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Page 2 of 20 Lal. Carbon Footprints 2026, 5, 10

payments for ecosystem services and the establishment of the Soil Health Act. Reducing EFP of agro-ecosystems is
narrated in relation to Sustainable Development Goals of the United Nations.

INTRODUCTION
Food systems, from production to consumption and disposal of by-products and waste, contribute as much
as 30% of gaseous emissions which aggravate anthropogenic climate change (ACC). It is estimated that in
2022, gaseous emissions from agri-food systems were 16.2 Pg of CO equivalents (CO eq; Pg = petagram =
2
2
10 g = 1 giga ton or Gt = 1 billion metric ton) . Of this, crop and livestock activities contributed 7.8 Pg of
[1]
15
CO eq, land use change 3.1 Pg CO eq, and pre- to post-production about 5.3 Pg CO eq. Furthermore, the
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2
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agri-food emission intensity was 2.6 kg CO per US dollar . Therefore, reducing the carbon footprint (CFP)
[1]
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of agro-ecosystems is a high priority. However, CFP is one of the components of ecological footprint (EFP),
which refers to total of all resources used in agroecosystems including production, consumption and waste
disposal. In this context, the term sustainability refers to a scenario in which a community or region lives
within its natural resources. Thus, a judicious management of natural resources can lead either to ecological
surplus when biocapacity exceeds the EFP or ecological deficit when EFP exceeds the biocapacity. In other
terms, an ecological deficit implies unsustainable management of natural resources, leading to soil and
environmental degradation and attendant consequences of hunger, malnutrition, civil strife, political unrest,
or war, and of course, an increase in risks of ACC. Therefore, creating ecological surplus by judicious land
use and adoption of best management practices (BMPs) is critical to advancing Sustainable Development
Goals (SDGs) or the Agenda 2030 of the United Nations, and also advancing global peace and tranquility.

There are three components of CFP of agro-ecosystems: direct or on-farm emissions, indirect or off-farm
operations, and other sources [Figure 1].

Agroecosystems that contribute to ACC by emission of greenhouse gases (GHGs) are deforestation or land
use conversion from natural to agroecosystems and agricultural operations (i.e., plowing, fertilizer
application, pesticide use, supplemental irrigation, grain drying, food processing, and food transport).
Agro-ecosystems also contribute to the emission of GHGs through soil degradation by numerous
degradative processes such as accelerated erosion, waterlogging or anaerobiosis, drastic soil disturbance (i.e.,
by war and mining), urbanization, farm operations, sediment transport to aquatic ecosystems, and external
inputs. Thus, the objective of this article is to discuss ten issues as follows: (1) conceptual basis of reducing
net EFP), (2)dynamics of soil C pool and global warming, (3) soil management practices which sequester C,
(4) processes of C sequestration in soil so that agro-ecosystems can be emission negative, (5) co-benefits and
tradeoffs of soil C sequestration, (6) national and global potential of soil C sequestration, (7) ecological limits
of soil C sequestration (8) implementation of national and international initiatives, (9) policy options to
promote soil/terrestrial C sequestration by judicious land use and adoption/upscaling of BMPs, and (10)
research priorities. Discussions on these objectives are discussed below in the sequence in which the
objectives are listed.

CONCEPTUAL BASIS OF REDUCING ECOSYSTEM AND CARBON FOOTPRINT OF

AGRO-ECOSYSTEMS
The CFP of agro-ecosystems refers to total GHG emissions (CO , CH , N O) from all farm operations
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2
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including on-farm and off-farm activities and those from soil degradation and manure management. Under
the overall umbrella of EFP, the CFP must be credibly assessed. There is a need to enhance clarity and
transparency of EFP and CFP to understand the impact of human demand for ecosystem services (ESs) on