Lal. Carbon Footprints 2022;1:3
DOI: 10.20517/cf.2021.05
Original Article
Carbon Footprints
Open Access
Reducing carbon footprints of agriculture and food
systems
Rattan Lal
CFAES Rattan Lal Center for Carbon Management and Sequestration, The Ohio State University, Columbus, OH 43210, USA.
Correspondence to: Rattan Lal, CFAES Rattan Lal Center for Carbon Management and Sequestration, The Ohio State University,
281 W Lane Ave, Columbus, OH 43210, USA. E-mail: lal.1@osu.edu
How to cite this article: Lal R. Reducing carbon footprints of agriculture and food systems. Carbon Footprints 2022;1:3.
https://dx.doi.org/10.20517/cf.2021.05
Received: 3 Mar 2022 First Decision: 17 Mar 2022 Revised: 22 Mar 2022 Accepted: 1 Apr 2022 Published: 15 Apr 2022
Academic Editor: B. Mohan Kumar Copy Editor: Tiantian Shi Production Editor: Tiantian Shi
Abstract
Increase in global populations of humans and domesticated livestock are impacting the resource use and have a
large ecological footprint (EFP). The ever-increasing EFP of humanity is accelerating climate change, increasing
water scarcity and contamination, aggravating soil degradation, and dwindling above and below-ground
biodiversity. Several sub-components of EFP include resource footprint (RFP) which comprises land (LFP), water
(WFP), nitrogen (NFP), biodiversity (BFP) power (PFP), carbon (CFP), etc. Agricultural practices (e.g., tillage,
fertilizer and pesticide use, farm operations such as irrigation, harvesting, baling, etc.) also cause the emission of
greenhouse gases (GHGs) such as CO2, CH4, and N2O, and these gasses equivalent in their global warming potential
(GWP). In general, CFP is reported as CO2eq by converting CH4 and N2O into CO2. The Human diet, consisting of
plant and/or animal-based products and grown diversely with or without chemicals, irrigation, and modern
innovations, has a wide range of EFP. The latter, is the widely used measure of resource consumption and
humanity’s impact on the planet. EFP encompasses the cumulative GHG emissions by an individual, community,
organization, institution, nation for a specific service or product. It can vary widely because of using different
reference systems of the studies and differences in system boundaries. Therefore, standardization of the
methodologies may require a better understanding of the various ways related CFP concepts are relevant for
decisions at individual to global levels. There is no one size that fits all. It is also widely recognized that the global
average per capita CFP of humanity, estimated at 4.47 Mg CO2eq in 2020 is not sustainable, and must be reduced
to < 2 Mg CO2eqif the global warming is to be limited to 2 0C. Therefore, understanding the magnitude of CFP of
agriculture and food systems (FSs), and factors affecting it, can lead to identification of technological options which
can enhance the use efficiency of inputs, reduce wastage, and decrease the CFP. Different FSs affect CFP through
diverse components of production and supply chains, and in the manner in which food is stored and cooked and the
© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0
International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, sharing,
adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as
long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and
indicate if changes were made.
www.oaepublish.comcf
Page 2 of 19
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
waste is disposed or recycled. There is need to adopt international standard (ISO) protocol. Therefore, this review
identifies and deliberates technological options which may be needed for reducing CFP of humanity in general but
that of agriculture and FSs in particular, while also advancing Sustainable Development Goals of the Agenda 2030
of the United Nations. CFP of diverse agro-ecosystems, land use and management systems are also discussed.
Specific examples of CFP include type of farming systems (organic vs.. conventional, dietary preferences, and food
waste). There are several options for the humanity to change lifestyle and make it more sustainable. Food waste,
about one-third of all, is an important factor impacting CFP while also accelerating global warming. The impact of
avoidable food waste on gaseous emissions, estimated at 2.0 to 3.6 Mg CO2eq per Mg of food waste on dry weight
basis, must be minimized.
Keywords: Global emissions, environmental footprint, ecological footprint, carbon footprint, global warming, soil
carbon sequestration, greenhouse gases
INTRODUCTION
Anthropogenic warming of the planet is among serious global issues of the 21st Century. The present
civilization since c 1750 is appropriately called the “Carbon Civilization“(Lal[1], 2007), because of its
dependence on fossil C as a source of energy. Since the onset of Industrial Era c 1750, total anthropogenic
emissions are estimated at ~690 Pg of carbon (C), two-third of which came from fossil fuel combustion and
one-third from land use change [Table 1]. However, ~30% of the anthropogenic emissions have been and
are absorbed by the land-based sinks and another 25% by the ocean [Table 1]. Absorption by natural sinks
raises the issue of net vs. gross emissions as basis for human accountability, as well as responsibility for
predicted sink saturation and sink decline due to anthropogenic activities. Indeed, the 4 per 1000 initiative
launched at COP21 in Paris in 2015 was based on the net emissions [Table 1]. Yet, agriculture contributes
about 14% (Grünberg et al.[2], 2010) and food systems (FSs) about one-third of anthropogenic greenhouse
gas (GHG) emissions (IPCC 2019; Balogh[3,4] 2019). Emission of GHGs from agriculture and FSs is
increasing because of an ever growing and progressively affluent human population. Success of the Green
Revolution technology since the second half of the 20th Century came at a cost of a significant
ecological/environmental footprint or EFP (Khan and Hanjra[5], 2009). Increase in global population at the
rate of about 1% per year, from 7.95 B in February 2022 to 9.7 B in 2050 and 11B in 2100 (U.N., 2019)[6], is
worrisome in terms of its EFP. In the context of Sustainable Development Goal (SDG) #2 of achieving Zero
Hunger by 2030, 691 M were food-insecure in December 2019 prior to COVID Pandemic and the number
increased to 820 M by December 2020 (FAO and UNICEF and WHO, 2021)[7]. It is widely argued that SDG
#2 will not be realized by 2030. Indeed, global food insecurity is a complex problem. Some perceive the
problem as not enough food and argue about the need to increase supply, while others believe the need for
reducing consumption and avoiding food waste and emphasizing the need to shift diets. It is apparent,
therefore, that achieving worlds sustainable FSs will necessitate simultaneous action on many fronts;
improved supply of nutritious food and reduced demand and waste (Röös et al.[8], 2017; Fanzo et al.[9], 2021;
von Braun et al [10], 2021). Thus, there is a strong need to reduce the environmental impact by reducing
GHG emissions from agriculture and FSs and by re-carbonization of the terrestrial biosphere. Yes, reducing
environmental impact by improving agriculture and transforming FSs are among the highest priorities for
limiting global warming to 2 0C, and advancing SDGs of the Agenda 2030 of the U.N. (U.N., 2015; Lal
et al.[11,12], 2021). Therefore, the objectives of this article are: (1) to review the degree to which various foot
prints reflect the key issues and response options; and (2) using CFP concepts, review priorities for action at
various levels of decision-making.
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
Page 3 of 19
Table 1. Historic carbon emission from land use and fossil fuel emissions (recalculated from Friedlingstein et al.[82] (2021)
1750-2020
PgC
1850-2021
1960-2020
2021
Land Use Change
235 ± 75
205 ± 65
80 ± 45
9.7 ± 0.5
Fossil Fuel
460 ± 25
465 ± 65
375 ± 20
0.8 ± 0.7
Total
690 ± 80
670 ± 65
455 ± 45
10.5 ± 0.9
Atmosphere
290 ± 5
270 ± 5
205 ± 5
4.2 ± 0.4
Ocean
180 ± 35
170 ± 35
115 ± 25
2.9 ± 0.4
Land
215 ± 50
200 ± 45
135 ± 25
3.3 ± 1
Imbalance
10
25
0
0.1
31.1
29.9
29.8
31.4
Source/Sink
I Source
II Sink
Land/Sink (% of total source)
INDICATORS OF ENVIRONMENTAL FOOTPRINT
Pertinent indicators of environmental impact of agriculture and FSs are parameters that reflect the direct
and indirect measures of resource consumption and adverse changes in quality and functionality of finite,
critical and fragile natural resources. Some important among these ecological indicators are quality of soil,
water, atmosphere or air, and biodiversity. Rather than being considered as factors of production, natural
resources can be considered as finite, fragile and non-renewable. Wiek & Tkacz[13] (2013) proposed the
concept of “ecological indicator” or EFP based on life cycle analysis for a wide range of products and
services, to signify ecological assets that a community needs and the natural resources it uses to produce the
essential goods and services and to absorb or dispose the waste or by-product. In relation to global warming
and anthropogenic emissions, therefore, EFP, comprising of all components including water and
biodiversity, is an indicator of GHG emissions in production of goods or services. This indicator, converted
to a carbon (C) equivalent for product and services for the entire life cycle from the cradle to grave is called
“carbon footprint” or CFP. The latter is a widely used in the public domain to address the threat of
anthropogenic climate change (Chen et al.[14], 2021). CFP, being the main component of EFP, may represent
more than 50% of the total EFP of an agricultural product (Balogh[4], 2019). However, the EFP comprises of
a range of components such as land (LFP), water (WFP), biodiversity (BFP), nitrogen (NFP), food (FFP),
resources (RFP) etc. [Figure 1]. The term CFP refers to a collective numerical value of all components of
EFP (e.g, LFP, WFP, BFP, RFP, FFP etc.) reported in terms of carbon dioxide equivalent (CO2eq). Thus, CFP
is widely used in the context of global climate change and identification of options for its mitigation and
adaptation.
Understanding the magnitude of CFP of agriculture and FSs, and factors affecting it, can lead to
identification of technological options which can enhance the use efficiency of inputs, reduce wastage, and
decrease the CFP.
The CFP includes total amount of all GHGs, including carbon dioxide (CO2), methane (CH4) and nitrous
oxide (N2O), emitted by an activity (e.g., agriculture, transport, landfill of waste) [Figure 2]. Specifically,
CFP encompasses the cumulative GHG emissions and there are different ways of expressing CFP such as at
level of an individual, community, organization, institution, or service. Principal sources of GHGs from
agriculture are N2O from soils through inputs of inorganic fertilizer and organic amendments (i.e., compost,
manure, biological nitrogen fixation), CH4 from enteric fermentation in ruminants and emission from rice
paddies (Röös et al.[15], 2014) and CO2 from land use conversion (e.g., deforestation, and diesel consumption
in farm operation) including tillage and drainage of wetlands for cultivation of upland crops. Assessing the
Page 4 of 19
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
Figure 1. Components of ecological footprint.
Figure 2. Carbon footprint of food products.
impact of agricultural drainage on increasing emissions of adjacent forest is a challenging issue which needs
to be addressed. Because the radiative-forcing or the global warming potential (GWP) of CH4 and of N2O is
higher than that of CO2, appropriate factors are used to convert emissions of all GHGs to CO2eq depending
upon an agreed timeframe (IPCC, 1996)[16].The GWP is a measure of the relative, globally-averaged
warming effect arising from the emissions of a particular GHG [Table 2].
Agricultural practices (e.g., tillage, fertilizer and pesticide use, farm operations, irrigation, harvesting, bailing
etc.) have different emission of CO2eq (Lal[17], 2004). Similarly, crop production and animal raising differ in
their GWP. Drainage and cultivation of peatland is the major cause of emission of GHGs. The calculated
GHG emissions of farm products, place or an activity over a specified period is needed to compute CFP. In
general, CFP is reported in the units of Kg CO2eq by converting CH4 and N2O into CO2equivalent.
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
Page 5 of 19
Table 2. Global warming potential of 3GHGs for different time horizons (adopted from (Ramaswamy et al.[83], 2001)
Time Horizon (Yr)
Gas
20
100
500
CO2
1
1
1
CH4
62
23
7
N2O
275
296
156
CFC11
6300
4600
1600
CFC12
10,200
10,600
5200
HCFC21
700
210
65
HCFC22
4800
1700
540
CFP can vary widely because of using different reference systems of the studies and differences in system
boundaries (Grünberg et al.[2], 2010). Therefore, standardization of the methodologies following the
international Standard (ISO) is critical to obtaining credible information for making sound decisions. Thus,
a wide range of CFP reported in the literature for the same product or service may be attributed to
differences in the complete or some parts of the value chain rather than that for the whole life cycle.
Choosing a different baseline, and different emission factors can also lead to differences in CFP for the same
product or service (Grünberg et al.[2], 2010).
PER CAPITA EMISSIONS
The global annual average per capita CFP differ among countries based on their economic development and
lifestyle. The national average per capita CFP (Mg CO2eq) varies widely and in 2020 is estimated at 15.52 for
USA, 7.38 for China and 1.91 for India with corresponding population of 323 million, 1.41 billion and 1.35
billion, respectively [Table 3]. The national average per capita CFP is higher for developed than developing
nations. The lowest per capita CFP at present is for countries in Sub-Saharan Africa followed by those in
South Asia [Table 3]. The global per capita CFP (Mg CO2eq) was 3.1 in 1960, 4.1 in 1970, 4.6 in 1980, 3.9 in
1990, 3.8 in 2000, 4.48 in 2010 and 4.48 in 2020 [Table 4], (World Bank, 2019)[18]. Tiseo[19] (2021) reported
that global average per capita CO2 emission dropped by about 7% in 2020 because of the disruptions by
COVID pandemic. There is also large variation in per capita CO2 emission among G20 nations. For 2020,
per capita CO2 emissions (Mg CO2/person. Yr.) in G20 countries in descending order was Saudi Arabia
(16.76), Australia (15.21),Canada (14.43), USA (13.68), South Korea (12.06), Russia (11.64), Japan (8.39),
China (8.19), Germany (7.71), South Africa (7.41), Italy (5.03), Turkey (4.83), United Kingdom (4.66),
France (4.26), Argentina (3.87), Mexico (3.04), Brazil (2.11), Indonesia (2.08) and India (1.74)
(Statista.com). Countries with the highest per capita CO2 emissions are Qatar (30.7), Kuwait (21.3),
Gibraltar (21.1) and Bahrain (19.9).However, the global average per capita CFP of 4.47 Mg CO2eq in 2020
must be reduced to < 2 Mg CO2eq by 2050 if the global warming is to be limited to 2 0C.
IMPORTANCE OF AGRICULTURE AND FOOD SYSTEMS IN CARBON FOOTPRINT
It is widely recognized that the present EFP of humanity is not sustainable. Through land use conversion for
agriculture and other anthropogenic activities, humanity has altered planetary processes by strongly
transforming the earth’s landscape, drastically increasing the resource use and generating a huge amount of
waste. Hoekstra & Wiedmann[20] (2014) observed that actual versus sustainable EFP of humanity was 18.2 vs.
12 B ha of land, 46-55 vs.18-25 Gt of CO2eq. per year, 1000-1700 vs. 1100-4500 B m3 of blue water, and 10.5
vs. 8.0 Mg/capita of material foot print. Hoekstra and Wiedmann also observed that humanity’s WFP (B m3
per year) was 6700 for green water and 1400 for gray water. Food and agriculture are the vital components
of human wellbeing and the heart of civilization that began with the onset of agriculture about 8000 BC.
Most religions and cultures celebrate agriculture and soil as a part of their heritage (Lal[21], 2013). Indeed,
Page 6 of 19
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
Table 3. Comparison of carbon foot print (Mg CO2eq/person/year) of 25 countries in sub-Saharan Africa, South and Central Asia,
Americas-Europe (adapted from Worldometer, 2022)[84]
Carbon Footprint (Mg CO2eq/person/yr)
Developing and developed Asia
Sub-Saharan Africa
Zimbabwe
0.72
Europe and Americas
Turkmenistan
14.0
Canada
18.58
Benin
0.60
Kazakhstan
13.01
Australia
17.1
Senegal
0.55
South Korea
11.85
USA
15.52
Ghana
0.51
Taiwan
11.72
Russia
11.44
Nigeria
0.44
Japan
9.70
Netherland
9.62
Ivory Coast
0.42
Malaysia
8.66
Germany
9.44
Cameron
0.40
Singapore
8.56
Finland
9.31
Kenya
0.33
China
8.19
Austria
8.43
Sudan
0.33
Iran
8.08
Belgium
8.34
Togo
0.31
Hong Kong
6.50
Ireland
8.32
Mozambique
0.21
Thailand
3.93
Norway
8.28
Tanzania
0.18
Uzbekistan
3.68
Poland
7.80
Liberia
0.18
Azerbaijan
3.50
Denmark
6.65
Sierra Leone
0.17
Bhutan
2.28
Italy
5.90
Uganda
0.13
Vietnam
2.20
Venezuela
5.89
Bukina Faso
0.13
Indonesia
2.03
U.K.
5.58
Madagascar
0.12
India
1.91
Spain
5.40
Rwand
0.12
Philippines
1.22
Hungry
5.23
Malawi
0.11
Kyrgyzstan
1.14
France
5.13
Chael
0.11
Sri Lanka
0.88
Switzerland
4.73
Ethiopia
0.10
Pakistan
0.87
Serbia
4.65
Nigel
0.10
Tajikistan
0.70
Argentina
4.61
Mali
0.09
Bangladesh
0.47
Sweden
4.54
Somalia
0.09
Cambodia
0.41
Mexico
3.58
DR Congo
0.08
Myanmar
0.31
Brazil
2.25
Nepal
0.29
Afghanistan
0.28
sustainable management of soil and agriculture are critical to achieving world peace and stability (Lal[22],
2015). Agriculture and FSs are also major consumer of natural resources. Presently, more than 40% of the
ice-free land is used for agriculture accounting for 3.75 B ha allocated for raising animals and 1.5 B ha for
growing crops. Further, 70% of all fresh water withdraw is used for irrigation. Despite being an issue that is
the heart of humanity, as documented by diverse religions and cultures (Lal[21], 2013; Lal[22], 2015),
agriculture and FSs also have their ugly side (hunger and malnutrition) which must be addressed. The latter
involves perpetuation of hunger and hidden hunger and adverse impacts of agriculture and FSs on
environment (e.g., soil, water, air and biodiversity).
FSs are complex and all-inclusive. The first step of FSs, growing crops and raising livestock, involves
agriculture, horticulture, forestry and fishery. In addition to growing food, other components of the FSs are
transporting, processing, distributing, using, preparing, consuming and disposing of the food waste. The
present FSs have severe limitations such as failing to end hunger and malnutrition, not being able to provide
adequate amount of safe and nutritious food to all people, and being responsible for degrading soils,
polluting water, aggravating global warming, dwindling biodiversity and denuding the landscape. Indeed,
one-third of all soils are degraded (FAO & ITPS, 2015; IPBES, 2019)[23,24]. Furthermore, emissions from FSs
Lal. Carbon Footprints 2022;1:3
Page 7 of 19
https://dx.doi.org/10.20517/cf.2021.05
Table 4. Temporal Changes in Global per Capita CO2 Emissions (Mg CO2 /Person (year) between 1960 and 2020 (World Bank, 2019,
Tiseo, 2021)[18,19]
Year
World bank
1960
3.12
Statista.com
3.05
1965
3.43
3.39
1970
4.15
4.03
1975
4.34
4.18
1980
4.60
4.37
1985
4.43
4.17
1990
3.90
4.27
1995
3.78
4.08
2000
3.81
4.11
2005
4.20
4.53
2010
4.48
4.79
2015
4.48
4.81
2018
4.48
4.80
2020
4.47
4.47 (COVID)
(production and supply chains) account for 25%-30% of all anthropogenic emissions (IPCC, 2019)[3], and
are increasing at the rate of 1% per year. Yet, prevalence of undernutrition affects 820 million and that of
malnutrition 2 billion people, and the ever increasing number of soil and climate refugees is threatening the
global peace and stability (Lal[22], 2015). Above all, the problem of inadequacy of FSs has been aggravated
through the disruptions in all components (both production and supply chain) caused by the COVID
pandemics (Lal et al.[25], 2020).
Being a major source of biomass for human needs, agriculture is a major factor affecting per capita national
[Table 3] and global [Table 4] CFP. Weinzettel et al.[26] (2019) evaluated potential net primary productivity
(NPPpot) of 186 agricultural crops in 236 countries, and found that human society appropriate 20% (13 Pg
C) of global NPP, which may increase with growing and increasingly affluent world population.
Of the total CFP, agriculture and FSs constitute a large component, especially in developing countries
[Table 3]. COP-26 in Glasgow (2021) identified five pillars to reduce CFP: (1) end waste; (2) use electricity
prudently; (3) adopt bioenergy for circular economy; (4) use hydrogen; and (5) sequester carbon (C). The
last pillar of C sequestration is important to agro-ecosystems, most of which are strongly depleted of their
terrestrial C reserves (Lal[27], 2018), and have a large potential to sequester atmospheric CO2 in biomass
(trees, forests, woodlands) and soil (Lal et al.[28], 2018). Sequestration of atmospheric CO2 in agroecosystems
is an important option to reduce humanity’s CFP.A wide range of agricultural factors play an important role
in CFP of agriculture production. Balogh[4] (2019) argued that CFP of agriculture depends on economic
development and agricultural production such as arable land, agricultural machinery, fertilizer use,
irrigation, and other inputs. Therefore, the strategy of reducing CFP of FSs is to identify factors affecting
productivity and use-efficiency of agriculture, and to identify site-specific technological options, based on
recommended and science-based proven practices, which can reduce the CFP of food products and other
related commodities.
FACTORS AFFECTING CFP OF AGRICULTURE
The global FSs vary widely from production of chemicals (e.g., fertilizers, pesticides) and seed to food
packaging, and diverse agronomic systems such as with or without tillage, irrigation, chemicals, residue
Page 8 of 19
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
retention, and genetically modified organisms (Lal[17], 2004a). Fertilizer use has drastically increased in Asia
and Latin America. Total and rate of fertilizer use in India from 1950 to 2020 in Table 5 indicate drastic
increase. Similar trends are observed in China, Brazil and elsewhere in emerging economies. Thus, treating
soil as a factor of production or a finite resource, and crop residues as a resource or waste can make a strong
difference in CFP. Developing methods for credible estimation of the CFP is important to identifying
policies for promoting those food/agricultural systems which have low and discouraging those which have a
high CFP. Such understanding is critical to making the environment-friendly choices in lifestyle of a
community, region or a nation. Components of the life cycle analysis for FSs may include raw material
acquisition (e.g., land, chemicals, energy for farm operations, irrigation water lift and application),
processing, packaging, storage, transportation, consumption, along with disposal of food waste (Xu et al.[29],
2015). The CFP can be computed on the basis of footprint weight, sustainability measures, and % daily value
(Leach et al.[30], 2016). It comprises of direct and indirect emissions of GHGs. Direct emissions are those
GHGs which are released at each step of the process and indirect are CO2eq emissions caused by energy
consumption in each process (Wu et al.[31], 2013). Identification and quantification of these components of
CFP, outlined in Figure 1, is essential to developing strategies of optimizing the CFP. Thus, there is a need
to develop methodology that permits assessment of foot print of diverse entities (e.g., water, biodiversity)
into common units. Assessing footprint of each component is essential to developing strategies of reducing
CFP and advancing practices which lead to sustainable development based on ecological principles of
production and consumption.
CARBON SEQUESTRATION FOR REDUCING CFP OF A PRODUCT OR SERVICE
Carbon capture and storage (CCS) in soil and vegetation is called terrestrial sequestration. CCS in terrestrial
ecosystems is a natural process and is based on the removal of atmospheric CO2 by photosynthesis and
retention of biomass-C in soil and vegetation so that it is not re-emitted into the atmosphere but is retained
in the terrestrial ecosystems for a longtime. In this context, a primary goal of sustainable systems of soil,
crop, tree and livestock management is to protect, restore and manage the terrestrial C stocks so as to
enhance or prolong their mean residence time (MRT). In this context, CCS in soil and vegetation involves
different processes than those involved in CO2 injection into stable geological strata. The latter comprises of
C capture from point sources (e.g., chimney of a coal-fired power plant, ethanol production from corn
grains) and injection into stable and impermeable geological strata, old coal seams, oil wells or saline
aquifers. CCS in land-based sinks is a natural process, based on photosynthesis and secure storage of
biomass -C (above and below ground), soil organic C (SOC), and soil inorganic C (SIC) with a long MRT
(Lal[17], 2004; 2010; Lal, et al.[32], 2021). Indeed, C sequestration in global cropland production is considered a
viable option to reduce GHG emission while producing nutritious food for the growing human population
(Lu et al.[33], 2018).
CARBON FOOTPRINT OF CROPS AND CROPPING SYSTEMS
Global arable land use, comprising of 1500 million hectare (M ha) has a strong impact on CFP of
agriculture. Thus, improving cropping systems can reduce emission of GHGs from soil and farming
operations. Total GHG emission from cropping systems involves all farm operations e.g., seedbed
preparation, application of fertilizers (e.g., Table 5 for India) and pesticides, irrigation, harvesting, grain
drying, etc. There are large hidden C costs of all inputs such as fertilizers, herbicides, pesticides) (Lal, 2004a).
CFP also involves emission from decomposition of straw and roots, and those from mineralization of soil
organic matter (SOM) (Lal[17], 2004a).
The CFP of agroecosystems is affected by increasing use of inputs such as fertilizers, pesticides, tillage and
irrigation. Millar et al.[34] (2014) reported that in crop production,75% of total emissions are attributed to N
Lal. Carbon Footprints 2022;1:3
Page 9 of 19
https://dx.doi.org/10.20517/cf.2021.05
Table 5. Fertilizer (N + P2O5 + K2O) use in India and the world (FAO, 2021)[85]
India
Total (Mt/yr)
World
India
Rate (kg/ha)
World
1950
0.069
-
0.49
-
-
1960
0.294
30.9
1.93
30.85
0.95
6.26
1970
2.257
68.61
13.61
68.61
3.29
19.84
1980
5.517
115.79
31.95
115.79
4.76
27.59
1990
12.539
136.95
67.55
136.95
9.16
49.32
2000
16.702
134.75
90.12
134.75
12.39
66.88
2010
28.124
173.76
141.93
173.76
16.18
81.88
2015
25.58
184.01
135.76
186.02
13.90
73.00
2018
27.2
194.39
160.8
120.9
14.5
133.0
2019
29.4
198.10
173.5
122.9
15.4
141.2
2020
32.512
201.66
161.01
188.52
16.1
85.4
Year
Total
India as % of World
Rate
-
The data in this Table was collated with the help of IFDC, Muscle Schoals, AL.
fertilizer use (both organic and inorganic). Use of N fertilizer affects CFP from production, application and
direct emission of N2O from soil following application of fertilizers. Millar et al. (2014)[34] also argued that
once N is accounted for, there are no differences among organic, integrated, or conventional farming
practices. Therefore, optimizing the use efficiency of inputs and enhancing productivity can spare the land.
Vittis et al.[35] (2021) reported that the LFP of agroecosystems can be reduced by closing the yield gap,
optimizing fertilizer inputs, and allocating 16 major crops across the global cropland. Vittis and colleagues
estimated that global cropland area can be reduced by 50% of its current extent (1500 M ha) and spared land
returned back to nature. Among numerous ecological benefits, the spared cropland would provide space for
terrestrial C sequestration in soil and vegetation.
It is a high priority to reduce humanity’s LFP by optimizing the land use and returning some land back to
nature (Lal[27], 2018). Sparing current forests from conversion is an effective strategy, but can only happen if
adequate livelihood options are available to those involved in agricultural horizontal expansion.
Furthermore, closing yield gaps may not always lead to closing efficiency gaps. For example, optimizing or
minimizing CFP by managing rate of N fertilization in some crops may differ from economic
mineralization.
AGRICULTURAL MANAGEMENT PRACTICES TO REDUCE CARBON FOOTPRINT
Adoption of site-specific and science-based and sustainable management practices are critical to reducing
CFP of agriculture/FSs, and leading to adaptation and mitigation of climate change, reducing per capita
land use, and attaining the operating space within the planetary boundaries (Rockström et al.[36], 2009). In
addition to reducing emission from crop production, GHG emission from agroecosystems can be off- set by
sequestration of C in soil as SOC and SIC. Some examples given below indicate the options of reducing CFP
by using science-based management practices. Liu et al.[37] (2018) estimated the gross CFP of crop
production in China from 2000 to 2015 at 133 Tg of CO2eq per year. However, soil C sequestration was
estimated at 25 Tg CO2eq per year, and thus, the net CFP for crop production in China was 108 Tg of CO2eq
per year. Liu and colleagues also observed that the farm CFP in China decreased by 9% because the
proportion of crop residue retention increased by 26.4% and the improved use efficiency of N fertilization
which also decreased the rate of input of N fertilizer by 8.4 Kg N/(ha.yr).
Page 10 of 19
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
In India, total amount and rate of fertilizer use increased drastically between 1950 and 2020 [Table 5].Thus,
emission from agriculture sector have increased since 1950s, partly because of low use efficiency of
fertilizers (such as N) and unbalanced use of fertilizers. Sah and Devakumar[38] (2018) reported that
emissions have increased 161% from 14.81 Tg Ceq /yr (0.12Mg C eq/(ha.yr) in 1960 to 38.71 Tg Ceq (0.28
Mg Ceq/(ha.yr)) in 2010.This increase is attributed to decrease in area of less C-intensive coarse cereals and
22% increase in rice cultivation. Among crops, emission was 23.71 Tg Ceq for rice compared with 2.98 Tg
Ceq for red gram. Emission of N2O and CH4 were the major contributors.
Rather than sequestration, conversion of natural to agricultural ecosystems can lead to loss of soil C pool.
For example, a study on the impact of land use conversion was conducted for the
U.S. Western Corn Belt by Lu et al.[33] (2018). In comparison with the baseline period of 1980-2005, Lu
et al.[33] found that cropland expansion more than tripled in 2006-2016, and the resultant land use change
led to soil C loss of 90.5 ± 14.7 Tg C. Thus, grain production in this region changed from C neutral to C loss
of 2.3 Kg C/kg of grain produced. Conversion of C-rich soils from natural to agro-ecosystems can lead to a
negative C budget and increase the CFP. On the contrary, adoption of bioeconomy can reduce emissions
and also reduce CFP. For example, a study in EU by O’Brien et al.[39] (2015) evaluated CFP of EU-27 for the
period of 2000 to 2011, and found that promotion of bioeconomy decreased the LFP by 1% annually
reaching 0.29 ha/capita by 2011. O’Brien and colleagues suggested that bioeconomy could decrease per
capita cropland at the rate of 2%per annum and achieve the safe operating space within planetary
boundaries by 2030.
Cropping systems, based on cover cropping and use of legume-based rotations can also reduce CFP. Based
on a study for determination of CFP of durum wheat (Triticum tugidum) in Saskatchewan, Canada, Gan
et al.[40] (2011) observed that decomposition of crop straw accounted for 25% of total emissions; those from
production, transportation, storage and delivery of (Gan et al.[40], 2011) fertilizers and pesticides to farm
gates and their application 43%, and emission from other farming operations 32%. Gan and colleagues also
observed that the durum wheat grown in rotation with an oilseed crop (Brassica spp.) had CFP of 0.33 kg
CO2eq /kg of grain that was 7% lower than the cereal-cereal durum system. The CFP of durum was lowered
by 17% when it was grown in rotation with N-fixing pulse crop, and by 34% in pulse-pulse-durum system
(0.27 kg CO2eq/kg of grain). These studies raise questions on the accounting system boundaries used. For
example, if straw decomposition is counted as a loss, it may be based on the assumption that aboveground
productivity is counted as a “sequestration”. Therefore, it may be appropriate to use IPCC national
accounting standards. It is also essential to develop a rule for partitioning system-level emissions to
component crops.
Importance of crop rotations and residue management to reducing CFP of cropping systems has been
reported in several studies. These practices are also called climate smart agriculture (FAO, 2013)[41].
Brankatschk and Finkbeiner[42] (2017) reported that ignoring crop rotation would lead to underestimation of
the annual GHG savings of EU-28 rapeseed biodiesel by 1.67 TgCO2eq .Thus, they argued that crop rotations
and straw harvest must be considered for the product CFP of bread, milk and first and second generation of
biofuels, and these recommendations are relevant to all regions of the world.
In addition to cereals, soybean is an important crop as a source of protein, and oil. Castanheira and Freire[43]
(2013) observed large variation in CFP of soybean ranging from 0.1 to 17.8 kg CO2eq/kg of soybean
depending on original land use and soil/crop management. The highest GHG emissions were calculated for
tropical moist region when rainforest is converted to soybean cultivation. Without considering the land use
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
Page 11 of 19
conversion, CFP varies from 0.3-0.6 Kg CO2eq/kg of soybean. Furthermore, all mechanical tillage systems
have more GHG emission than a no-till (NT) system, and N2O emission is an important factor affecting
CFP.
Horticultural crops (e.g., vegetables) have a different CFP than cereals and other crops because of
differences in farm operations and in inputs. In rapidly urbanizing China, Hu et al.[44] (2019) estimated the
CFP of urban agriculture in Beijing with the focus on vegetables. Based on production, transportation and
distribution of 1 kg of fresh vegetables, Hu and colleagues estimated the CFP (CO2eq/kg of fresh vegetables)
at 0.318 for conventional and 0.624-0.652 for home delivery systems.
TILLAGE SYSTEMS AND CFP OF CROPPING SYSTEMS
Global adoption of conservation agriculture (CA) is gaining momentum [Table 6]. Land area under CA is
estimated at about 180 M ha or about 12.5% of global crop land (Kassam et al.[45], 2019), and it is widely
adopted in South America (e.g., Brazil, Argentina, Chile, Paraguay ), and is also gaining popularity
elsewhere. Among numerous merits of a system-based CA are soil and water conservation, reduction in use
of energy for farm operations, and in saving of time in establishing a second crop with a short time between
harvesting one crop and seeding the second crop such as in the case of rice-wheat system in the IndoGangetic Plains of South Asia. A system-based CA can enhance use efficiency of inputs, sustain agronomic
productivity and lead to sequestration of SOC in the surface layers (Lal[22], 2015; Lal et al.[46], 2017). Above
all, conversion of plow-based tillage to NT-based CA can lead to saving in energy needed to perform
primary and secondary tillage operations [Table 7]. Thus, CFP of a cropping system can be drastically
reduced by conversion of conventional tillage to CA and saving in fertilizers and pesticide use through
adoption of integrated soil fertility management, integration of pest management, and integration of crops
with trees and livestock (Lal[25], 2020).The latter involves complex systems such as agro-pastoral, silvopastoral, agri-silvo and agro-silvo-pastoral systems (Okigbo & Lal[47], 1977; Nair et al.[48], 2009; Rosenstock
et al.[49], 2019).
With tillage and inputs being important determinant of CFP of cropping systems, use of precision
agriculture technology (PATs) can also impact the magnitude of CFP by savings of inputs (Brown et al.[50],
2016). Adoption of PATs in conjunction with CA and drip sub-fertigation can reduce CFP.
PLANTATION AND HORTICULTURAL CROPS
Similarly to cropland, coffee and horticultural crops also have a large CFP. Ratchawat et al.[51] (2020)
reported CFP (kg CO2eq/kg) of Robusta coffee products at 0.40 ± 0.12 of coffee cherry, 0.55 ± 0.08 for roasted
coffee and 0.56 ± 0.08 for ground coffee. Ratchawat and colleagues estimated that almost 70% of all GHG
emission came from chemical fertilizers involving both production and application. WFP (m3/kg) was 10 for
coffee cherries and 27 for roasted and ground coffee. Based on the data from 116 coffee farms in five Latin
American countries, van Rikxoort et al.[52]2014) evaluated CFP of four production systems: (1) traditional
polyculture; (2) commercial polyculture; (3) shaded monoculture; and (4) unshaded monoculture. Rikxoort
and colleagues found that polycultures have a lower mean CFP of 6.2-7.3 Kg CO2eq/kg of parchment coffee
than monocultures of 9.0-10.8.kg.It was also found that traditional polycultures have a much higher C stock
in the vegetation at 42.5 Mg/ha than the unshaded monoculture of 10.5Mg/ha. Martins et al.[53] (2018)
computed the CFP of Brazilian coffee production from 2004-2005 to 2014-2015. Based on data of plantation
area and coffee production, Martins and colleagues estimated that CFP and WFP were 19.79 Tg CO2eq and
49284 M m3 of water, respectively. Martins and colleagues computed CFP for total resource use and impacts,
which differs than the way it is defined in this article as footprint per unit of product or human activity.
Page 12 of 19
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
Table 6. Global adoptions of conservation agriculture (adapted from Kassam et al.[45], 2019)
Region
Global Cropland Area Under CA (106 ha)
South America
69.90
North America
63.18
Australia and NZ
22.67
Asia
13.93
Russia + Ukraine
5.70
Europe
3.56
Africa
1.51
Total
180.44
Practiced on 12.5 % of global cropland area.
Table 7. Carbon emission from diesel consumption for different tillage operations, fertilizers and pesticide use (adapted from Lal[17],
2004)
I
II
III
Farm operations
Carbon footprint
Units
Tillage Sub-soiling
11.3 ± 2.8
Kg Ceq/ha
Moldbourd Plowing
15.2 ± 4.1
Chisel Tillage
7.9 ± 2.3
Heavy Disc Plowing
8.3 ± 2.5
Chisel Tillage
4.0 ± 1.9
Heavy Disc Plowing
8.3 ± 2.5
Field Cultivation
4.0 ± 1.9
Rotary hoeing
2.0 ± 0.9
Fertilizer Nitrogen
1.3 ± 0.3
Phosphorus
0.2 ± 0.06
Potassium
0.15 ± 0.06
Lime
0.16 ± 0.11
Pesticides Herbicides
6.3 ± 2.7
Insecticides
5.1 ± 3.0
Fungicides
3.9 ± 2.2
Kg Ceq/ Kg nutrient
Kg Ceq/ Kg a.i.
LIVESTOCK MANAGEMENT
Livestock are an important component of agriculture, especially in case of small land holders and resourcepoor farmers. In comparison with crops, livestock management is resource-intensive and requires high
energy, water, land, nutrient and infra-structure investment. Therefore, it is important to identify practices
of sustainable management of livestock, and is also critical to educate the consumer about judicious use of
animal-based products (i.e., meat, dairy). Globally, livestock sector is estimated to account for 15% of GHG
emission, 80% of these emissions originate from ruminant animal systems involving enteric fermentation
and manure management (Persson et al.[54], 2015). Thus, emissions from livestock sector have raised
numerous questions regarding the possibility of reducing animal-based diet as a strategy to reduce emission
of GHGs.
Livestock is an important component of India’s agriculture sector. In 2012, India’s livestock sector produced
304,31 and 4 Tg in CO2eq of enteric CH4, manure CH4,and N2O, respectively (Patra[55], 2017). The relative
contribution (% of total) of different species to GHGs was 55, 37, 4, 2.1 and 1 for cattle, buffalo, sheep, goat,
pig and other animals, respectively. Enteric fermentation was the major contributor and accounted for
89.7% of the total emissions from India’s livestock sector followed by manure CH4 (9.2%) and N2O (1.2%).
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
Page 13 of 19
The CFP (Kg CO2eq/kg of the produce) was estimated at 1.21 for cross-bred cattle to 2.96 for indigenous cattle.
In Southern Australia, Ridoutt et al.[56] (2014) estimated the land area footprint of beef cattle. The land area
needed (m2/kg of live weight) ranged from 86 to 172. Ridoutt and colleagues observed that these results
were approximately 10 and 1000 times the normalized carbon and water scarcity footprint data, and
highlight the importance of taking into account the land quality in the calculation of LFP.
In Mato Grosso, Brazil, Cerri et al.[57] (2016) assessed CFP of cattle farming for beef production. Evaluating
22 farms with cumulative pastureland area of 60,000 ha, Cerri and colleagues observed that the largest
source (89%-98%) of GHG in extensive beef production is contributed by animals. Of these, 67-79% come
from enteric fermentation followed by those from manure (20%-33%).Other sources of emission were
agricultural inputs and energy. The CFP of a farm with herd size of 2000 cattle was 4.8-8.2 kg CO2eq per kg
of the liveweight gain. For farms raised animals, CFP ranged from 5.0 to 72 kg of CO2eq per kg of the live
weight gain. Therefore, herd size and management to reduce enteric fermentation are critical to reducing
CFP of beef cattle. Rojas-Downing et al.[58] (2018) studied a representative farm based on grazing dairy
practices in the state of Michigan, USA, and proposed a food footprint (FFP). Using FFP, Rojas-Downing
and colleagues identified a most sustainable milk production level (8618 kg of milk per cow per year) which
was 19.4% more than the average milk production (7215 kg per cow per year).
Furthermore, most sustainable pasture composition for the state of Michigan was found to be 90% for
tall fescue with 10% for white clover. Thus, there is a strong need for identification of site-specific
management and production standards. Yan et al.[59] (2013) evaluated GHG emissions from pasturebased milk production using fertilizer N or white clover at a research farm in Ireland between 2001
and 2006.The white clover based system had 11 to 23% lower CFP than fertilizer N system (0.86-0.87
vs. 0.97-1.13 kg CO2eq/kg of energy-corrected milk). Furthermore, emissions of both N2O and CO2 were
lower in white clover system but those of CH4 were similar in both systems.
Because of its large foot print (LFP, WFP, CFP, FFP etc.), there is a strong need for development of a
climate-neutral livestock production system .Thus, Ridoutt[60] (2021) proposed a radiative-forcing (RF)
based livestock production system. Based on Australian sheep production for meat. Rideout reported that
RF plateaued at 0.64 mV/m2, and is projected to decrease with better management. The new RFbased assessment of livestock may be adopted by the ISO for aligning food system with the Paris Accord.
OPTIMIZING HUMAN DIET FOR ADDRESSING CFP OF AGRICULTURE
The food system, being a major contributor to anthropogenic emissions (Röös et al.[15], 2014), must be
critically assessed with regards to the source of GHGs [Figure 2]. Primary GHG involved in FSs are CO2
from deforestation, land use conversion, plowing, and erosional processes [Figure 2]. Erosion-induced
transport of SOC can be a major source of all three gases (Lal[12], 2004; Lal et al.[61], 2021a; Lal et al.[32], 2021).
N2O is primarily contributed by soil through use of inorganic and organic fertilizers. CH4 is contributed
from livestock and rice paddies and wetlands [Figure 2]. The U.N. FSS of 2021 identified some specific
strategies to advance SDGs or the Agenda 2030 of the United Nations (Lal et al.[12], 2021). The
environmental footprint of the diet of 7.8 billion people, projected to be 9.7 B by 2050 and 11 B by 2100
(U.N., 2019)[6], is an important factor to sustainable management of soil and water resources but also to
addressing the issues of global warming along with quality and renewability of water resources. Leach
et al.[30] (2016) reported that the EFP of food production spans multiple dimensions including CFP based on
GHG emission, nitrogen footprint (NFP) and water use (both green and blue, WFP), and land use (LFP). It
is, thus, important to identify diet that can minimize each of these FP values, especially those diets which
have synergies rather than tradeoffs among different low FP diets.
Page 14 of 19
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
Beef production has received a considerable attention because of its high EFP (e.g., CFP, NFP, WFP, LFP).
Buratti et al.[62] (2017) reported that organic systems (Kg CO2eq/kg of live weight) is 24.62 compared with
18.21 for the conventional systems because enteric fermentation is the primary factor in GHG emission with
a range of the global CF value. Ibidhi and Ben Salem[63] (2020) computed WFP of a wide range of livestock,
and reported that WFP of meat is higher than that of either milk or eggs. Ibidih and Salem reported that
WFP of beef is much larger than WFPs from sheep, goat, pork and chicken. These differences in WFP are
attributed to differences in the food conversion ratio among animals. Most ruminants (e.g., cattle, sheep and
goat) have a poor food conversion ratio than those of the monogastric animals (e.g., poultry and swine).
Similar to beef production, milk production has also attracted a lot of attention. Velarde-Guillen et al.[64]
(2022) reviewed CFP of milk production in Latin America. The range of CFP observed in the Latin
American region was 1.54 to 3.57 kg CO2eq /kg of fat and protein corrected milk. Velarde-Guillen et al.[64]
(2022) observed that, in Latin America, cattle system and region have a more significant impact on milk
CFP than the feeding management (e.g., zero-grazing, semi-confinement, and pasture).
Espinoza-Orias et al.[65] (2011) estimated the CFP of one loaf of slice bread (800 g) consumed at home on the
basis of several parameters such as country of origin of wheat, type of flour, and type of packaging. The
lowest CFP was observed for the whole wheat thick sliced bread wrapped in a plastic bag, and the highest
for the wheat bread packed in a paper bag. Further, CFP could be reduced by 25% by avoiding toasting and
refrigerated storage of bread.
Conventional vs. organic farming is another important factor affecting CFP of bread. Treu et al.[66] (2017)
computed the CFP of conventional vs. organically grown food products. Treu and colleagues observed that
CFP of the conventional vs. organic diets are essentially similar at ~1250 kg CO2eq per capita per year.
However, the land area use to provide food is 40% greater for organic vs. conventional diet at 1900 and 2750
m2 of land per capita per year, respectively. Furthermore, the average conventional diet contains 45% more
meat and organic diet 40% more vegetables, fruits and legumes (combined). Treu and colleagues also
observed that animal-based food products dominate the CFP in both diets and land use and accounts for 70
to 75% of CFP in both diets. Treu et al.[66] concluded that diet-related CFP can be reduced by shifting
towards diets with less animal-based food products, and there is not much difference in CFP among organic
vs. conventional system of food production.
FOOD WASTE AND CFP OF AGRICULTURE
Agriculture is a resource-intensive enterprise and a lot of resources are consumed in agroecosystems (e.g.,
soil, water, energy, chemicals). Avoidable food waste incurs loss of resources with adverse impacts on
environment. World wastes 1.4 Gt of food every year. Globally, as much as 931 Mt of food is wasted from
retail, food service and household, and it is enough to feed 820 M food-insecure people (Pearson[67], 2021).
The U.N. SDG #12.3 is aimed at reducing the food waste by 50% by 2030. (U.N., 2015)[11]. Food waste varies
among nations, and the U.S discards food more than any other country (40 Mt). This is 30 to 40 % of the
entire food supply and is equivalent to 99.3 kg/per person per year (RTS, 2020)[68]. Food waste in the U.S.
comprises 22% of all municipal solid waste. Yet, a large number of population is also food-insecure. As
many as 35 M people in the U.S. were food insecure prior to COVID 19, and the number of persons
vulnerable to food insecurity has increased to 50 M in 2022 (RTS, 2022)[69]. In the U.S., Economic Research
Service estimated that for the baseline year of 2010 the food loss was 31% of food supply, equaling 133
billion pounds (523 billion kg) at an estimated value of $161.6 billion. The 2030 SDGs aim to cut food loss at
the retail and consumer level by half to 66 billion pound (261 billion kg), (EPA, 2016)[70]. Reutter et al.[71]
(2017) estimated that Australian food waste represents 9% of total water use and 6% of GHG emissions.
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
Page 15 of 19
Based on a case study on U.K., Tonini et al.[72] (2018) estimated the global warming impact of the avoidable
food waste at 2000 to 3600 kg CO2eq per Mg of food waste. Schott and Cánovas[73] (2015) estimated from a
study in Sweden that an average of 35% of household food waste can be avoided, which will reduce GHG
emission of 800-1400 kg of CO2eq per Mg of food. Wasted food represents a high magnitude of energy,
nutrient and virtual water rich stream with adverse effects on environment and resource use. In China, Song
et al.[74] (2018) estimated average food waste at 12-33 kg per capita per year. With a CFP of 30-96 kg CO2eq
per capita per year. Song and colleagues also observed that animal-based food accounts for 5%-18% in
weight but 18%-40% in CFP because of the extra resources involved in animal-based food. A thorough
understanding of economic and ecological costs involved of the food wasted is essential.
Therefore, reducing food waste, estimated at ~30% of food produced globally, can drastically decrease the
CFP of agroecosystems. Globally, food waste contributes 11% (3.3 Gt of CO2eq) of all GHG emissions: 43% at
home, 40% at restaurants,16% at farms and 2% at manufacturers (RTS 2022)[69]. If food waste is a country, it
is the 3rd largest emitter of GHGs after China and U.S. The resource impact of food waste can drastically
influence the CFP and must be accounted for especially in limited resources such as energy, water and
prime agricultural land. In India, Kashyap & Agarwal[75] (2020) estimated total food loss in harvest and postharvest stages for the food supply chain for some selected food items. They reported that food losses
amounted to 58.3 ± 2.22 M Mg in 2013 with the highest losses in sugarcane and rice with a large loss of
water resources. LFP and CFP associated with food loss were estimated at 9.58 ± 0.4 M ha and 64.1 ± 3.8 Tg
CO2eq, respectively, with rice contributing substantially to both. In 2010, U.S. EPA estimated that food waste
accounted for nearly 14% of total solid wastes (Golan[76], 2013). Nonetheless, a significant gap exists in the
understanding of the food waste implications of the rapidly developing economies (Parfitt et al.[77], 2010).
The food-energy-water-soil or the FEWS nexus (Lal et al.[46], 2017) is an important concept to assess the
impact of food waste on CFP. Kibler et al.[78] (2018) characterized food waste on the FEW when food
produced is not consumed by human or animals. Kibler and colleagues observed that different food waste
management options (e.g., landfilling, composting, anaerobic digestion, incineration, waste prevention)
provide diverse pathways to manage CFP. These researchers proposed a “food-waste-system” approach to
optimize resources and reduce the CFP.A similar approach was adopted by Sarker et al.[79] (2016) who
proposed a conceptual methodology for characterizing inter-connected FEW components.
Because of large differences in RFP of foods, there are several options for the general public to modify
lifestyle and make it more sustainable. Schanes et al.[80] (2016) proposed a novel framework for consumers to
lower their CFP with the focus on food consumption.
SAVING LAND AND NATURAL RESOURCES BY AVOIDING FOOD WASTE
Global food waste aggravates global warming, and depletes the finite natural resource base while also
polluting the environment. It is equivalent to 2.2 Gt of CO2eq of CFP in terms of GHG emissions. The per
capita food wastage CFP ( Kg CO2eq/per person per year ) is estimated by (FAO, 2014)[81] at 860 for North
America and Oceania, 810 for industrialized Asia, 680 for Europe, 540 for Latin America, 350 for North
Africa and West Asia, 350 for South and South East Asia, and 210 for Sub-Saharan Africa (FAO,2014)[81].
The equivlent WFP is shown in Table 2, and the world average WFP for food waste is 38 m3/capita per year
(FAO, 2013)[41].The food waste represents 4.4 M Km2 of land area on which food is produced and lost each
year. This land area is larger than that of the Indian Sub-Continent (Pearson[67], 2021). Therefore, humanity
must create a future where both nature and people thrive, flourish and live in harmony with one another.
Page 16 of 19
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
CONCLUSION
Humanity’s unsustainable footprint is likely to increase with growing and progressively affluent world
population. Humanity’s impact on planetary processes, referred to environmental or ecological footprint,
comprises of a range of sub-components (i.e., land, water, energy, fertilizers, nitrogen, biodiversity).
EFP, and more specifically CFP, can vary widely because of using different reference systems of the studies
and differences in system boundaries. Therefore, standardization of the methodologies following the ISO is
critical to obtaining credible information for making sound decisions.
Humanity’s CFP can be reduced by making appropriate choices in food systems including production and
supply chains, changing lifestyle and dietary preferences, and using agricultural systems which narrow the
yield gap and can produce more from less.
The global warming impact of the avoidable food waste at 2000 to 3600 kg CO2eq per Mg of food waste.
Globally, as much as 931 Mt of food is wasted from retail, food service and house hold, and it is enough to
feed 820 M food-insecure people. Food waste, a heinous crime against nature, is not acceptable.
DECLARATIONS
Authors’ contributions
The author contributed solely to the article.
Availability of data and materials
Not applicable.
Financial support and sponsorship
None.
Conflicts of interest
The author declared that there are no conflicts of interest.
Ethical approval and consent to participate
Not applicable.
Consent for publication
Not applicable.
Copyright
© The Author(s) 2022.
REFERENCES
1.
2.
3.
4.
Lal R, Brevik EC, Dawson L, et al. Managing soils for recovering from the COVID-19 pandemic. Soil Syst 2020;4:46. DOI
Grünberg J, Nieberg H, Schmidt T. G. Carbon footprints of food: a critical reflection. Landbauforsch. Available from:
https://www.researchgate.net/publication/288777178_Carbon_footprints_of_food_A_critical_reflection [Last accessed on 14 Apr
2022].
IPCC. Climate change and land: an IPCC special report on climate change, desertification, land degradation, sustainable land
management, food security, and greenhouse gas fluxes in terrestrial ecosystems. Available from: https://philpapers.org/rec/SHUCCA-2
[Last accessed on 13 Apr 2022].
Balogh J. M. Agriculture-specific determinants of carbon footprint. Available from: http://real.mtak.hu/105131/1/Studies-121-3Balogh.pdf [Last accessed on 13 Apr 2022].
Lal. Carbon Footprints 2022;1:3
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
https://dx.doi.org/10.20517/cf.2021.05
Page 17 of 19
Khan S, Hanjra MA. Footprints of water and energy inputs in food production-global perspectives. Food Policy 2009;34:130-40. DOI
U.N. World population prospects 2019: Highlights (ST/ESA/SER.A/423). Available from:
https://population.un.org/wpp/publications/files/wpp2019_highlights.pdf [Last accessed on 13 Apr 2022].
FAO I, UNICEF and WHO. The state of food security and nutrition in the world 2020. Transforming food systems for affordable
healthy diets. Available from: https://www.fao.org/publications/card/zh/c/CA9692EN/ [Last accessed on 13 Apr 2022].
Röös E, Bajželj B, Smith P, Patel M, Little D, Garnett T. Greedy or needy? Global Environmental Change 2017;47:1-12. DOI
Fanzo J, Haddad L, Schneider KR, et al. Viewpoint: rigorous monitoring is necessary to guide food system transformation in the
countdown to the 2030 global goals. Food Policy 2021;104:102163. DOI
von Braun J, Afsana K, Fresco L.O, Hassan M, Torero M. Food system concepts and definitions for science and political action.
Available from: https://www.nature.com/articles/s43016-021-00361-2 [Last accessed on 13 Apr 2022].
U.N. Transforming our world: the 2030 agenda for sustainable development, united nations summit on sustainable development.
Available from: https://stg-wedocs.unep.org/bitstream/handle/20.500.11822/11125/unepswiosm1inf7sdg.pdf?sequence=1 [Last
accessed on 13 Apr 2022].
Lal R, Bouma J, Brevik E, et al. Soils and sustainable development goals of the United Nations: An International Union of Soil
Sciences perspective. Geoderma Regional 2021;25:e00398. DOI
Wiek A, Tkacz K. Carbon footprint: an ecological indicator in food production. Available from:
https://www.semanticscholar.org/paper/Carbon-footprint%3A-an-ecological-indicator-in-food-Wi%C4%99kTkacz/c332c4c4e5a4154f680fc90d50bbb643f695b390 [Last accessed on 13 Apr 2022].
Chen R, Zhang R, Han H. Where has carbon footprint research gone? Ecological Indicators 2021;120:106882. DOI
Röös E, Sundberg C, Hansson P. -A. Carbon footprint of food products. In: Muthu, S.S. (Ed.), Assessment of carbon footprint in
different industrial sectors, Vol 1. pp. 85-112. Available from: https://link.springer.com/chapter/10.1007/978-981-4560-41-2_4 [Last
accessed on 13 Apr 2022].
IPCC. Climate change 1995: the IPCC second assessment report. Scientific-technical analysis of impacts, adaptations, and mitigation
of climate change. Available from: https://www.ipcc.ch/report/ar2/wg2/ [Last accessed on 13 Apr 2022].
Lal R. Carbon emission from farm operations. Environ Int 2004;30:981-90. DOI PubMed
World Bank. CO2 emissions (metric tons per capita). Available from: https://data.worldbank.org/indicator/EN.ATM.CO2E.PC [Last
accessed on 13 Apr 2022].
Tiseo I. Historical carbon dioxide emissions from global fossil fuel combustion and industrial processes from 1750 to 2020. Available
from: https://www.statista.com/statistics/264699/worldwide-co2-emissions/ [Last accessed on 13 Apr 2022].
Hoekstra AY, Wiedmann TO. Humanity’s unsustainable environmental footprint. Science 2014;344:1114-7. DOI PubMed
Lal R. Soil and sanskriti. Available from: https://www.semanticscholar.org/paper/Soil-and-SanskritiLal/e152f6c25061149e116345d1f5f23925226c1785 [Last accessed on 13 Apr 2022].
Lal R. The soil-peace nexus: our common future. Soil Sci. Plant Nutr 2015;61:566-78. DOI
FAO, ITPS. Status of the World’s Soil Resources (SWSR)-main report. Available from:
https://www.fao.org/documents/card/zh/c/c6814873-efc3-41db-b7d3-2081a10ede50/ [Last accessed on 13 Apr 2022].
Bongaarts J. IPBES. Summary for policymakers of the global assessment report on biodiversity and ecosystem services of the
intergovernmental science-policy platform on biodiversity and ecosystem services. Population and Development Review 2019;45:6801. DOI
Lal R. Integrating animal husbandry with crops and trees. Front Sustain Food Syst 2020;4:113. DOI
Weinzettel J, Vačkářů D, Medková H. Potential net primary production footprint of agriculture: a global trade analysis. Journal of
Industrial Ecology 2019;23:1133-42. DOI
Lal R. Digging deeper: a holistic perspective of factors affecting soil organic carbon sequestration in agroecosystems. Glob Chang Biol
2018;24:3285-301. DOI PubMed
Lal R, Smith P, Jungkunst H. F, et al. The carbon sequestration potential of terrestrial ecosystems. Available from:
https://www.jswconline.org/content/73/6/145A.short [Last accessed on 13 Apr 2022].
Xu Z, Sun DW, Zeng XA, Liu D, Pu H. Research developments in methods to reduce the carbon footprint of the food system: a
review. Crit Rev Food Sci Nutr 2015;55:1270-86. DOI PubMed
Leach AM, Emery KA, Gephart J, et al. Environmental impact food labels combining carbon, nitrogen, and water footprints. Food
Policy 2016;61:213-23. DOI
Wu X, Hu S, Mo S. Carbon footprint model for evaluating the global warming impact of food transport refrigeration systems. Journal
of Cleaner Production 2013;54:115-24. DOI
Lal R, Monger C, Nave L, Smith P. The role of soil in regulation of climate. Philos Trans R Soc Lond B Biol Sci 2021;376:20210084.
DOI
Lu C. Q, Yu Z, Tian H.Q, Hennessy D.A, Feng H.L, et al. Increasing carbon footprint of grain crop production in the US Western
Corn Belt. Available from: https://iopscience.iop.org/article/10.1088/1748-9326/aae9fe/meta [Last accessed on 13 Apr 2022].
Millar N. , Doll, J.E., Robertson, G.P., 2014. Management of nitrogen fertilizer to reduce nitrous oxide emissions from field crops
(
E
3
1
5
2
)
.
A
v
a
i
l
a
b
l
e
f
r
o
m
:
https://www.canr.msu.edu/resources/management_of_nitrogen_fertilizer_to_reduce_nitrous_oxide_emissions_from_fi [Last accessed
on 13 Apr 2022].
Page 18 of 19
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
Lal. Carbon Footprints 2022;1:3
https://dx.doi.org/10.20517/cf.2021.05
Vittis Y, Folberth C, Bundle S. -C, Obersteiner M. Restoring nature at lower food production costs. Available from:
https://www.leap.ox.ac. :uk/article/restoring-nature. DOI
Rockström J, Steffen W, Noone K, et al. Planetary boundaries: Exploring the safe operating space for humanity. Available from:
http://www.ecologyandsociety.org/vol14/iss2/art32/ [Last accessed on 13 Apr 2022].
Liu W, Zhang G, Wang X, Lu F, Ouyang Z. Carbon footprint of main crop production in China: magnitude, spatial-temporal pattern
and attribution. Sci Total Environ 2018;645:1296-308. DOI PubMed
Sah D, Devakumar A. The carbon footprint of agricultural crop cultivation in India. Carbon Management 2018;9:213-25. DOI
O’brien M, Schütz H, Bringezu S. The land footprint of the EU bioeconomy: Monitoring tools, gaps and needs. Land Use Policy
2015;47:235-46. DOI
Gan Y, Liang C, Wang X, Mcconkey B. Lowering carbon footprint of durum wheat by diversifying cropping systems. Field Crops
Research 2011;122:199-206. DOI
FAO. Climate smart agiculture source book. Available from: http://www.fao.org/climate-smart-agriculture-sourcebook/en/ [Last
accessed on 13 Apr 2022].
Brankatschk G. , Finkbeiner M. Crop rotations and crop residues are relevant parameters for agricultural carbon footprints. Available
from: https://link.springer.com/article/10.1007/s13593-017-0464-4 [Last accessed on 13 Apr 2022].
Castanheira ÉG, Freire F. Greenhouse gas assessment of soybean production: implications of land use change and different cultivation
systems. Journal of Cleaner Production 2013;54:49-60. DOI
Hu Y, Zheng J, Kong X, Sun J, Li Y. Carbon footprint and economic efficiency of urban agriculture in Beijing-a comparative case
study of conventional and home-delivery agriculture. Journal of Cleaner Production 2019;234:615-25. DOI
Kassam A, Friedrich T, Derpsch R. Global spread of conservation agriculture. International Journal of Environmental Studies
2018;76:29-51. DOI
Lal R, Mohtar R. H, Assi A.T, Ray R, Baybil H, et al. Soil as a basic nexus tool: soils at the center of the food-energy-water nexus.
Available from: https://link.springer.com/article/10.1007/s40518-017-0082-4 [Last accessed on 13 Apr 2022].
Okigbo B. N, Lal R. Role of cover crops in soil and water conservation. Available from: https://agris.fao.org/agrissearch/search.do?recordID=XF8001981 [Last accessed on 13 Apr 2022].
Nair PK, Mohan Kumar B, Nair VD. Agroforestry as a strategy for carbon sequestration. Z Pflanzenernähr Bodenk 2009;172:10-23.
DOI
Rosenstock TS, Wilkes A, Jallo C, et al. Making trees count: measurement and reporting of agroforestry in UNFCCC national
communications of non-Annex I countries. Agric Ecosyst ;284:106569. DOI
Brown RM, Dillon CR, Schieffer J, Shockley JM. The carbon footprint and economic impact of precision agriculture technology on a
corn and soybean farm. J Environ. Econ Polic 2016;5:335-48. DOI
Ratchawat T, Panyatona S, Nopchinwong P, Chidthaisong A, Chiarakorn S. Carbon and water footprint of robusta coffee through its
production chains in Thailand. Available from: https://link.springer.com/article/10.1007/s10668-018-0299-4 [Last accessed on 13 Apr
2022].
van Rikxoort H, Schroth G, Laderach P, Rodriguez-Sanchez B. Carbon footprints and carbon stocks reveal climate-friendly coffee
production. Available from: https://link.springer.com/article/10.1007/s13593-014-0223-8 [Last accessed on 13 Apr 2022].
Martins L. D, Eugenio F.C, Rodrigues W.N, Tomaz M.A, dos Santos A.R, et al. Carbon and water footprints in Brazilian coffee
plantations - the spatial and temporal distribution. Available from: https://novaresearch.unl.pt/en/publications/carbon-and-waterfootprints-in-brazilian-coffee-plantations-the-s [Last accessed on 13 Apr 2022].
Persson U. M, Johansson D.J.A, Cederberg C, Hedenus F, Bryngelsson D. Climate metrics and the carbon footprint of livestock
products: where’s the beef? Available from: https://iopscience.iop.org/article/10.1088/1748-9326/10/3/034005 [Last accessed on 13
Apr 2022].
Patra AK. Accounting methane and nitrous oxide emissions, and carbon footprints of livestock food products in different states of
India. Journal of Cleaner Production 2017;162:678-86. DOI
Ridoutt BG, Page G, Opie K, Huang J, Bellotti W. Carbon, water and land use footprints of beef cattle production systems in southern
Australia. Journal of Cleaner Production 2014;73:24-30. DOI
Cerri CC, Moreira CS, Alves PA, et al. Assessing the carbon footprint of beef cattle in Brazil: a case study with 22 farms in the State
of Mato Grosso. Journal of Cleaner Production 2016;112:2593-600. DOI
Rojas-Downing MM, Nejadhashemi AP, Elahi B, et al. Food footprint as a measure of sustainability for grazing dairy farms. Environ
Manage 2018;62:1073-88. DOI PubMed
Yan MJ, Humphreys J, Holden NM. The carbon footprint of pasture-based milk production: can white clover make a difference? J
Dairy Sci 2013;96:857-65. DOI PubMed
Ridoutt B. Climate neutral livestock production-a radiative forcing-based climate footprint approach. Journal of Cleaner Production
2021;291:125260. DOI
Lal R. Soil carbon sequestration impacts on global climate change and food security. Science 2004;304:1623-7. DOI PubMed
Buratti C, Fantozzi F, Barbanera M, Lascaro E, Chiorri M, Cecchini L. Carbon footprint of conventional and organic beef production
systems: an Italian case study. Sci Total Environ 2017;576:129-37. DOI PubMed
Ibidhi R, Ben Salem H. Water footprint of livestock products and production systems: a review. Anim Prod Sci 2020;60:1369. DOI
Velarde-Guillen J, Arndt C, Gomez C. A. Carbon footprint in Latin American dairy systems. Available from:
Lal. Carbon Footprints 2022;1:3
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
https://dx.doi.org/10.20517/cf.2021.05
Page 19 of 19
https://link.springer.com/article/10.1007/s11250-021-03021-6 [Last accessed on 13 Apr 2022].
Espinoza-Orias N, Stichnothe H, Azapagic A. The carbon footprint of bread. Available from:
https://link.springer.com/article/10.1007/s11367-011-0271-0 [Last accessed on 13 Apr 2022].
Treu H, Nordborg M, Cederberg C, et al. Carbon footprints and land use of conventional and organic diets in Germany. Journal of
Cleaner Production 2017;161:127-42. DOI
Pearson P. Driven to waste: designing a better global food system. Available from: https://www.wwf.or.th/?369116/Driven-to-WasteDesigning-a-Better-Global-Food-System [Last accessed on 13 Apr 2022].
RTS. Food waste in America in 2021: statistics + facts. Available from: https://www.rts.com/wpcontent/uploads/2021/04/RTS_Food_Waste_Guide_2021.pdf [Last accessed on 14 Apr 2022].
RTS. Food Waste in America in 2022: statistics & facts. Available from: https://www.rts.com/resources/guides/food-waste-america/
[Last accessed on 14 Apr 2022].
EPA. United States 2030 food loss and waste reduction goal. Available from: https://www.epa.gov/sustainable-managementfood/united-states-2030-food-loss-and-waste-reduction-goal [Last accessed on 13 Apr 2022].
Reutter B, Lant P, Reynolds C, Lane J. Food waste consequences: environmentally extended input-output as a framework for analysis.
Journal of Cleaner Production 2017;153:506-14. DOI
Tonini D, Albizzati PF, Astrup TF. Environmental impacts of food waste: learnings and challenges from a case study on UK. Waste
Manag 2018;76:744-66. DOI PubMed
Saraiva Schott A, Cánovas A. Current practice, challenges and potential methodological improvements in environmental evaluations of
food waste prevention-a discussion paper. Resour Conserv Recycl 2015;101:132-42. DOI
Song G, Semakula HM, Fullana-i-palmer P. Chinese household food waste and its’ climatic burden driven by urbanization: a bayesian
belief network modelling for reduction possibilities in the context of global efforts. Journal of Cleaner Production 2018;202:916-24.
DOI
Kashyap D, Agarwal T. Food loss in India: water footprint, land footprint and GHG emissions. Available from:
https://link.springer.com/article/10.1007/s10668-019-00325-4 [Last accessed on 13 Apr 2022].
Golan E. The US food waste challenge. Available from: https://www.ncsl.org/documents/statefed/SarahEckhouseUSDA.pdf [Last
accessed on 13 Apr 2022].
Parfitt J, Barthel M, Macnaughton S. Food waste within food supply chains: quantification and potential for change to 2050. Philos
Trans R Soc Lond B Biol Sci 2010;365:3065-81. DOI PubMed PMC
Kibler KM, Reinhart D, Hawkins C, Motlagh AM, Wright J. Food waste and the food-energy-water nexus: a review of food waste
management alternatives. Waste Manag 2018;74:52-62. DOI PubMed
Sarker T, Kibler K, Reinhart D. Concept mapping of food waste management alternatives within the food-energy-water nexus.
Available from: https://ascelibrary.org/doi/abs/10.1061/9780784479865.016 [Last accessed on 13 Apr 2022].
Schanes K, Giljum S, Hertwich E. Low carbon lifestyles: a framework to structure consumption strategies and options to reduce
carbon footprints. Journal of Cleaner Production 2016;139:1033-43. DOI
FAO. Food Wastage Footprint: Full-Cost Accounting. Available from: https://www.fao.org/3/i3991e/i3991e.pdf [Last accessed on 13
Apr 2022].
Friedlingstein P, Jones M. W, O’Sullivan M, et al. Global carbon budget 2021. Available from:
https://essd.copernicus.org/preprints/essd-2021-386/ [Last accessed on 13 Apr 2022].
Ramaswamy V, Boucher O, Haigh J, et al. Radiative forcing of climate change. Available from: https://www.osti.gov/biblio/899821
[Last accessed on 13 Apr 2022].
Worldometer, 2022. CO2 Emissions per Capita. Available from: https://www.worldometers.info/co2-emissions/co2-emissions-percapita/ [Last accessed on 14 Apr 2022].
FAO. FAOSTAT statistical database. Available from: https://www.fao.org/faostat/en/ [Last accessed on 13 Apr 2022].