larger species, and unlike the FBS item “Pelagic Fish” it
does not include larger species such as tuna. In Mendeley Data, custom
items are identifiable by an FBS item code of 9000 or greater.
2.4. Modeled diets
For each of the 140 study countries, we modeled nine increasingly
plant-forward diets that adhered to parameters for a healthy diet
(summarized in Fig. 1; see also Mendeley Data input/item_parameters).
Each diet used the country’s baseline consumption pattern as the
starting point. In all steps where groups of FBS items (e.g., protein
foods) were scaled up or down, the relative proportions of items within
each group were preserved, reflecting each country’s unique dietary
pattern. For example, the residents of South Korea consume relatively
little dairy, so if they removed red meat from their diet we would not
expect milk products to be a popular protein substitute. When com-
paring FBS item quantities with nutritional criteria (e.g., the target for
caloric intake described below), we first subtracted region- and food
group-specific losses occurring during processing and packaging, dis-
tribution, and consumption (Gustavsson et al., 2011). This step ensures
that criteria are met based on quantities that are closer to amounts
actually consumed, versus quantities in the food supply.
Diets were modeled as follows. First, to adjust for over- and under-
consumption, the baseline pattern was scaled to 2300 kilocalories—the
upper bound of average per capita energy requirements calculated by
Springmann et al. (2016). We held caloric intake constant across all
modeled diets for consistency when making cross-country comparisons.
In the steps described below (e.g., removing animal foods), the caloric
content of the diet underwent further changes and subsequently had to
be adjusted back to 2300, but performing this step first kept the relative
proportions of FBS items closer to the baseline. Following the initial
adjustment for caloric intake, amounts of nuts, seeds, and oils were held
constant for all diets.
Where applicable, selected animal foods were removed (Fig. 1); e.g.,
terrestrial and aquatic meats were removed from the lacto-ovo vege-
tarian diet. Modeled diets were then adjusted to meet two health
guidelines from the World Health Organization and FAO (2003): Fruits
and vegetables (excluding starchy roots, e.g., potatoes, yams) were
scaled up to a floor of 400 g per day, or approximately five servings; and
added sugars were capped to contribute no more than 10% of total
energy intake. For diets in which meat was eliminated, the fruit and
vegetable floor was raised to six or seven servings per day (Fig. 1),
based on the rationale that healthy vegetarian and vegan dietary pat-
terns tend to include more of these items (Springmann et al., 2016).
Note that we use the term “vegan” to refer to exclusively plant-based
diets, without reference to other behaviors sometimes associated with
the term, such as avoidance of leather products.
The low red meat diet additionally included a cap on red meat (i.e.,
bovine, sheep, goat, pig) of 350 g cooked weight per week, or roughly
three servings, as per recommendations (World Cancer Research Fund
and American Institute for Cancer Research, 2018). We converted the
350 g cap from cooked to raw weight (467 g) using the same conversion
factors we used for per-serving footprints (Section 2.8, Mendeley Data
input/per_unit_serving_sizes), and from raw weight to carcass weight
(648 g) using the average of FAO extraction rates for bovine and pig
meat (FAO, 2017). Taken together with adjustments for added sugars,
fruits and vegetables, calories, and protein, this diet is intended to ap-
proximate the adoption of dietary recommendations.
For the low food chain diet, protein from insects replaced 10% of
the protein from terrestrial animal products, and protein from forage
fish and bivalve mollusks replaced 70% and 30%, respectively, of the
protein from aquatic animals. Insects are not included in FBS, so nu-
tritional content was derived from Payne et al. (2016). Forage fish and
bivalve mollusks are included in FBS but grouped with other items (e.g.,
“Molluscs, Other” includes snails), so nutrient content was derived from
the United States Department of Agriculture (USDA) food composition
database (USDA, 2017). See Mendeley Data input/nu-
trient_comp_custom_items for details.
Following these adjustments, selected energy staples, i.e., FBS items
in the grains and starchy roots groups, were scaled up or down to return
to the 2300 kilocalorie target. Selected protein groups (Fig. 1) were
then scaled up as needed to meet a protein floor of 69 g per day—12%
of total energy intake, within the recommended range of 10–15%
(World Health Organization and FAO, 2003). To hold calories constant
while scaling up protein, caloric increases from protein foods were
counter-balanced with commensurate reductions in calories from en-
ergy staples. The equation for this step is provided in Appendix B.2.
We also modeled an adjusted variant of the baseline pattern, scaled
to 2300 kcal and the protein floor (Figs. 1,5b, 6). When comparing
plant-forward modeled diets with baseline consumption patterns, the
adjusted baseline allows for isolating the effects of food substitutions
independent of adjustments for over- and under-consumption.
The meatless day and two-thirds vegan diets were modeled as
combinations of two diets. Meatless day was patterned after behavior
change campaigns promoting one day of the week without meat (e.g.,
Meatless Monday) and assumes a lacto-ovo vegetarian diet for one day
per week and the adjusted baseline for the other six days. We included
this diet because it can serve as an entry point toward more plant-for-
ward diets. Two-thirds vegan was patterned loosely after “Vegan Before
6” (Bittman, 2013) and assumes a vegan diet for two out of three meals
per day and the adjusted baseline for the third, with each meal pro-
viding equal caloric content. This approach does not account for the
possibility that people in some countries may consume more animal
products at dinner, for example, compared to breakfast and lunch.
Fig. 1. Parameters for study diets. Partial shading indicates food groups that
were included only on selected days/meals, e.g., meat was included in six of
seven days for meatless day, and in one of three meals for two-thirds vegan.
Red meat includes bovine, sheep, goat, and pig meat.
When dairy products were scaled to meet the protein floor, only the FBS item
“Milk, Excluding Butter” (which also includes some milk-derived products such
as cheese and yogurt) was scaled. The FBS items “Butter, Ghee” and “Cream”
were not scaled for protein.
The fruits and vegetables floor and added sugars cap for meatless day were
only applied for one day of the week, reflecting one day of the lacto-ovo ve-
getarian diet and six days of the adjusted baseline.
The 2/3 vegan diet reflects the vegan diet for two out of three meals per day
and the adjusted baseline for the third. The fruits and vegetables floor and
added sugars cap were only applied to the two vegan meals.
For the low-food chain diet, protein from insects replaced 10% of the protein
from terrestrial animal products, and protein from forage fish and bivalve
mollusks replaced 70% and 30%, respectively, of the protein from aquatic an-
B.F. Kim, et al. Global Environmental Change xxx (xxxx) xxxx
We also included a hypothetical scenario in which all study coun-
tries adopt the average baseline consumption pattern of high-income
OECD countries (The World Bank, 2018; Figs. 1,6and 8a–d), illus-
trating potential outcomes of the Western diet becoming more wide-
spread. Furthermore, by holding diet composition constant across
countries, this scenario isolates the effects of import patterns and COOs
on GHG and water footprints.
2.5. Countries
We ran the model for the 140 countries with sufficiently robust
trade and food supply data for inclusion in the 2011–2013 FAO detailed
trade matrices and FBS (FAO, 2017a).
2.6. Import patterns and countries of origin
An item’s footprint varies based on the conditions and practices
specific to its COOs (e.g., Figs. 3 and 4). To account for these differ-
ences, for each country and diet, we traced the supply of each FBS item
back to the countries in which it was produced. Of Japan’s pig meat
supply, for example, 48% was produced domestically over 2011–2013,
22% was imported from the United States (US), 10% from Canada, 7%
from Denmark, and so on. For total imports by importing country and
FBS item, we used trade data averaged over 2011–2013 FBS, and to
allocate the share of total imports among COOs, we used 2011–2013
FAO detailed trade matrices (FAO, 2017a). Detailed methods are pro-
vided in Appendix B.3. Note that for this study, COOs were only re-
levant in cases where sufficient country-specific item footprint data
were available.
2.7. Diet footprints
2.7.1. Overview
Contributions of FBS items to diet footprints were modeled using
two approaches. The first method used country-specific footprints, i.e.,
for the items consumed in a given country, the GHG and water foot-
prints were specific to the COOs from which each item was imported.
Since we did not have sufficient country-specific data to apply this
method in all cases, it was limited to the GHG and water footprints of
terrestrial animal products (excluding insects), WFs of plant foods, and
all land use change (LUC) CO
footprints. After adapting country-spe-
cific footprint data to FBS items, this method yielded 16 009 footprint
data points (available in Mendeley Data input/item_footprints_by_coo).
These were then multiplied by the corresponding quantities of each
item, allocated over COOs, in each country-diet combination. This
method and the associated data sources are described in Sections with technical details covered in Appendix B.4.
The second method was used in cases where we did not have suf-
ficient country-specific data to differentiate footprints by COO, i.e., for
the GHG and water footprints of aquatic animals and insects, and the
GHG footprints of plant foods. For this method we performed a litera-
ture search and adapted results from 114 peer-reviewed studies,
yielding 764 data points (available in Mendeley Data input/item_-
footprints_distributions). For these item-footprint pairs, we used a
bootstrapping approach to reflect the heterogeneity across the countries
and production systems examined in the 114 studies. The bootstrapping
approach is described in Sections, with the literature search
described in Appendix B.5.
All results reflect cradle-to-farm gate activities only, and thus do not
account for GHG and water footprints associated with processing,
transportation, retail and preparation. This limitation is discussed in
Section 3.3.
While most FBS items are expressed in terms of primary equivalents,
there were some cases where we needed to allocate shares of GHG and
water footprints among processed items originating from the same root
product, e.g., butter and cream from milk. We adapted the economic
allocation method described in Hoekstra et al. (2011). The method and
how it was applied in each case are described in Appendix B.6.
2.7.2. GHG and land-use change CO
footprints of terrestrial animal
products, by COO
For GHG footprints of terrestrial animal products (excluding in-
sects), we adapted data from FAO’s Global Livestock Environmental
Assessment Model GLEAM-i tool (FAO, 2017c). The tool applies a
consistent, transparent approach to quantifying production data and
GHG emissions associated with terrestrial animal production specific to
235 different countries, accounting for differences in feed composition,
feed conversion ratios, manure management techniques, and other
parameters associated with the various species and production systems
(e.g., grasslands cattle, feedlot cattle, broiler chickens, layer chickens)
unique to each setting. The level of granularity provided by GLEAM-i
further allowed us to report CO
emissions from deforestation-driven
LUC separately from other emissions sources. These qualities made
GLEAM-i a robust choice for differentiating GHG footprints based on
Although GLEAM-i accounts for soil carbon fluxes associated with
land use change, e.g., conversion from forest to grassland, it does not
account for the effects of livestock management practices on soil carbon
losses or sequestration—an important limitation that should be ad-
dressed in future research (see Section 3.3). Furthermore, GLEAM-i
does not allocate GHG emissions to offals and other slaughter by-
products, thus overestimating the GHG footprints of meat and under-
estimating those of offals (see Appendix B.6).
With the exception of offals, the GLEAM-i tool allocates GHG
emissions from each production system among the associated animal
products (e.g., cattle meat and milk from grassland systems in Brazil)
based on protein content. The GHG footprints of these items, as re-
ported by GLEAM-i, are specific to country, production system, and
item but are not specific to the emissions source (i.e., LUC for soy feed,
LUC for palm kernel cake feed, LUC for pasture expansion, and all other
sources of GHG emissions). One of our study aims was to highlight the
contributions of deforestation to GHG footprints. To this end, we allo-
cated the GHG footprints of items among emissions sources based on
the assumption that within a given a country and production system,
the relative shares of source-specific GHG emissions among the items
from that system is the same as the relative shares of total GHG emis-
sions among those items, which was provided by GLEAM-i. For ex-
ample, for United Kingdom (UK) layer systems, based on GLEAM-i data,
82% of the total GHG footprint was allocated to eggs and 18% was
allocated to poultry meat. Thus, we applied the same percentages to
allocate LUC CO
emissions from the use of soy feed in UK layer systems
(also reported by GLEAM-i) between eggs and meat. The equations for
this method are detailed in Appendix B.4.
Since GLEAM-i reports GHG footprints per kilogram of protein, we
converted to per-kilogram primary weight footprints (e.g., carcass
weight for meat, whole milk for dairy) as follows. For each GLEAM-i
item gproduced in country c, the primary weight GHG footprint GHG
was calculated as
c g c g
c g
c g
, ,
where GHGP is the GHG footprint per kilogram of protein, PP is the
annual production in kilograms of protein, and Pis the annual pro-
duction in kilograms primary weight.
Footprints of GLEAM-i items (e.g., buffalo meat, cattle meat) then
needed to be translated to footprints of FBS items (e.g., bovine meat).
We developed schemas matching GLEAM-i countries and items to those
used in FBS. For each FBS item fproduced in country c, we then cal-
culated the primary weight GHG footprint as the average footprint of
the associated GLEAM-i item(s) gproduced in c, weighted by the ton-
nages produced P:
B.F. Kim, et al. Global Environmental Change xxx (xxxx) xxxx
( )
c f
g c c g c g
g c c g
in , ,
in ,
If there were no GLEAM-i footprint data for an FBS item in a given
country, we used a regional average, weighted by the tonnage of the
FBS item produced in each country (FAO, 2017a), as follows:
( )
r f c r c f c f
c r c f
, ,
Finally, if there were no footprint data for fin r, a weighted global
average was used.
2.7.3. Land-use change CO
footprints of soy and palm oils intended for
human consumption, by COO
Soybeans, soybean oil, palm oil, and palm kernel oil reported in FBS
food supply data reflect uses for human consumption; GHG footprints of
soy and palm as animal feed are described in Section 2.7.2. Land-use
change CO
footprints for the former items were adapted from FAO
GLEAM documentation (FAO, 2017d), which provides per-hectare LUC
footprints associated with soy and palm production for 92 (soy)
and 14 (palm) countries. Per-hectare footprints were converted to per-
kilogram footprints using country-specific crop yields from FAOSTAT,
averaged over 2011–2013. The LUC CO
footprints of soy and palm oils
were then derived from their root products using the economic allo-
cation method described in Appendix B.6. If there were no LUC CO
footprint data associated with soy or palm production in a given
country, the LUC CO
footprint was assumed to be zero.
2.7.4. Water footprints of plant foods and terrestrial animal products, by
We adapted data from literature quantifying the blue and green WFs
of plant foods (Mekonnen and Hoekstra, 2010a) and terrestrial animal
products (Mekonnen and Hoekstra, 2010b) specific to over 200 coun-
tries. We developed schemas matching countries and items from these
datasets to their FBS counterparts. Parallel to our approach for GHG
footprints, for each FBS item fproduced in country c, we calculated the
WFs as the average footprint of the associated water dataset item(s) w
produced in c, weighted by the tonnages produced P(FAO, 2017a):
( )
c f w c c w c w
w c c w
,in , ,
in ,
If there were no country production data for an item w, an un-
weighted country average was used. If there were no WF data matching
FBS item fproduced in country c, a weighted regional or global average
footprint was used, following the method described above for GLEAM-i.
One FBS item (honey) had no associated WF data and was thus
excluded from WF calculations. Mekonnen and Hoekstra’s datasets did
not include insects, so the WF of insects was taken from Miglietta et al.
(2015) and used for insect production in all countries.
Note that this method does not account for levels of water scarcity
in countries of origin. While we acknowledge that there are differing
perspectives regarding the need for scarcity-weighted WFs, our ap-
proach is informed by Hoekstra (2016), which argues that WFs have
implications for freshwater conservation wherever withdrawal occurs.
In an internationally-traded economy, all freshwater is part of an in-
creasingly scarce global pool. Even in regions with abundant freshwater
availability, if water is used inefficiently in agriculture or aquaculture,
wasted water is water that could have otherwise been used to produce
more food—thus lessening the need for other, potentially water-scarce,
regions to produce as much.
2.7.5. Bootstrapping approach for GHG footprints of plant foods, aquatic
animals, and insects
In contrast to the datasets used for footprints by COO—which used
uniform methods across FBS items and countries—plant food, aquatic
animal, and insect GHG footprints from the literature search reflected a
diversity of studies with varied methods, and represented some coun-
tries more than others. To maximize consistency across studies and with
the country-specific data describe above, we applied strict inclusion/
exclusion criteria and standardized results to the degree possible (de-
scribed in Appendix B.5); however, the practices under study still
varied greatly, e.g., by fertilizer and pesticide application rates, use of
organic practices, irrigation method, crop rotations, use of protected
cultivation (e.g., greenhouses), fish stocking density, and fishing
method (e.g., long-lining, trawling). These may not be representative of
the prevailing practices for a given country-item combination.
To account for this heterogeneity, we create a weighted probability
distribution for each FBS item’s footprint observations. When a study
provided results for multiple scenarios involving the production of the
same item in the same country, e.g., for five GHG footprint observations
for Spanish wheat with varying levels of nitrogen fertilizer inputs, we
assigned a weight to each observation equal to the reciprocal of the
number of observations, e.g., 1/5, preventing studies with multiple
observations from being overrepresented. If there were no observations
for an FBS item, proxies were used, e.g., a distribution of all grains
footprints was used for sorghum and products, and a distribution of all
citrus fruit footprints was used for grapefruit and products. All item
footprint distributions used in the model are provided in Mendeley Data
To calculate the contributions of plant foods, aquatic animals, and
insects to the GHG footprint of a country-diet combination, we used a
bootstrapping approach designed to capture the distribution of item
footprint values from the literature. The weighted distribution of GHG
footprint values for tomatoes, for example, was skewed right; simply
using the median or average would ignore this important detail. For our
approach, we 1) selected 10 000 random samples from each FBS item
footprint distribution, e.g., 10 000 samples from 23 weighted GHG
footprint values (kg CO
e/kg) for barley; 2) multiplied each sampled
footprint value by the corresponding quantity of the FBS item in the
diet, e.g., 46 kg barley/capita/year in the Moroccan vegetarian diet;
and 3) summed the resulting values for FBS items within the same
group, e.g., resulting in a distribution of 10 000 values for the kg CO
capita/year associated with grains in the Moroccan vegetarian diet.
Summing the median value from each distribution with results by COO
(Sections yielded the total per capita footprint of a given
country diet. We also present interquartile ranges (error bars in Fig. 7,
also provided in Mendeley Data output) to convey variations across
bootstrapped outputs. Note that these ranges apply only to items for
which bootstrapping was used, as the COO-specific method does not
account for uncertainty and is deterministic, returning a single footprint
value for each permutation of inputs (e.g., FBS item, diet, country, and
2.7.6. Bootstrapping approach for water footprints of aquatic animals
Aquatic animal WFs were limited to farmed species and accounted
for blue and green WFs associated with feed production and, where
applicable, blue water used to replace evaporative losses from fresh-
water ponds and to dilute seawater in brackish production. Water
footprints of wild-caught aquatic animals were assumed to be negli-
For feed-associated WFs, we created a distribution of WF values
adapted from Pahlow et al. (2015) for each FBS item associated with
farmed species. We did not have information about the share consumed
in a given country that was farmed versus wild-caught, so we made
assumptions based on 2014 global production patterns, e.g., 79% of
harvests associated with the FBS item “Freshwater Fish” were from
aquaculture (FAO, 2017e), so when this item was included in diets, we
only applied the feed-associated WF to 79% of the amount consumed
regardless of the country.
For freshwater pond aquaculture, we created a distribution of blue
WF values for each of the FBS items “Freshwater Fish” and
B.F. Kim, et al. Global Environmental Change xxx (xxxx) xxxx
“Crustaceans” (Gephart et al., 2017;Henriksson et al., 2017;Verdegem
and Bosma, 2009). For “Crustaceans” we created an additional dis-
tribution of blue WF values for brackish water pond aquaculture
(Henriksson et al., 2017;Verdegem and Bosma, 2009). Both distribu-
tions were weighted using the method described in Section 2.7.5, ex-
cept for the 31 values for freshwater production in China from Gephart
et al. (2017), which were weighted by the percentage of Chinese
freshwater production represented by each data point. We did not have
information about the shares consumed in a given country that were
from freshwater or brackish ponds, so as per our method for feed-as-
sociated WFs, we made assumptions based on 2014 global production
patterns (FAO, 2017e; Mendeley Data input/aquaculture_-
Contributions of aquatic animals to country-diet WFs were calcu-
lated as follows, using the bootstrapping approach described in Section
2.7.5. We (1) selected 10 000 random samples from each FBS item-
footprint distribution, e.g., for “Crustaceans” we selected 10 000 sam-
ples each from the distributions for feed blue WF, feed green WF,
freshwater pond blue WF, and brackish water pond blue WF; (2) mul-
tiplied each sampled footprint value by the corresponding quantity of
the FBS item in the diet; and (3) summed the resulting values for FBS
items within the same group, i.e., “Aquatic animals,” keeping results for
each water footprint type separate.
2.8. Footprints of individual food items
In addition to calculating diet footprints, we presented per-serving,
per-kilocalorie, per-gram of protein, and per-kilogram edible weight
footprints associated with grouped FBS items (Figs. 2, S1–S3). For per-
kilogram footprints, we converted carcass weight and whole aquatic
animal footprints of terrestrial and aquatic meats to edible weight
equivalents (FAO, 1989, n.d.;Nijdam et al., 2012;Waterman, 2001).
Where nut footprints were expressed in terms of in-shell, we converted
them to shelled. Although the model handled dairy products in terms of
whole milk equivalents (except for butter and cream), for comparative
purposes we added the footprints of cheese and yogurt, derived from
milk using economic allocation (see Appendix B.6). Per-kilogram edible
weight footprints were then converted to per-serving footprints using
US standards (U.S. Food and Drug Administration, 2016). Serving sizes
and conversion factors are provided in Mendeley Data input/per_-
In addition to presenting the median and interquartile range for
each group footprint, for groups with footprints specific to COO, we
calculated global averages weighted by the mass produced in each
country. For groups with footprints from our literature search, averages
were weighted by the reciprocal of the number of observations from
each study to prevent studies with multiple observations from being
overrepresented (consistent with the weighting method described in
Section 2.7.5).
3. Results and discussion
3.1. Footprints of individual food items
Our study model incorporated 3850 GHG, 5402 blue water, and
7521 green water data points (Mendeley Data input/item_-
footprints_by_coo, input/item_footprints_distributions) reflecting
cradle-to-farm gate footprints of the individual food items comprising
diets, spanning diverse production practices and conditions unique to
COO. These are presented per serving (Fig. 2), per kilocalorie (Fig. S1),
per gram of protein (Fig. S2) and per kilogram edible weight (Fig. S3) as
global averages weighted by the tonnage produced in each country
(where sufficient country-specific data were available). These figures
show footprint values aggregated over common food groups (e.g.,
grains), whereas the study model handled items with greater specificity
(e.g., maize, millet, barley).
Whether by serving, energy content, protein, or mass, ruminant
meats (i.e., bovine, sheep, goat) were by far the most GHG-intensive
items. Per serving, bovine meat (weighted average: 6.54 kg CO
ving) was 316, 115, and 40 times more GHG-intensive than pulses, nuts
Fig. 2. Average per serving (a) GHG, (b) blue water, and (c) green water item
footprints. For items with sufficient country-specific footprint data (i.e., GHG
and water footprints of terrestrial animal products excluding insects, WFs of
plant foods, and LUC CO
footprints), footprints were averaged across countries
and weighted by the tonnage produced in each country. For all other items (i.e.,
from the literature search), see Section 2.7.5 for how averages were weighted.
Most items shown here are grouped (e.g., grains); footprints associated with
specific items used in the study model (e.g., maize, millet, barley) are provided
in Mendeley Data input. Diamonds represent medians and error bars show in-
terquartile ranges. See Mendeley Data input/per_unit_serving_sizes for primary
weight to serving size conversions.
† Forage fish GHG footprints are based on sardines and herring. Pond-raised
WFs largely reflect tilapia, carp and catfish. Blue WFs for brackish pond
aquaculture reflect freshwater used to dilute seawater. Water footprints of wild-
caught aquatic animals were assumed to be negligible.
B.F. Kim, et al. Global Environmental Change xxx (xxxx) xxxx
and seeds, and soy, respectively. Insects (e.g., mealworms, crickets) and
forage fish (e.g., sardines, herring) were among the more climate-
friendly animal products, much more so than dairy. Plant foods were
generally the least GHG-intensive overall, often by an order of magni-
tude, even after accounting for GHGs associated with deforestation for
palm oils and soy.
Blue WFs of pond-raised fish (e.g., carp, tilapia, catfish; weighted
average: 698 L/serving) and farmed crustaceans (e.g., shrimp, prawns,
crayfish; weighted average: 1184 L/serving) exceeded those of other
item groups by an order of magnitude. Our model accounted for water
used in production ponds and crop production for aquaculture feed. Re-
filling ponds to replace evaporative losses, together with freshwater
used to dilute seawater in brackish production, accounted for 94.7%
and 95.1% of the blue WFs for pond-raised fish and farmed crustaceans,
Bovine meat was the only item group for which the weighted
average blue WF was greater than the 75
percentile blue WF. This
suggests that most bovine meat production occurs in countries where
blue water use for bovine meat is particularly high.
The wide interquartile ranges of country-specific item footprints
(error bars in Figs. 2, S1–S3; see also Figs. 3 and 4) illustrate variations
in the conditions and practices unique to where items are produced.
The per-kilogram GHG footprints of bovine meat from Paraguay and
Brazil, for example, were 17 and five times higher, respectively, than
that of Danish bovine meat (Fig. 3). These differences were largely at-
tributable to deforestation for grazing lands and higher methane
emissions from ruminant eructation (belching). While there were in-
sufficient data to account for COO in all cases, we did so for most of the
items with the greatest magnitude and variance in footprints, e.g., GHG
footprints of terrestrial animal products (excluding insects).
3.2. Footprints of whole diets
We modeled scenarios illustrating the potential per capita and
whole-country footprints of nine plant-forward diets. These in part re-
flect modeling choices; they represent potential outcomes for con-
sideration and may not reflect actual consumption behaviors. Scenarios
involving country-wide shifts to a particular diet, for example, are un-
likely to occur, but can reveal opportunities where policy and beha-
vioral interventions could have the broadest effect, particularly in po-
pulous countries (Figs. 6b, 8c and d).
3.2.1. Global implications of adopting the OECD diet
In a scenario in which all 140 study countries adopted the average
consumption pattern of high-income OECD countries, per capita diet-
related GHG and consumptive (blue plus green) water footprints in-
creased by an average of 135 and 47 percent, respectively, relative to
the baseline (shown for selected countries in Figs. 6,8a–d). These
findings echo prior literature (e.g., Bajzelj et al., 2014;Willett et al.,
2019) on the climate implications of rising meat and dairy intake, and
the importance of both reducing animal-product intake in high-con-
suming countries and providing viable plant-forward strategies for
transitioning countries.
3.2.2. Global implications of adjusting for under-consumption
We modeled scenarios in which dietary patterns could better align
with ecological goals alongside nutrition guidelines—while also iden-
tifying some of the challenges in doing so. For example, baseline protein
and caloric availability were below recommended levels (Section 2.4)
in 49 and 36 percent of countries, respectively. The resulting adjust-
ments for under-consumption attenuated—and in some cases com-
pletely offset—the GHG and water footprint reductions associated with
dietary shifts. For a scenario in which all 140 study countries adopted
either the low red meat or meatless day diet, our model projected an
average net increase in diet-related GHG, blue water, and green water
footprints relative to the baseline (Fig. 5a). Populous countries char-
acterized by under-consumption were the largest contributors to this
phenomenon, namely India and to a lesser degree Pakistan and In-
donesia (Figs. 6–8); loss-adjusted baseline protein availability in these
Fig. 3. Per-kilogram GHG footprints of bovine meat, by producing country, shown for countries that produced over 100 000 metric tons in 2011–2013.
Fig. 4. Per-kilogram blue and green WFs of rice, by producing country, shown
for countries that produced over 1 000 000 metric tons (1 megaton) in
B.F. Kim, et al. Global Environmental Change xxx (xxxx) xxxx
countries was 14, 9, and 12 g below the recommended minimum of
69 g, respectively. Thus, interventions that aim to address both sus-
tainability and health goals must ensure plant-forward shifts are am-
bitious enough to offset the potential ecological burdens associated
with providing adequate nutrition.
By contrast, if we hold caloric intake constant—that is, independent
of adjustments for over- and under-consumption (i.e., relative to an
adjusted variant of the baseline pattern, scaled to 2300 kcal and the
protein floor)—shifting to the low red meat or meatless day diets re-
sulted in an average net 4% or 3% reduction in diet-related GHG
footprints, respectively (Fig. 5b). Regardless of their effectiveness in
climate change mitigation, these modest shifts may offer an accessible
starting point toward more plant-forward dietary patterns.
3.2.3. Importance of country-specific analyses, trade, and countries of
The global aggregates shown in Fig. 5 are limited insofar as they
obscure the considerable variation across countries, illustrated by the
interquartile ranges. This variation was attributable to differences in
food supply composition (e.g., the degree to which the aquatic animals
group is comprised of pond-raised species), how animal products are
replaced when shifting diets, adjustments for over- and under-con-
sumption, and import patterns and the associated production practices
(e.g., pasture-based vs. intensive; irrigated vs. rainfed) and climatic
conditions (e.g., precipitation, evapotranspiration) unique to COOs. A
country-specific analysis reveals, for example, that shifting to the
meatless day diet reduced GHG and water footprints in 47% and 57% of
study countries, respectively—with some of the greatest per capita re-
ductions in Paraguay, Israel, and Brazil—even though the average net
effect was an increase in footprints. Fig. 7 further illustrates the degree
to which the relative environmental benefits among diets varied across
countries, along with the relative contributions of different food groups.
Notably, of the 140 individual countries examined in this study, mos-
t—including those identified as having the most GHG- and water-
Fig. 5. Potential per capita changes in diet-related GHG, blue water, and green water footprints across all 140 study countries, calculated as the average Δfootprint
weighted by the population of each country. Shown for the nine modeled diets relative to (a) baseline consumption patterns and (b) an adjusted variant of each
country’s baseline, scaled to 2300 kcal with a 69g/capita/day protein floor. The adjusted baseline allows for comparisons between plant-forward diets and baseline
patterns independent of adjustments for over- and under-consumption, isolating the effects of food substitutions. Diamonds represent medians and error bars show
interquartile ranges.
Fig. 6. Greenhouse gas footprints for selected diets, by country, (a) per capita and (b) for whole country populations. Countries are sorted by baseline footprint. Due
to space constraints, of the 140 study countries, only the following are shown here: (a) the 59 countries above the 58th percentile for whole country baseline
footprint, and (b) the 11 countries above the 92nd percentile for whole country baseline footprint.
B.F. Kim, et al. Global Environmental Change xxx (xxxx) xxxx
Fig. 7. Per capita diet-related GHG footprints by country, diet, and food group. Shown for the top four countries with the largest whole-country diet-related baseline
GHG footprints: (1 st) mainland China, (2nd) India, (3rd) Brazil and (4th) the United States. Indonesia, ranked 7th for whole-country footprint, is also shown as an
example of a country with high consumption of aquatic animals. Most items shown here are broadly grouped (e.g., plant foods); diet footprints are provided with
greater specificity in Mendeley Data output. Error bars show interquartile ranges and apply only to items for which bootstrapping was used, i.e., plant foods, aquatic
animals, and insects (see Section 2.7.5).
Fig. 8. Water footprints by country (a) per capita, blue WF only; (b) per capita, combined blue plus green WFs; (c) for whole countries, blue WF only; (d) for whole
countries, combined blue plus green WFs; and (e) per capita, for baseline diets only, separated by blue and green WF. Countries are sorted by (a–d) baseline footprint
or (e) blue WF. Due to space constraints, of the 140 study countries, only the following are shown here: (a, b, e) the 35 countries above the 75th percentile for whole
country baseline footprint, and (c, d) the 14 countries above the 90th percentile for whole country baseline footprint.
B.F. Kim, et al. Global Environmental Change xxx (xxxx) xxxx
intensive diets—have been vastly underrepresented in the literature
(Appendix A, Table A1).
The scenario in which countries adopt the average baseline con-
sumption pattern of high-income OECD countries (Figs. 6,8a–d) iso-
lates the effects of import patterns and COO on GHG and water foot-
prints. Holding diet composition constant across the 140 study
countries, the GHG and consumptive (blue plus green) water footprints
associated with this scenario showed substantial variation (averaging
2.5 ± 0.9 metric tons CO
e/capita/year and 1.5 ± 0.5 megaliters/
capita/year, respectively).
A number of country governments, including Brazil (Ministry of
Health of Brazil, 2014) and more recently Canada (Health Canada,
2019), have put forth dietary guidelines emphasizing predominantly
plant-based foods. While this is a critical step toward aligning domestic
consumption patterns with public health and ecological goals, coun-
tries’ production and export patterns merit additional attention. Brazil,
for example, was the top exporter of bovine meat (based on an average
of 2011–2013 data) and was in the top quartile for GHG-intensity of
bovine meat production (Fig. 3). Together with other major GHG-in-
tensive exporters such as India and Paraguay, Brazilian bovine meat
exports contributed to the large GHG footprints of diets in importing
countries like Chile, Hong Kong, Kuwait, Venezuela, and Israel. In a
hypothetical scenario in which the share of Hong Kong’s bovine meat
imports from Brazil came from Denmark instead, Hong Kong’s per ca-
pita GHG footprint for the baseline pattern was 18% lower. While not
necessarily feasible or desirable, this scenario further illustrates the
importance of accounting for trade patterns and COO.
3.2.4. Per capita GHG footprints of whole diets
The countries with the most GHG-intensive baseline consumption
patterns (Fig. 6)—and the greatest potential GHG reductions from
shifting toward plant-forward diets—included those with the highest
per capita intake of bovine meat (Argentina, Brazil, Australia), the most
GHG-intensive bovine meat production (Paraguay, Chile; Fig. 3), and
the greatest contributions of deforestation to the GHG footprints of diets
(Paraguay, Chile, Brazil; Brazil is shown in Fig. 7). Deforestation ac-
counted for 61% of the GHG footprint for the Paraguayan baseline
consumption pattern, and over 10% of the GHG footprints for 32
countries’ baseline patterns.
Over all 140 study countries, a theoretical shift to vegan diets re-
duced per capita diet-related GHG footprints by an average of 70%,
relative to the baseline (Fig. 5a). Vegan diets had the lowest per capita
GHG footprints in 97% of study countries. Given the low per-kilocalorie
GHG footprints of most plant foods (Fig. S1), even substantial increases
in consumption had only modest effects on GHG emissions of diets. For
the US vegan diet, for example, scaling up plant foods recouped 100%
of the calories and protein from animal foods with only 16% of the GHG
emissions relative to the adjusted baseline (Fig. 7).
Relative to vegan diets, low-food chain diets (i.e., predominantly
plant-based plus forage fish, bivalve mollusks, and insects) offer greater
flexibility by allowing for modest animal product intake with compar-
able environmental benefits (Fig. 5). Low-food chain diets also met the
recommended intake of vitamin B12 for adults (2.4 μg/day; Institute of
Medicine Food and Nutrition Board, 1998) in 49% of study countries,
illustrating that there may be ways to mitigate this potential limitation
of plant-forward diets even without supplementation, at least for the
general population.
Mostly plant-based diets were generally less GHG-intensive than
lacto-ovo vegetarian diets, in part due to the relatively high GHG
footprint of dairy (and eggs, depending on the basis of comparison;
Figs. 2, S1–S3) and the reliance on dairy as one of only three food
groups in the lacto-ovo vegetarian diet used to meet the protein floor
(Fig. 1). This phenomenon was particularly notable for India (Figs. 6
and 7). In 95% of countries, two-thirds vegan diets were less GHG-in-
tensive than lacto-ovo vegetarian (e.g., Figs. 6 and 7). Countries where
this was not the case included those with some of the most GHG-
intensive baseline consumption patterns (i.e., Paraguay, Chile, Argen-
tina), largely because of the GHG-intensity of ruminant meat in those
countries. In 64% of countries, the GHG footprints of no dairy diets
were lower than those of lacto-ovo vegetarian diets (e.g., India and
Indonesia, Fig. 7; also Fig. 6). In 91% of countries, the GHG footprints
of low-food chain diets were less than half those of lacto-ovo vegetarian
diets. These findings suggest populations could do far more to reduce
their climate impact by eating mostly plants with a modest amount of
low-impact meat than by eliminating meat entirely and replacing a
large share of the meat’s protein and calories with dairy.
3.2.5. Per capita water footprints of whole diets
Per capita blue WFs of diets (Fig. 8a, e) were in many cases largest
in countries with 1) low annual precipitation, increasing reliance on
irrigation for domestic crops; and 2) climatic factors such as high
temperatures that contribute to high evapotranspiration rates, and
thereby decrease crop water productivity (i.e., crop output per unit of
water consumed). These included Iran, Egypt, and Saudi Arabia. Do-
mestically-produced rice was among the top contributors in high-blue
WF countries, four of which (Kazakhstan, Afghanistan, Pakistan, Iran)
were also among the most blue water-intensive rice-producing coun-
tries (e.g., Fig. 4; rice WFs for all countries are provided in Mendeley
Data input/item_footprints_by_coo). For blue WF reductions, the most
impactful per capita dietary shifts were in Egypt, in part due to the high
blue water intensity of Egyptian bovine meat and dairy.
For baseline consumption patterns, the consumptive (blue plus
green) WF was highest for Niger (Fig. 8b, e), 98% of which was attri-
butable to green water. Domestically-grown millet was the largest
single contributor (40%) to the consumptive WF of the baseline con-
sumption pattern. Niger had by far the highest per capita millet supply
of any country, and was the 3rd largest producer and 8
most water-
intensive millet-producing country. The low water productivity of
millet in Niger was attributable to low edible yield and high evapo-
transpiration rates. Inedible millet crop residues, however, provide fuel,
construction materials, and livestock fodder (Sadras et al., 2009), il-
lustrating how sociocultural and economic provisions of agricultural
goods must be considered alongside ecological outcomes (see Section
Potential reductions in per capita consumptive WFs from shifting to
vegan diets were largest in Bolivia, Israel, and Brazil. Bovine meat,
poultry, and dairy together accounted for over half of the consumptive
WFs of the baseline consumption patterns in each of these countries. In
Israel, for example, the per capita consumptive WFs of the low-food
chain and vegan diets were 66% and 67% lower, respectively, than that
of the baseline consumption pattern. Bolivia was the most water-in-
tensive producer of bovine meat and the second for dairy, and most of
the country’s supply of these items was produced domestically. Bolivia
also has a high prevalence of anemia (Development Initiatives, 2018),
thus efforts to mitigate high WFs through dietary interventions must
give this careful consideration.
For many countries, the blue WFs of low and no red meat, no dairy,
and pescetarian diets were higher than those of baseline consumption
patterns (Figs. 5a, 8a). These diets scaled up aquatic animals, of which
the FBS items “Freshwater Fish” and “Crustaceans” were highly blue
water-intensive when raised in ponds (Figs. 2, S1–S3). Contributions of
aquatic animals to the blue WFs of baseline, low red meat, and no red
meat diets exceeded those from terrestrial meat in 29%, 34%, and 69%
of countries, respectively. In mainland China and Indonesia, for ex-
ample, aquatic animals contributed 29% and 26%, respectively, to the
blue WFs of baseline consumption patterns. In both countries, a sub-
stantial share of domestic fish production was from aquaculture (72%
and 38%, respectively), predominantly for domestic consumption and
not export (Belton et al., 2018). Replacing water-intensive pond-raised
species with forage fish and bivalve mollusks, as in the low-food chain
diet, could reduce both water and GHG footprints (see Section 3.3 re-
garding limits to increased aquatic animal intake).
B.F. Kim, et al. Global Environmental Change xxx (xxxx) xxxx
Note that we did not have information about the shares of fresh-
water fish and crustaceans consumed in a given country that were
farmed in ponds, so we made assumptions based on global production
patterns (see Section 2.7.6). This method overestimates blue WFs of
countries that source a large share of these species from wild fisheries
or non-pond aquaculture, while underestimating blue WFs of countries
for which the converse is true.
3.2.6. Targeting dietary interventions and whole-country footprints of diets
All else being equal, optimal interventions would promote dietary
shifts in countries with large potential reductions in both per capita and
whole country GHG and water footprint (acknowledging that “optimal”
depends on a wide range of factors, including many not considered
here; see Section 3.3). Based on shifting to a two-thirds vegan diet for
purely illustrative purposes, only three countries—Brazil, the US, and
Australia—were in the highest quintile for all four of the following
criteria: greatest potential per capita and whole-country reductions in
both GHG and consumptive water footprints (Fig. S4).
3.3. Limitations and opportunities for future research
There is much variability and uncertainty in accounting for post-
farm gate activities (e.g., processing, transportation, retail) and soil
carbon fluxes, and accordingly, they are rarely included in the scope of
item footprint studies. Both were thus excluded from this study. We do
not expect the former to affect our overall conclusions, as the majority
(80–86%) of diet-related GHG emissions have been attributed to the
production stage (Vermeulen et al., 2012).
Accounting for soil carbon sequestration has been shown to lower
estimates of the GHG footprints of ruminant products, particularly
those from management-intensive grazing systems (e.g., Pelletier et al.,
2010;Tichenor et al., 2017). Further research is needed to measure the
potential for soil carbon sequestration to reduce ruminant GHG foot-
prints over a broad geographic and temporal scale, given it is time-
limited; reversible; and highly context-specific based in part on soil
composition, climate, and livestock management (Garnett et al., 2017).
Conversely, the potential for soil carbon losses (e.g., from overgrazing
or feed crop production) to increase ruminant GHG footprints should
also be considered. Regardless of the uncertain role of well-managed
grazing systems in carbon sequestration, the potential benefits for soil
health, biodiversity, animal welfare, and other dimensions independent
of climate change should also be taken into consideration. Apart from
livestock production, carbon fluxes in crop and polyculture systems
should also be further explored.
Aside from shifting consumption patterns, our study model holds
other factors constant over time, including climatic conditions, popu-
lation dynamics, food wastage, trade patterns, and the GHG- and water-
intensity of production. Over the gradual course of changing diets,
these factors will change in ways that are difficult to anticipate, e.g., as
a result of rising incomes, evolving technology, changing trade policies,
and economic feedback effects. Furthermore, we assume a proportional
relationship between shifting demand and supply-side impacts, whereas
the impact of dietary shifts on blue water conservation, for example,
may be limited without policies promoting sustainable withdrawal
rates (Weindl et al., 2017). Similarly, reducing animal product intake
cannot reverse CO
emissions from deforestation unless land is taken
out of production and reforested (Searchinger et al., 2018). Given their
uncertain potential, dietary shifts should be complemented with other
behavioral and policy interventions.
Further research is needed to examine dietary shifts in the context of
social, economic, ecological, and agronomic feasibility, particularly in
low- and middle-income countries (Kiff et al., 2016), as well as the
effects on other health, social, and ecological measures not considered
here (e.g., producers’ livelihoods, land availability, biodiversity, and
eutrophication potential). Shifts to plant-forward diets, for example,
must ensure target populations have sufficient physical and economic
access to a variety of nutrient-dense plant-based foods. Agricultural
systems would need to scale up production of fruits, vegetables, and
proteins to meet the nutritional needs of the current population (KC
et al., 2018), concurrent with a more equitable redistribution of
available food. Dietary scenarios that increase aquatic animal con-
sumption, meanwhile, raise concerns regarding depletion of wild stocks
and ecological issues associated with increasing production of certain
farmed species (Thurstan and Roberts, 2014). The feasibility of sus-
tainable diets may further depend on how well proposed eating patterns
align with historical and cultural context. Van Dooren and Aiking
(2016) demonstrate a method for balancing several of these domains by
simultaneously optimizing modeled diets for nutrition, climate change
mitigation, land use, and cultural acceptability. Our use of baseline
consumption patterns as a reference point helped to preserve countries’
eating patterns when modeling diets (Section 2.4); cultural receptivity
could be further refined, however, by using national food-based dietary
guidelines (FBDGs) to define criteria for healthy diets for individual
countries, as in Vanham et al. (2018), rather than global re-
commendations (Section 2.4). Alternatively, or in cases where countries
do not have FBDGs, this research could help define FBDGs that are
healthy, sustainable, and culturally appropriate. Country-specific ana-
lyses that account for cultural acceptability could then be placed within
the context of the planetary boundaries for food systems proposed by
the EAT-Lancet Commission (Willett et al., 2019). The need to better
characterize the impacts of, viability of, and strategies for shifting to-
ward plant-forward diets, however, must be balanced against the pre-
ponderance of evidence calling for immediate action.
4. Conclusion
We evaluated nine plant-forward diets aligned with nutrition
guidelines, specific to 140 individual countries, for their potential roles
in climate change mitigation and freshwater conservation. Accounting
for country-specific differences in over- and under-consumption, trade
and baseline consumption patterns, and the GHG- and water-intensities
of foods by COO can help tailor policy and behavioral interventions.
Using this approach, we present a range of flexible options for each
country that better align dietary patterns with public health and eco-
logical goals, including viable alternatives for low- and middle-income
countries that might otherwise adopt the consumption patterns of
OECD countries.
Declaration of Interest Statement
B.F.K and S.R.C. developed the model with guidance and con-
tributions from all co-authors; J.P.F. provided guidance and expertise
on the modeling and analysis of aquatic animal footprints; M.M.M. and
A.Y.H. provided guidance and expertise on water footprints and co-
product allocation; S.D.P. and M.W.B. provided guidance and expertise
on modelling healthy diets; A.P.S., B.F.K., R.E.S., and C.M.S. performed
the search and standardization of item footprint studies; R.E.S. per-
formed the literature review of other diet footprint studies; B.F.K. and
R.E.S. wrote the manuscript; and K.E.N. and R.A.N. provided guidance
and expertise on all facets of and supervised the project. All authors
reviewed and contributed to manuscript drafts.
We thank Danielle Edwards and Emily Hu for research assistance;
Rebecca Ramsing, Alana Ridge, and Marie Spiker for general guidance
and discussions; Tomasz Filipczuk from the Crops, Livestock & Food
Statistics Team of the FAO Statistics Division for guidance on the use
B.F. Kim, et al. Global Environmental Change xxx (xxxx) xxxx
and interpretation of FAO data; and Ruth Burrows, Bailey Evenson,
Carolyn Hricko, Shawn McKenzie, Matthew Kessler, Rebecca Ramsing,
Marie Spiker, and James Yager for comments on the manuscript. This
work was supported by the Columbus Foundation. The funders had no
role in study design; data collection, analysis, or interpretation; pre-
paration of the manuscript; or decision to publish.
Supplementary information
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The water resource situation in China is severe, and conflicts between the supply and demand of water resources are prominent. Competition for water from key sectors, such as agriculture, industry, and domestic use, is widespread. The Yellow River, as one of the longest rivers in the world, is an important economic belt and an ecological barrier in China. This study considered the nine provinces along the Yellow River as the study area and the three major water-use sectors: agriculture, industry, and domestic as the research objects. The drivers of water consumption in each sector in the nine provinces along the Yellow River were analyzed using the Logarithmic Mean Divisia Index method. Based on this, a decoupling model was used to explore the relationship between water use in each sector and the corresponding level of economic development. It was found that water use intensity and economic development level were the largest negative and positive influencing factors on water use in each sector, respectively, and the opposite effects of the two may cause the Jevons paradox in water use. The overall agricultural water-saving level in the basin is high and has a large water-saving potential. The negative driving effect of the industrial structure was more significant in provinces with higher development levels. The positive driving effect of residents' consumption levels on domestic water use in rural areas was more obvious than in urban areas. The degree of decoupling between per capita and domestic water consumption in urban areas was the worst in the decoupling of water use in the agricultural, industrial, and domestic sectors and their corresponding levels of economic development. Therefore, focusing on areas with weak agricultural water conservation, promoting industrial structure upgrading, strengthening water conservation education in rural areas, and guiding the water-saving consumption habits of residents can promote the sustainable development of water resources in the provinces along the Yellow River. The research results provide insights into water conservation management in the Yellow River Basin.
... Against this backdrop, many traditional local food systems and dietary patterns have been widely recognized for their health, environmental, cultural and socio-economic values (Kim et al., 2020;Müller et al., 2020;Fridman et al., 2021). However, only recently advancements in understanding the complexity of the planetary system have quantified the positive outcomes which might be reached adopting healthy and sustainable diets (Willett et al., 2019;IPCC et al., 2019) and by switching towards more sustainable food production systems (Willett et al., 2019;Poore and Nemecek, 2018). ...
The global food system is a major contributor to climate change with 23–42% of total greenhouse gas (GHG) emissions. Thus, the transition to sustainable food systems and dietary patterns represents a big challenge and a key solution to feed a fast-growing world population while maintaining safe planet boundaries of sustainability. Organic farming is often proposed as a sustainable option, however a debate is open on its effectiveness in reducing the impact on climate when compared to conventional agriculture. Therefore, there is a need for clear indicators of climate and environmental sustainability to duly inform the food system actors and foster an effective transition towards sustainable food production and consumption. The carbon footprint (CF) is one of the most used indicators to assess the sustainability of food as it measures the contribution to climate change in terms of GHG emissions with different metrics (e.g. GHG per unit of product or per unit of land). Through a systematic analysis of the existing peer-reviewed studies allowing an unbiased comparison of product-based vs land-based CF, this study shows that organic food has on average lower impact on climate than conventional, both when the CF is assessed per ‘land unit’ (−43% GHG emissions, average) and per ‘product unit’ (−12% GHG emissions, average). However, the two CF metrics provide diverse results, even opposite in some cases, when individual conventional vs organic food types are compared: organic food results to be more sustainable than conventional in almost all cases when the ‘land unit’ CF metric is compared; conversely, conventional food results to be less impacting than organic in the 29% of cases when the ‘product unit’ CF is considered. According to these results, although the CF per unit of product is far more used and provides useful indications on the food emissions intensity, in some cases it can bring a misleading message towards unsustainability, with the paradox of making more preferable food that apparently shows lower impact per unit of product while having higher emissions per land unit. Contrariwise, the CF per unit of land better reflects the actual agricultural contribution to climate change which is driven by the land-atmosphere GHG fluxes. According to this study's results and in view of the global climate policies' targets which foster organic food production and the transition to sustainable diets, an extensive conversion of the existing global croplands into organic lands would significantly contribute to reducing total GHG emissions from the land sector.
... Some of the food uses of the different legumes have been presented in Table 4. Per capita legume consumption has been stable over the last three decades, whereas meat consumption has increased, particularly in several LMIC (low-and middle-income countries). Plantforward diets, which involve a move away from meat and toward alternate protein sources such as legumes, are seen as a way to reduce greenhouse gas emissions, water usage, and deforestation (129,130). These legumes have a high vitamin and mineral content, particularly potassium and calcium (in the case of lupines and soybeans), magnesium, iron, and zinc, as well as vitamin B1 (thiamine) and folates. ...
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Protein is one of the most important, foremost, and versatile nutrients in food. The quantity and quality of protein are determinants of its nutritional values. Therefore, adequate consumption of high-quality protein is essential for optimal growth, development, and health of humans. Based on short-term nitrogen balance studies, the Recommended Dietary Allowance of protein for the healthy adult with minimal physical activity is 0.8 g protein/kg body weight (BW) per day. Proteins are present in good quantities in not only animals but also in plants, especially in legumes. With the growing demand for protein, interest in plant proteins is also rising due to their comparative low cost as well as the increase in consumers’ demand originating from health and environmental concerns. Legumes are nutrient-dense foods, comprising components identified as “antinutritional factors” that can reduce the bioavailability of macro and micronutrients. Other than nutritive value, the physiochemical and behavioral properties of proteins during processing plays a significant role in determining the end quality of food. The term “complete protein” refers to when all nine essential amino acids are present in the correct proportion in our bodies. To have a balanced diet, the right percentage of protein is required for our body. The consumption of these high protein-containing foods will lead to protein sustainability and eradicate malnutrition. Here, we shed light on major opportunities to strengthen the contribution of diversity in legume crops products to sustainable diets. This review will boost awareness and knowledge on underutilized proteinous foods into national nutritional security programs.
Urbanization and globalization are changing the conventional constraints of seasonality and geography on food consumption, such as that of fresh cherries. The rising demand for year-round cherry consumption in China is currently satisfied by open-field, greenhouse-produced, and imported products. This study conducted a spatial-temporal life cycle evaluation of the environmental performance of cherry consumption behaviors during different seasons of the year. Moreover, based on the definitions of global and local seasonality, the additional environmental costs of out-of-season cherry consumption were estimated. Results show that seasonality was an important factor affecting the environmental burdens of cherry consumption. Eating cherries imported from Chile by air in October resulted in the highest greenhouse gas (GHG) emissions of 6.38 kg CO2-eq/kg, while eating domestic open-field cherries during May to July (the natural harvest season) was a relatively environmentally beneficial option. The total cherry consumption in China in 2019 generated GHG emissions of 126.99 × 10⁴ t CO2-eq. Under the definitions of global and local seasonality, the out-of-season consumption led to additional environmental costs of 57.59 × 10⁴ and 85.67 × 10⁴ t CO2-eq, accounting for 45.35% and 67.46% of total emissions, respectively. Furthermore, the time-environment trade-off effect of cherry consumption illustrates the higher environmental costs are exchanged for satisfying the appetite for out-of-season fresh foods. Our findings emphasize the meaningful implications for developing a sustainable consumption pattern for all stakeholders involved in the entire food chain.
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A 5-scale label that relativizes the environmental impact of a given product referred to the impact of the European food basket is proposed. It was developed based on the Product Environmental Footprint methodology with the following stepwise approach. First, a set of normalization and weighting factors were defined to aggregate all the environmental impact categories into a single dimensionless index referred to as the European food basket, coined the European Food Environmental Footprint Single Index (EFSI). Next, the effectiveness of the EFSI index was evaluated by assessing the distribution of the EFSI results on 149 hypothetical food items and comparing it with the results obtained with EC Single Score. Finally, the thresholds to translate the EFSI index into the 5-scale Enviroscore (A, B, C, D, and E) were established and validated using the Delphi method. Results indicated that both, Enviroscore and EFSI, were able to account for impact variability between and within food products. Differences on the final score were observed due to the type of products (vegetables vs. animal products), the country of origin and the mean of transportation. Regarding country of origin, results indicated that differences in water stress impact category were better captured by the EFSI index ( r = 0.624) than by the EC Single Score ( r = 0.228). Finally, good agreement achieved with the Delphi method (weighted Kappa 0.642; p = 0.0025), ensures the acceptability of the Enviroscore. In conclusion, this study developed a method to communicate environmental impact assessment in a front-of-packaging label.
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Significance Precipitation over land partitions into runoff via surface water and groundwater (blue water) and evapotranspiration (green water). We expand the traditional debate on water scarcity, which solely focuses on blue water, by assessing green water scarcity. The current debate on water scarcity is heavily skewed, since it leaves unnoticed the bulk of water availability––which is green––and the bulk of water use––which is also green. Green water is the main source of water to produce food, feed, fiber, timber, and bioenergy. Thus, to understand how freshwater scarcity constrains the production of these vital goods, explicating and including (limits to) green water use is imperative.
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Land-use changes are critical for climate policy because native vegetation and soils store abundant carbon and their losses from agricultural expansion, together with emissions from agricultural production, contribute about 20 to 25 per cent of greenhouse gas emissions1,2. Most climate strategies require maintaining or increasing land-based carbon³ while meeting food demands, which are expected to grow by more than 50 per cent by 20501,2,4. A finite global land area implies that fulfilling these strategies requires increasing global land-use efficiency of both storing carbon and producing food. Yet measuring the efficiency of land-use changes from the perspective of greenhouse gas emissions is challenging, particularly when land outputs change, for example, from one food to another or from food to carbon storage in forests. Intuitively, if a hectare of land produces maize well and forest poorly, maize should be the more efficient use of land, and vice versa. However, quantifying this difference and the yields at which the balance changes requires a common metric that factors in different outputs, emissions from different agricultural inputs (such as fertilizer) and the different productive potentials of land due to physical factors such as rainfall or soils. Here we propose a carbon benefits index that measures how changes in the output types, output quantities and production processes of a hectare of land contribute to the global capacity to store carbon and to reduce total greenhouse gas emissions. This index does not evaluate biodiversity or other ecosystem values, which must be analysed separately. We apply the index to a range of land-use and consumption choices relevant to climate policy, such as reforesting pastures, biofuel production and diet changes. We find that these choices can have much greater implications for the climate than previously understood because standard methods for evaluating the effects of land use4–11 on greenhouse gas emissions systematically underestimate the opportunity of land to store carbon if it is not used for agriculture.
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Sustainably feeding the next generation is often described as one of the most pressing "grand challenges" facing the 21 st century. Generally, scholars propose addressing this problem by increasing agricultural production, investing in technology to boost yields, changing diets, or reducing food waste. In this paper, we explore whether global food production is nutritionally balanced by comparing the diet that nutritionists recommend versus global agricultural production statistics. Results show that the global agricultural system currently overproduces grains, fats, and sugars while production of fruits and vegetables and protein is not sufficient to meet the nutritional needs of the current population. Correcting this imbalance could reduce the amount of arable land used by agriculture by 51 million ha globally but would increase total land used for agriculture by 407 million ha and increase greenhouse gas emissions. For a growing population, our calculations suggest that the only way to eat a nutritionally balanced diet, save land and reduce greenhouse gas emissions is to consume and produce more fruits and vegetables as well as transition to diets higher in plant-based protein. Such a move will help protect habitats and help meet the Sustainable Development Goals.
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The water footprint concept has been recognized as being highly valuable for raising awareness of the large quantity of water resources required to produce the food we consume. We present, for three major European countries (the United Kingdom, France and Germany), a geographically detailed nationwide food-consumption-related water footprint, taking into account socio-economic factors of food consumption, for both existing and recommended diets (healthy diet with meat, healthy pescetarian diet and healthy vegetarian diet). Using socio-economic data, national food surveys and international food consumption and water footprint databases, we were able to refine national water footprint data to the smallest possible administrative boundaries within a country (reference period 2007–2011). We found geographical differences in water footprint values for existing diets as well as for the reduction in water footprints associated with a change to the recommended healthy diets. For all 43,786 analysed geographical entities, the water footprint decreases for a healthy diet containing meat (range 11–35%). Larger reductions are observed for the healthy pescetarian (range 33–55%) and healthy vegetarian (range 35–55%) diets. In other words, shifting to a healthy diet is not only good for human health, but also substantially reduces consumption of water resources, consistently for all geographical entities throughout the three countries. Our full results are available as a supplementary dataset. These data can be used at different governance levels in order to inform policies targeted to specific geographical entities. © 2018, The Author(s), under exclusive licence to Springer Nature Limited.
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Aquaculture’s contributions to food security in the Global South are widely misunderstood. Dominant narratives suggest that aquaculture contributes mainly to international trade benefiting richer Northern consumers, or provides for wealthy urban consumers in Southern markets. On the supply side, the literature promotes an idealized vision of ‘small-scale’, low input, semi-subsistence farming as the primary means by which aquaculture can contribute to food security, or emphasizes the role of ‘industrial’ export oriented aquaculture in undermining local food security. In fact, farmed fish is produced predominantly by a ‘missing middle’ segment of commercial and increasingly intensive farms, and overwhelmingly remains in Southern domestic markets for consumption by poor and middle income consumers in both urban and rural areas, making an important but underappreciated contribution to global food security.
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The report dissects claims made by different stakeholders in the debate about so called ‘grass-fed’ beef, the greenhouse gases the animals emit, and the possibility that, through their grazing actions, they can help remove carbon dioxide from the atmosphere. It evaluates these claims and counterclaims against the best available science, providing an authoritative and evidence-based answer to the question: Is grass-fed beef good or bad for the climate?
Executive summary Malnutrition in all its forms, including obesity, undernutrition, and other dietary risks, is the leading cause of poor health globally. In the near future, the health effects of climate change will considerably compound these health challenges. Climate change can be considered a pandemic because of its sweeping effects on the health of humans and the natural systems we depend on (ie, planetary health). These three pandemics—obesity, undernutrition, and climate change—represent The Global Syndemic that affects most people in every country and region worldwide. They constitute a syndemic, or synergy of epidemics, because they co-occur in time and place, interact with each other to produce complex sequelae, and share common underlying societal drivers. This Commission recommends comprehensive actions to address obesity within the context of The Global Syndemic, which represents the paramount health challenge for humans, the environment, and our planet in the 21st century. The Global Syndemic Although the Commission's mandate was to address obesity, a deliberative process led to reframing of the problem and expansion of the mandate to offer recommendations to collectively address the triple-burden challenges of The Global Syndemic. We reframed the problem of obesity as having four parts. First, the prevalence of obesity is increasing in every region of the world. No country has successfully reversed its epidemic because the systemic and institutional drivers of obesity remain largely unabated. Second, many evidence-based policy recommendations to halt and reverse obesity rates have been endorsed by Member States at successive World Health Assembly meetings over nearly three decades, but have not yet been translated into meaningful and measurable change. Such patchy progress is due to what the Commission calls policy inertia, a collective term for the combined effects of inadequate political leadership and governance to enact policies to respond to The Global Syndemic, strong opposition to those policies by powerful commercial interests, and a lack of demand for policy action by the public. Third, similar to the 2015 Paris Agreement on Climate Change, the enormous health and economic burdens caused by obesity are not seen as urgent enough to generate the public demand or political will to implement the recommendations of expert bodies for effective action. Finally, obesity has historically been considered in isolation from other major global challenges. Linking obesity with undernutrition and climate change into a single Global Syndemic framework focuses attention on the scale and urgency of addressing these combined challenges and emphasises the need for common solutions. Syndemic drivers The Commission applied a systems perspective to understand and address the underlying drivers of The Global Syndemic within the context of achieving the broad global outcomes of human health and wellbeing, ecological health and wellbeing, social equity, and economic prosperity. The major systems driving The Global Syndemic are food and agriculture, transportation, urban design, and land use. An analysis of the dynamics of these systems sheds light on the answers to some fundamental questions. Why do these systems operate the way they do? Why do they need to change? Why are they so hard to change? What leverage points (or levers) are required to overcome policy inertia and address The Global Syndemic? The Commission identified five sets of feedback loops as the dominant dynamics underlying the answers to these questions. They include: (1) governance feedback loops that determine how political power translates into the policies and economic incentives and disincentives for companies to operate within; (2) business feedback loops that determine the dynamics for creating profitable goods and services, including the externalities associated with damage to human health, the environment, and the planet; (3) supply and demand feedback loops showing the relationships that determine current consumption practices; (4) ecological feedback loops that show the unsustainable environmental damage that the food and transportation systems impose on natural ecosystems; and (5) human health feedback loops that show the positive and negative effects that these systems have on human health. These interactions need to be elucidated and methods for reorienting these feedback systems prioritised to mitigate The Global Syndemic. Double-duty or triple-duty actions The common drivers of obesity, undernutrition, and climate change indicate that many systems-level interventions could serve as double-duty or triple-duty actions to change the trajectory of all three pandemics simultaneously. Although these actions could produce win-win, or even win-win-win, results, they are difficult to achieve. A seemingly simple example shows how challenging these actions can be. National dietary guidelines serve as a basis for the development of food and nutrition policies and public education to reduce obesity and undernutrition and could be extended to include sustainability by moving populations towards consuming largely plant-based diets. However, many countries' efforts to include environmental sustainability principles within their dietary guidelines failed due to pressure from strong food industry lobbies, especially the beef, dairy, sugar, and ultra-processed food and beverage industry sectors. Only a few countries (ie, Sweden, Germany, Qatar, and Brazil) have developed dietary guidelines that promote environmentally sustainable diets and eating patterns that ensure food security, improve diet quality, human health and wellbeing, social equity, and respond to climate change challenges. The engagement of people, communities, and diverse groups is crucial for achieving these changes. Personal behaviours are heavily influenced by environments that are obesogenic, food insecure, and promote greenhouse-gas emissions. However, people can act as agents of change in their roles as elected officials, employers, parents, customers, and citizens and influence the societal norms and institutional policies of worksites, schools, food retailers, and communities to address The Global Syndemic. Across systems and institutions, people are decision makers who can vote for, advocate for, and communicate their preferences with other decision-makers about the policies and actions needed to address The Global Syndemic. Within the natural ecosystems, people travel, recreate, build, and work in ways that can preserve or restore the environment. Collective actions can generate the momentum for change. The Commission believes that the collective influence of individuals, civil society organisations, and the public can stimulate the reorientation of human systems to promote health, equity, economic prosperity, and sustainability. Changing trends in obesity, undernutrition, and climate change Historically, the most widespread form of malnutrition has been undernutrition, including wasting, stunting, and micronutrient deficiencies. The Global Hunger Index (1992–2017) showed substantial declines in under-5 child mortality in all regions of the world but less substantial declines in the prevalence of wasting and stunting among children. However, the rates of decline in undernutrition for children and adults are still too slow to meet the Sustainable Development Goal (SDG) targets by 2030. In the past 40 years, the obesity pandemic has shifted the patterns of malnutrition. Starting in the early 1980s, rapid increases in the prevalence of overweight and obesity began in high-income countries. In 2015, obesity was estimated to affect 2 billion people worldwide. Obesity and its determinants are risk factors for three of the four leading causes of non-communicable diseases (NCDs) worldwide, including cardiovascular diseases, type 2 diabetes, and certain cancers. Extensive research on the developmental origins of health and disease has shown that fetal and infant undernutrition are risk factors for obesity and its adverse consequences throughout the life course. Low-income and middle-income countries (LMICs) carry the greatest burdens of malnutrition. In LMICs, the prevalence of overweight in children less than 5 years of age is rising on the background of an already high prevalence of stunting (28%), wasting (8·8%), and underweight (17·4%). The prevalence of obesity among stunted children is 3% and is higher among children in middle-income countries than in lower-income countries. The work of the Intergovernmental Panel on Climate Change (IPCC), three previous Lancet Commissions related to climate change and planetary health (2009–15), and the current Lancet Countdown, which is tracking progress on health and climate change from 2017 to 2030, have provided extensive and compelling projections on the major human health effects related to climate change. Chief among them are increasing food insecurity and undernutrition among vulnerable populations in many LMICs due to crop failures, reduced food production, extreme weather events that produce droughts and flooding, increased food-borne and other infectious diseases, and civil unrest. Severe food insecurity and hunger are associated with lower obesity prevalence, but mild to moderate food insecurity is paradoxically associated with higher obesity prevalence among vulnerable populations. Wealthy countries already have higher burdens of obesity and larger carbon footprints compared with LMICs. Countries transitioning from lower to higher incomes experience rapid urbanisation and shifts towards motorised transportation with consequent lower physical activity, higher prevalence of obesity, and higher greenhouse-gas emissions. Changes in the dietary patterns of populations include increasing consumption of ultra-processed food and beverage products and beef and dairy products, whose production is associated with high greenhouse-gas emissions. Agricultural production is a leading source of greenhouse-gas emissions. The economic burden of The Global Syndemic The economic burden of The Global Syndemic is substantial and will have the greatest effect on the poorest of the 8·5 billion people who will inhabit the earth by 2030. The current costs of obesity are estimated at about $2 trillion annually from direct health-care costs and lost economic productivity. These costs represent 2·8% of the world's gross domestic product (GDP) and are roughly the equivalent of the costs of smoking or armed violence and war. Economic losses attributable to undernutrition are equivalent to 11% of the GDP in Africa and Asia, or approximately $3·5 trillion annually. The World Bank estimates that an investment of $70 billion over 10 years is needed to achieve SDG targets related to undernutrition, and that achieving them would create an estimated $850 billion in economic return. The economic effects of climate change include, among others, the costs of environmental disasters (eg, drought and wildfires), changes in habitat (eg, biosecurity and sea-level rises), health effects (eg, hunger and diarrhoeal infections), industry stress in sectors such as agriculture and fisheries, and the costs of reducing greenhouse-gas emissions. Continued inaction towards the global mitigation of climate change is predicted to cost 5–10% of global GDP, whereas just 1% of the world's GDP could arrest the increase in climate change. Actions to address The Global Syndemic Many authoritative policy documents have proposed specific, evidence-informed policies to address each of the components of The Global Syndemic. Therefore, the Commission decided to focus on the common, enabling actions that would support the implementation of these policies across The Global Syndemic. A set of principles guided the Commission's recommendations to enable the implementation of existing recommended policies: be systemic in nature, address the underlying causes of The Global Syndemic and its policy inertia, forge synergies to promote health and equity, and create benefits through double-duty or triple-duty actions. The Commission identified multiple levers to strengthen governance at the global, regional, national, and local levels. The Commission proposed the use of international human rights law and to apply the concept of a right to wellbeing, which encompasses the rights of children and the rights of all people to health, adequate food, culture, and healthy environments. Global intergovernmental organisations, such as the World Trade Organization, the World Economic Forum, the World Bank, and large philanthropic foundations and regional platforms, such as the European Union, Association of Southeastern Nations, and the Pacific Forum, should play much stronger roles to support national policies that address The Global Syndemic. Many states and municipalities are leading efforts to reduce greenhouse-gas emissions by incentivising less motorised travel and improving urban food systems. Civil society organisations can create a greater demand for national policy actions with increases in capacity and funding. Therefore, in addition to the World Bank's call for $70 billion for undernutrition and the Green Climate Fund of $100 billion for LMICs to address climate change, the Commission calls for $1 billion to support the efforts of civil society organisations to advocate for policy initiatives that mitigate The Global Syndemic. A principal source of policy inertia related to addressing obesity and climate change is the power of vested interests by commercial actors whose engagement in policy often constitutes a conflict of interest that is at odds with the public good and planetary health. Countering this power to assure unbiased decision making requires strong processes to manage conflicts of interest. On the business side, new sustainable models are needed to shift outcomes from a profit-only model to a socially and environmentally viable profit model that incorporates the health of people and the environment. The fossil fuel and food industries that are responsible for driving The Global Syndemic receive more than $5 trillion in annual subsidies from governments. The Commission recommends that governments redirect these subsidies into more sustainable energy, agricultural, and food system practices. A Framework Convention on Food Systems would provide the global legal structure and direction for countries to act on improving their food systems so that they become engines for better health, environmental sustainability, greater equity, and ongoing prosperity. Stronger accountability systems are needed to ensure that governments and private-sector actors respond adequately to The Global Syndemic. Upstream monitoring is needed to measure implementation of policies, examine the commercial, political, economic and sociocultural determinants of obesity, evaluate the impact of policies and actions, and establish mechanisms to hold governments and powerful private-sector actors to account for their actions. Similarly, platforms for stakeholders to interact and secure funding, such as that provided by the EAT Forum for global food system transformation, are needed to allow collaborations of scientists, policy makers, and practitioners to co-create policy-relevant empirical, and modelling studies of The Global Syndemic and the effects of double-duty and triple-duty actions. Bringing indigenous and traditional knowledge to this effort will also be important because this knowledge is often based on principles of environmental stewardship, collective responsibilities, and the interconnectedness of people with their environments. The challenges facing action on obesity, undernutrition, and climate change are closely aligned with each other. Bringing them together under the umbrella concept of The Global Syndemic creates the potential to strengthen the action and accountabilities for all three challenges. Our health, the health of our children and future generations, and the health of the planet will depend on the implementation of comprehensive and systems-oriented responses to The Global Syndemic.
Human activities use more than half of accessible freshwater, above all for agriculture. Most approaches for reconciling water conservation with feeding a growing population focus on the cropping sector. However, livestock production is pivotal to agricultural resource use, due to its low resource-use efficiency upstream in the food supply chain. Using a global modelling approach, we quantify the current and future contribution of livestock production, under different demand- and supply-side scenarios, to the consumption of “green” precipitation water infiltrated into the soil and “blue” freshwater withdrawn from rivers, lakes and reservoirs. Currently, cropland feed production accounts for 38% of crop water consumption and grazing involves 29% of total agricultural water consumption (9990 km3 yr−1). Our analysis shows that changes in diets and livestock productivity have substantial implications for future consumption of agricultural blue water (19–36% increase compared to current levels) and green water (26–69% increase), but they can, at best, slow down trends of rising water requirements for decades to come. However, moderate productivity reductions in highly intensive livestock systems are possible without aggravating water scarcity. Productivity gains in developing regions decrease total agricultural water consumption, but lead to expansion of irrigated agriculture, due to the shift from grassland/green water to cropland/blue water resources. While the magnitude of the livestock water footprint gives cause for concern, neither dietary choices nor changes in livestock productivity will solve the water challenge of future food supply, unless accompanied by dedicated water protection policies.
Indonesia is the world's second largest seafood producer, but capture fisheries landings have slowed down over the last decade. In response, the Indonesian government has also set ambitious targets for expanding the aquaculture sector up to 2030. The present research therefore quantifies environmental impacts using life cycle assessments (LCAs), and some socioeconomic indicators, for six alternative scenarios projecting the growth of Indonesia's aquaculture up to 2030 by Tran et al. (2017). From these results, policy implications are drawn and suggestions for improvements made for gearing the Indonesian government and seafood industry towards blue growth.