Assessment of Organizational Carbon Footprints in a Rubber Plantation Company: A Systematic Approach to Direct and Indirect Emissions

Abstract

This study presents a comprehensive organizational carbon footprint assessment that integrates Scope 1, 2, and 3 emissions for a rubber plantation company, including often-overlooked non-energy sources such as fertilizer application, employee commuting, company-owned vehicle operations, and wastewater discharge. Using the Greenhouse Gas Protocol standard, IPCC 2006 guidelines, and locally adapted emission factors, the assessment quantified the company’s total organizational carbon footprint at 3125 tCO₂e—revealing a previously undocumented emission profile where methane from wastewater discharge, nitrous oxide from fertilizer application, and carbon dioxide from purchased electricity collectively account for over 75% of total emissions. This finding challenges conventional rubber industry practice, which has historically focused on energy-related emissions alone. Three targeted mitigation scenarios were evaluated: (1) optimized nutrient management to reduce fertilizer usage, (2) solar photovoltaic installation to offset grid electricity consumption, and (3) advanced wastewater treatment using Fenton’s reagent combined with activated carbon. Results demonstrate that substantial emission reductions are achievable while maintaining or enhancing productivity and profitability. By establishing a replicable methodological framework grounded in comprehensive emission accounting, this study advances environmental management practices in the rubber sector and provides actionable strategies for plantation-based industries to meet national sustainability agendas and international climate commitments.

1. Introduction

Climate change is a significant issue of the 21st century, which requires immediate and coordinated action from all sectors [1]. Adopted at COP21 in 2015, the Paris Agreement represented a historic worldwide agreement among 197 countries to limit global warming to well below 2 °C, ideally 1.5 °C, relative to preindustrial levels to mitigate the effects of climate change. Achieving this goal is essential for preventing disastrous environmental effects. According to the Intergovernmental Panel on Climate Change [2,3], maintaining warming below 1.5 °C would greatly reduce the probability of extreme weather events, such as flooding. The primary cause of this crisis is the increase in the atmospheric concentration of greenhouse gases (GHG), which worsens the greenhouse effect and causes unpredictable weather patterns [4].

In this context, the idea of a carbon footprint has become essential for measuring human activity-induced greenhouse gas emissions, allowing well-informed environmental decision-making [5]. Consequently, industries are increasingly adopting low-carbon sustainable practices in response to the growing demands of investors, consumers, and regulators [6]. The organizational carbon footprint, which includes both direct and indirect emissions from operations, provides a thorough understanding of an entity’s environmental impact.

Organizations must have a sophisticated understanding of carbon footprint measurement frameworks to effectively mitigate climate change [7]. Carbon footprints can be evaluated at the organizational, product, or individual levels [8]. According to Gandola and Asdrubali [9], individual footprints consider emissions from consumption patterns such as housing, food, clothing, and transportation. Product footprints adopt a cradle-to-grave approach, evaluating emissions at every stage of the product life cycle, from raw materials to production, use, and ultimately disposal [10]. Emissions from fleet operations, facilities, and business travel are all included in organizational footprints [11], providing a more comprehensive view of the influence of institutions [4].

To ensure consistency in carbon footprint printing, standardized methodologies are necessary. The PAS guidelines from the British Standards Institution [12], ISO 14064 [13], and the GHG Protocol of the World Resources Institute and the World Business Council for Sustainable Development are some of the most well-known frameworks [14]. The GHG Protocol remains the most widely used standard and offers detailed guidance for creating organizational GHG inventories [15].

Scope 1 (direct emissions), scope 2 (indirect emissions from purchased electricity, heat, or steam), and scope 3 (all other indirect emissions, including those from supply chains, employee travel, and outsourced activities) are the three categories into which the GHG Protocol divides emissions [16]. Although scope 3 emissions occur externally frequently and require careful data collection to ensure precision and comparability, scope 1 and scope 3 emissions originate within the organizational boundary [17]. Scope 3 emissions often account for the largest portion of the overall emissions, and underestimating them could result in serious errors in footprint calculations [18].

The agricultural sector is a major contributor to anthropogenic greenhouse gas emissions globally, which requires a comprehensive understanding of its environmental impacts [5]. Among agricultural commodities, natural rubber is a strategically important renewable resource with diverse industrial applications, including tires, medical gloves, adhesives, and industrial components [19]. Unlike synthetic alternatives derived from petroleum-based feedstocks, natural rubber is biodegradable and capable of long-term carbon fixation, positioning it as a critical sustainable material in a carbon-constrained world. Global production is concentrated in South and Southeast Asia, with Sri Lanka contributing significantly through plantation-based systems that not only generate foreign exchange but also sustain rural livelihoods. However, the cultivation and processing of natural rubber require substantial inputs of fertilizers, energy, and water, leading to notable environmental impacts. Understanding the carbon footprint of natural rubber plantations is therefore vital for ensuring the long-term sustainability of this renewable resource while maintaining its competitiveness with synthetic rubber. The natural rubber industry in Sri Lanka exemplifies this challenge. As the country’s third-largest foreign exchange earner, it contributed ca. USD 930 million in foreign exchange revenue in 2023 [1,17] and generated ca. 300,000 direct and indirect jobs [17]. However, the sector also contributes to climate change while providing essential economic benefits, highlighting the need for sustainable practices informed by a detailed analysis of the carbon footprint [20].

A comprehensive assessment of greenhouse gas emissions from the natural rubber sector must cover all stages of the life cycle, namely, land preparation, planting, latex extraction, processing, and distribution [20,21]. Land conversion for rubber plantations, especially when it involves deforestation, results in immediate carbon emissions due to the release of stored carbon in biomass and soil [22]. Furthermore, the use of fertilizers, pesticides, and herbicides in rubber cultivation contributes to greenhouse gas emissions, particularly nitrogen oxide from nitrogen-based fertilizers [23]. The energy consumption during latex extraction, processing, and transportation further adds to the carbon footprint, highlighting the need for energy-efficient technologies and practices. Waste generated from rubber processing, including wastewater and solid waste, can also contribute to greenhouse gas emissions if not managed appropriately. Specifically, improper wastewater treatment can generate substantial amounts of methane, a potent greenhouse gas that is highly detrimental to the environment.

Scholars have investigated the carbon footprint of rubber industry through various methodological lenses. For instance, Kumara et al. [24] conducted a case study on the carbon footprint of a rubber/sugarcane intercropping system. Several studies have evaluated environmental sustainability in crepe rubber manufacturing using a life cycle assessment [25,26]. Vidanagama and Lokupitiya [27] examined energy use and greenhouse gas emissions related to the manufacturing processes of tea and rubber. Similar carbon footprint assessments have been conducted across major rubber-producing countries, including Thailand [28], Indonesia [29], and Malaysia [30]. Furthermore, Dayaratne and Gunawardana [31] conducted a study on carbon footprint reduction strategies in rubber production within small and medium-sized enterprises (SMEs) in Sri Lanka.

However, none of these studies have adopted a comprehensive organizational carbon footprint approach that captures Scope 1, 2, and 3 emissions. Specifically, non-energy-related emissions arising from agricultural inputs such as fertilizers, pesticides, herbicides, and fungicides remain underexplored. Fugitive emissions from sources such as fire extinguishers and those related to solid waste disposal and wastewater discharge are consistently overlooked. Additionally, Scope 3 emissions—including employee commuting, business travel, and electricity transmission losses—are often underestimated or entirely excluded. This methodological gap is particularly pronounced in smallholder and SME contexts in rubber-producing regions. Consequently, there remains a substantial knowledge gap in understanding the full organizational carbon footprint of rubber production systems, which hinders the formulation of evidence-based mitigation strategies aligned with climate commitments and market demands.

This study uses the Greenhouse Gas Protocol [32] to assess the organizational carbon footprint in a rubber plantation company based in Sri Lanka. The scope of the assessment includes both direct and indirect GHG emissions. Specifically, it evaluates emissions from on-site energy use (e.g., generators) and fugitive sources (e.g., fire extinguishers), transportation (e.g., company-owned vehicles), solid waste (e.g., rain-guard polythene), and wastewater. Indirect emissions include power consumption from the grid, transmission losses, employee commutes, air travel, and the use of agricultural inputs. Although conventional energy-related emissions such as fuel and electricity consumption were included, particular emphasis was placed on non-energy sources—such as fertilizer application and wastewater discharge—that are often underrepresented in organizational assessments. Performing such a quantification will promote a comprehensive understanding of organizations based on the carbon footprint of the natural rubber industry, enabling the identification of key emission sources, hotspots, and effective interventions.

2. Materials and Methods

2.1. Study Area and Organizational Boundaries

The case study focuses on one of the largest natural rubber exporting companies in Sri Lanka, situated in Ratnapura District, a major rubber-producing region. The company manages ten rubber plantation estates and typically produces 2000 tonnes of rubber crops annually. Operating 350 days a year with eight-hour shifts, the company employs 1921 workers across its operations.

The GHG Protocol was selected for this study due to its widespread adoption as the most recognized international standard for organizational carbon accounting, its applicability across diverse sectors including agriculture, and its provision of clear guidance for defining organizational boundaries and categorizing emission sources [14]. The organizational boundary covers ten rubber plantation estates managed by the company, each representing distinct operational units that contribute to Scope 1, 2, and 3 emissions. The boundary was defined according to the Greenhouse Gas Protocol’s operational control approach, ensuring that all activities under the company’s management are included in the assessment. The emission sources associated with each scope are summarized in Figure 1. According to the GHG Protocol, scope 1 (direct emissions), scope 2 (indirect emissions from purchased electricity, heat, or steam), and scope 3 (all other indirect emissions, including those from supply chains, employee travel, outsourced activities, upstream transportation of raw materials, and end-of-life treatment of products) are the three scope categories used in this study to analyze the system boundary and determine the carbon footprint. Figure 1 shows the associated emission sources for each of these categories. Examples of scope 1 emissions that occur on-site include generators, water pumps, LPG gas consumption, fugitive emissions, mobile combustion emissions, solid waste from the disposal of polythene rain guards, wastewater discharge, and generator emissions. The only source of scope 2 emissions is the electricity purchased by the company. The use of weedicides, pesticides, fungicides, and fertilizers, employees’ commutes, and emissions from non-company vehicles and business flights associated with organizational activities are related to scope 3 emissions. These categories were selected based on materiality and data availability. The use of weedicides, pesticides, fungicides, and fertilizers, employees’ commutes, and emissions from non-company vehicles and business flights associated with organizational activities are related to scope 3 emissions. Scope 3 categories were selected based on materiality and data availability. Included categories—employee commuting, purchased agricultural inputs (fertilizers, pesticides, fungicides, weedicides), hired transportation, business travel, waste disposal, and electricity transmission losses—represent significant emission sources with accessible data from company records and employee surveys. Excluded categories include capital goods (buildings and machinery—difficult to obtain manufacturing emission data and minor annual impact when amortized over asset lifetime), and downstream activities beyond the plantation gate (company sells raw latex without involvement in further transport or processing).

2.2. Data Collection

All major emission sources were identified to develop the organization’s greenhouse gas emission inventory. Then, the company departments provided activity data for 2023, as detailed in

Table 1. Data on the activities of a rubber plantation company in 2023.

Emission Type	Activity	Data	Unit	Source
Scope 1	Diesel consumption—standby generators	13,804	L	Running chart
	Petrol consumption—standby generators	645	L	Running chart
	LPG consumption	10	tonnes	Running chart
	Petrol consumption—machinery and equipment	4983	L	Running chart
	Fugitive emissions—fire extinguishers	120	kg	Running chart
	Diesel consumption—factory owned vehicles	118,621	L	Running chart
	Petrol consumption—factory owned motorcycles	7093	L	Running chart
	Wastewater discharge	75,479,359	L	Running chart
Scope 2	Purchased grid electricity	1,063,145	kWh	Electricity bills
Scope 3	Consumption of weedicide	4527	kg	Running chart
	Consumption of fungicide	1446	kg	Running chart
	Consumption of fertilizer	468,107	kg	Running chart
	Petrol consumption—personal vehicles (employee commuting)	26,905	L	Questionnaire
	Diesel and petrol consumption—public transport (employee commuting)	218,405	km	Questionnaire
	Diesel and petrol consumption—Hired vehicles (employee commuting)	42,736	L	Invoices
	Air travel	2	Number of travels	Invoices
	Waste transportation	967	km	Questionnaire
	Solid waste generation	43	tonnes	Invoices
	Chemical use	141,117	kg	Running chart

. Scope 1 data were obtained from the company’s fuel consumption and purchase records, including business travel and plantation estate transportation. LPG consumption data were also collected to calculate scope 1 emissions. Transportation emissions were calculated using the total distance driven, fuel type, and vehicle technical specifications found in the company’s documentation. The company’s records also contained fuel consumption data for diesel generators, water pumps, and plantation equipment, such as chainsaws and grass cutters.

Grid-purchased electricity is included in activity data related to GHG emissions that fall into the scope 2 emission category. Energy consumption includes the use of lighting, automated building systems, and operational electricity. The monthly reading of electricity consumption provides activity data for purchasing electricity. The national grid average emission factor that best describes the relevant grid was used to calculate GHG-related electricity.

Scope 3 emissions included employee travel, hired vehicles, fertilizer use, weedicide consumption, fungicide consumption, and waste generation. Travel data in 2023 were determined from employee interviews. To evaluate fuel consumption, the total distance traveled, modes of transport, and type of vehicle employees travel to and from work were used. Data on the amount of fertilizer, weedicide, and fungicide used and greenhouse gas emissions were collected from the company’s records. The type of waste and the amount produced were obtained from the company’s own paperwork and records. The activity data for rental cars and air travel were computed based on the distance traveled in 2023. For this purpose, we used company-owned documents from business trips. The amount of wastewater discharge used to calculate GHG emissions is obtained from monthly wastewater discharge readings. The emissions related to wastewater discharge were calculated based on the IPCC guidelines [33,34] for methane emissions from wastewater discharge using Equation (1).

EF_j = B_o × MCF_j

(1)

where EF_j is the emission factor for each treatment/discharge pathway or system, kg CH₄/kg COD, j is each treatment/discharge pathway or system, B_o is the maximum CH₄ producing capacity, kg CH_4/kg COD and MCF_j is a methane correction factor (fraction).

2.3. Carbon Footprint Methodology

The company’s carbon footprint followed the Greenhouse Gas Protocol, Greenhouse gases—Part 1: Specification with guidance at the organization level to quantify and report greenhouse gas emissions and removals [35]. This document describes the guidelines and specifications for constructing, developing, managing, and reporting GHG emission inventories at the organizational level. Greenhouse gas emissions from the company’s activities were determined by the emission factors related to each activity data. The carbon footprint approach used in this study is based on activity data multiplied by appropriate emission factors that calculate CO₂e emissions or removals per unit of activity using the following Equations (2) and (3):

ACF = AD × EF

(2)

TCF = ACF₁ + ACF₂ + … + ACF_n

(3)

where ACF is the carbon footprint caused by each activity, AD is the activity data in tons (t), and EF is a standard emission factor. Emission rate per unit of activity (CO₂e/tonne), and TCF is the total carbon footprint of the organization expressed in tonnes of equivalent carbon dioxide (tCO₂e).

The emission factors published by the DEFRA [33] were primarily used to quantify greenhouse gas emissions from each activity within the defined organizational boundary. These factors express the relationship between the quantity of pollutants released and the corresponding activity data (e.g., liters of fuel consumed or kilograms of material processed). DEFRA provides annually updated spreadsheets containing conversion values, detailed usage instructions, and methodological documentation describing data compilation and revisions [33]. For electricity-related emissions, national grid emission factors were derived from the Ceylon Electricity Board Statistical Digest 2021 and the Sri Lanka Energy Balance Report 2021 [36,37]. Sri Lankan national grid comprised ca. 35% hydropower, 47% thermal power (coal and oil), and 18% renewable energy sources (solar, wind, biomass) [36]. Based on the Sri Lanka Energy Balance Report 2021 [37], a baseline emission factor of 0.4278 kg CO₂e per kWh was applied to calculate Scope 2 emissions from purchased electricity. In addition, India-specific road transport emission factors [38] were applied for employee commuting calculations to better represent regional vehicle and fuel characteristics. For more details on emission factors please see Tables S2–S4.

2.4. Carbon Fixation Methodology

The amount of carbon fixed per tree (C_tree) was quantified based on an allometric model (Equation (4)) developed based on growth indicators such as tree diameter at 150 cm height (D) and total tree height (H) [39].

C_tree = −5.1 + 144.9 × D² × H

(4)

The diameter of 150 cm height of the tree was taken from 0.1 hectares of randomly selected plot of each rubber field. Due to the practical difficulty in measuring total tree height, it was calculated based on the growth models available with respect to the age of the plantations (Y) as follows in Equation (5):

H = −15.13 + 40.28/(1 + exp (−0.13 (Y − 1.03)))

(5)

The actual tree density of the relevant rubber fields was considered in calculating fixed carbon in the rubber fields. Rubber fields below two years of age were not considered in carbon stocktaking as a general procedure.

2.5. Proposal of Improvement Options

Pareto analysis was applied to systematically identify the most influential emission sources within the organization’s total carbon footprint. This method ranks all emission categories in descending order of their contributions to total greenhouse gas emissions and then calculates the cumulative percentage of each category, defined as the running total of ranked contributions expressed as a percentage of overall emissions. The approach follows the “80/20 rule,” which assumes that approximately 80% of total impacts are caused by roughly 20% of the sources [40]. By constructing a Pareto chart and computing cumulative shares, the analysis enables the identification of the few dominant sources that account for the majority of emissions.

The improvement options were identified through a review of literature and case studies on emission-reduction practices in the agricultural and plantation sectors. Options that were technically feasible and relevant to the operational context of the company were selected for further evaluation.

3. Results and Discussion

3.1. Organizational Carbon Footprint of Rubber Plantation Organization

The organizational carbon footprint recorded 3125.00 tCO₂e in 2023. The distribution of greenhouse gas emissions across scopes 1, 2, and 3, as outlined by the Greenhouse Gas Protocol [32], is illustrated in Figure 2. The diagram simplifies a complex emission inventory by clearly displaying relationships among emission scopes, emission types, sources, and related carbon dioxide equivalents. Scope 1 emissions represent the largest share (ca. 48%), primarily due to methane (CH₄) emissions from wastewater treatment. Scope 3 emissions constitute the second-largest portion (ca. 38%), with significant contributions from the use of chemicals, fertilizers, and rental vehicles, highlighting the environmental impact of agricultural practices and outsourced activities. The majority of scope 2 emissions (ca. 14%) arise from electricity consumption, notably within rubber factories.

3.1.1. Scope 1 Emissions

Figure 3 illustrates that the organization reported 1486.86 tCO₂e of scope 1 emissions for 2023. Wastewater treatment processes accounted for an estimated 38.46 tonnes of methane (CH₄), equivalent to 1076.95 tCO₂e. This methane alone represented approximately 72% of the organization’s scope 1 emissions. Operational vehicles and equipment powered by petrol and diesel also significantly contributed to scope 1 emissions. The vehicle fleet was the largest single source in this category, accounting for 331.23 tCO₂e. Specifically, tractors emitted 149.02 tCO₂e and taxis emitted 74.41 tCO₂e. Standby generators consumed 14,449 L of fuel (see

Table 2. Scope 1 emission sources and their consumption on the rubber plantation estate.

Emission Source	Amount of Consumption	Unit
On site energy
Stand by generator—diesel	13,804.00	L
Stand by generator—petrol	645.00	L
Water pump—diesel	35.00	L
LPG gases	9.74	tonnes
Grass cutter—petrol	2574	L
Chain saw—petrol	2022.75	L
Mix blower—petrol	4.00	L
Power sprayer—petrol	10.00	L
Staff/tappel—petrol	137.50	L
Mist blower—petrol	28.00	L
Weeding machines—petrol	155.50	L
Water pump—petrol	16.00	L
Fugitive emissions
Fire extinguishers	120.00	kg
Company owned vehicles
Ambulance—diesel	2751.40	L
Lorry—diesel	26,112.00	L
Cab—diesel	28,291.57	L
Tractor—diesel	56,037.00	L
Motor bike—petrol	7092.82	L
Jeep—diesel	1286.00	L
Van—diesel	3400.40	L
Bachoe—diesel	743.00	L
Wastewater treatment
CH4	38,462.61	kg

), producing 38.21 tCO₂e. Additionally, petrol-powered equipment—including blowers, chainsaws, grass cutters, sprayers, and water pumps—generated 11.60 tCO₂e. Fugitive emissions from fire extinguishers added another 0.12 tCO₂e. Liquefied petroleum gas (LPG) consumption was also notable, totaling 9.74 tonnes (see Table 2) and generating 28.62 tCO₂e.

3.1.2. Scope 2 Emissions

The total electricity consumed during the assessment period was 1,063,145 kWh (see

Table 3. Scope 2 emissions from purchased electricity consumption across various facilities in the rubber plantation organization.

Emission Source	Amount of Consumption	Unit
Purchased electricity
Bungalows	47,050	kWh
Staff quarters	66,489	kWh
Offices	21,179	kWh
Religions places	495	kWh
Factories—rubber	919,243	kWh
Creches	719	kWh
Conference hall	2389	kWh
Tea center	1059	kWh
Dispensary	512	kWh
Other	2319	kWh
Welfare room	223	kWh
Regional stores	1063	kWh
Minor building	404	kWh

), distributed among various operational units. The highest share of consumption was at 919,243 kWh (see Table 3), resulting in 393.25 tCO2e (see Figure 4), which is ca. 86.5% of the total scope 2 emissions (dedicated for rubber factories). Other significant contributors include staff quarters, bungalows, and offices.

3.1.3. Scope 3 Emissions

Table 4. Scope 3 emissions from rubber plantations.

Emission Source	Amount of Consumption	Unit	Emissions of Carbon Dioxide tCO2e
Electricity—transmission & distribution losses
Bungalows	4539.91	kWh	1.94
Staff quartos	6415.61	kWh	2.75
Offices	2043.64	kWh	0.87
Religions places	47.76	kWh	0.02
Factories—rubber	88,698.89	kWh	37.95
Creches	69.38	kWh	0.03
Conference hall	230.52	kWh	0.10
Tea center shop	102.23	kWh	0.04
Dispensary	49.40	kWh	0.02
Other	223.76	kWh	0.10
Welfare room	21.52	kWh	0.01
Regional stores	102.57	kWh	0.04
Minor building	38.98	kWh	0.02
Electricity—transmission & distribution losses	102,584.17	kWh	43.89
Weedicide use	4526.70	kg	44.32
Fungicide use	1446.00	kg	15.31
Fertilizer use	468,106.50	kg	780.41
Staff own vehicle transport
Motor cycle petrol	24,952.30	L	58.51
Three wheel—petrol	1953.00	L	4.58
Public transport
Bus-diesel	213,287.20	km	3.23
Three-wheeler-petrol	5118.00	km	0.58
Hired vehicles
Bowser-diesel	33,211.00	L	88.32
Backho machines—diesel	1985.00	L	5.28
Drone machines—diesel	20.00	L	0.05
Tractor—diesel	1278.00	L	3.40
Lorry—diesel	6207.50	L	16.51
Three wheel—petrol	34.00	L	0.08
Air travel	2.00	travel	0.88
Waste transportation	966.70	km	0.57
Solid waste generation by waste recycled (rain guard polytene) waste	42.59	tonnes	0.91
Chemical use	141,117.12	kg	116.14

summarizes the inventory and carbon footprint related to scope 3 emissions. As per Table 4, scope 3 emissions from the organization totaled 1182.98 tCO₂e during the reporting period. A significant portion of emissions come from agricultural inputs, particularly synthetic fertilizers, fungicides, and weedicides. This use contributed a total of 839.05 tCO₂e. The application alone represented 780.41 tCO₂e, which emphasizes its dominant role in this category.

Hired transportation assets, such as tractors, bowsers, lorries, and construction machinery, contributed 113.64 tCO₂e. Although their fuel consumption was modest compared to industrial activities, their high-intensity and continuous operation notably increased the organization’s scope 3 emissions.

The operations of the organization generate diverse waste streams, including solid waste from rain guard polythene and chemical residues, which collectively contributed 117.62 tCO₂e. A total of 42.59 tonnes of waste were processed through third-party recycling and disposal services. Transportation of waste to these facilities added an additional 0.57 tCO₂e to the emissions inventory. Meanwhile, the use of 141,117 kg of industrial chemicals in various operational activities contributed 116.14 tCO₂e to the emissions inventory.

Electricity transmission and distribution losses contributed 43.89 tCO₂e to Scope 3 emissions. These losses occur between electricity generation and final consumption points, and were calculated by applying nationally recognized grid loss factors to the organization’s electricity consumption data. Among facilities, the rubber factory accounted for the largest share at 37.95 tCO₂e, followed by staff quarters and office buildings.

Employee commuting emissions, including private vehicles and public transport, totaled 66.91 tCO₂e. As shown in Table 4, petrol motorcycles were the dominant source, accounting for 58.51 tCO₂e. Petrol three-wheelers were the second largest contributor at 4.58 tCO₂e.

Air travel emissions were modest at 0.88 tCO₂e, generated from two recorded business trips during the reporting period.

3.2. Carbon Fixation

The plantation contributes to maintaining 137,273 tonnes of carbon stock within the defined boundary. Accordingly, the plantation is responsible for fixing 503,790 tons of atmospheric CO₂ as a mitigation contribution. Table S1 provides additional information on the estate-wise contribution to fixing and maintaining carbon stocks.

3.3. Proposal of Improvement Options

Based on the final carbon footprint calculations and the subsequent Pareto analysis presented in

Table 5. Summary of the Pareto analysis for emission types.

Emission Type/Source	Emissions of Carbon Dioxide tCO2e	% of Total	Cumulative Percentage [%]
CH4	1077	34.5	34.5
Fertilizer	780	25.0	59.4
Purchased electricity	455	14.6	74.0
Owned vehicles transport	331	10.6	84.6
Chemical use	116	3.7	88.3
Hired vehicles	114	3.6	92.0
On site energy	78	2.5	94.5
Employee commuting	67	2.1	96.6
Weedicide	44	1.4	98.0
Electricity transmission & distribution losses	44	1.4	99.4
Fungicide	15	0.5	99.9
Waste	1	0.0	99.9
Air Travel	1	0.0	100.0
Total	3125	100	100.0

, methane emissions from wastewater discharge, fertilizer application, and electricity consumption emerged as the main contributors to the plantation’s overall greenhouse gas emissions. In light of this analysis, and based on evidence from relevant literature and case studies, targeted mitigation strategies focusing on reducing fertilizer application and minimizing wastewater generation primarily through the optimization of wastewater treatment processes and energy use were identified as critical areas for emission reduction and sustainability enhancement.

3.3.1. Option 1: Reduction in Fertilization

Optimizing the timing and frequency of fertilizer applications, in conjunction with waste reduction, improves nitrogen use efficiency in agricultural contexts [41]. Slow-release fertilizers offer a potentially advantageous approach to nutrient management in rubber plantations. However, the environmental consequences, specifically the release of microplastics from polymer coatings, warrant thorough investigation. Environmentally sound alternatives, such as slow-release technologies employing biodegradable or natural coatings, are becoming increasingly viable. More empirical research is needed to comprehensively assess the nutrient release kinetics and environmental effects of these alternatives. In several countries, the adoption of enhanced fertilization strategies can decrease overall fertilizer requirements by ca. 20% [42].

3.3.2. Option 2: Installation of Solar Panels and Implementation of Energy Efficiency Practices

Electricity consumption represents a significant source of greenhouse gas (GHG) emissions within rubber plantation operations, accounting for ca. 16% of total emissions. Therefore, enhancing energy efficiency across processing activities is a critical emission mitigation strategy. The installation of inverters, which regulate the flow of electrical current by gradually increasing the power until the machinery reaches its target operating speed, is a practical intervention. This approach reduces the high energy losses associated with start-up surges and can reduce electricity consumption by approximately 10–12% [41,43]. The adoption of broader energy-efficient measures has demonstrated substantial benefits beyond inverter technology.

For instance, the use of photovoltaic solar panels has significantly reduced electricity demand. According to Dunuwila, Rodrigo, and Goto [26], such interventions can result in a 100% reduction in electricity consumption per metric ton of dry rubber produced. Furthermore, replacing 100% of electricity consumption with solar energy can offset all electricity demand, thereby achieving complete energy savings from conventional power sources. These improvements not only decrease operational energy use but also contribute to the long-term sustainability of natural rubber processing in Sri Lanka.

While solar photovoltaic installation can eliminate ca. 450 tCO₂e from Scope 2 emissions and transmission losses, it is essential to consider the embodied emissions from module manufacturing. The production of solar panels involves energy-intensive processes and raw material extraction, which contribute to upfront carbon emissions. Life cycle assessment studies show that in high-irradiance tropical regions such as Sri Lanka, these manufacturing emissions are offset in ca. 10 years of operation [42]. Beyond this payback period, solar systems continue to generate electricity with significantly lower emissions than fossil fuel-based grid power for the remainder of their 20-year lifespan. Thus, the net emission savings over the system lifetime far exceed the initial manufacturing emissions, demonstrating that solar energy remains a robust mitigation option for rubber plantation operations.

3.3.3. Option 3: Use of Fenton Reagent and Activated Carbon for Wastewater Treatment

An effective strategy to reduce methane emissions from wastewater treatment in the rubber industry involves advanced chemical treatment methods aimed at significantly lowering the chemical oxygen demand (COD) content. One such approach is to combine the Fenton reagent and activated carbon adsorption. This method achieved up to 95% COD removal from rubber processing effluent under optimal conditions, specifically a Fenton reagent molar ratio of 1:250 and a reaction time of 45 min, followed by passage through an activated carbon column [44]. The treated wastewater achieved a final COD concentration of 71 mg/L, TSS of 70 mg/L, and a neutral pH of 7.8, which meet the industrial discharge standards of the Sri Lankan Central Environmental Authority (CEA) [45]. Applying the IPCC [34] methane emission factor (0.2 kg CH₄/kg COD), this 95% reduction in COD translates into a comparable 95% reduction in the potential for methane generation, thus significantly mitigating the industry’s wastewater treatment-related carbon footprint.

3.4. Evaluation of Potential Improvements

3.4.1. Option 1: Reduction in Fertilization

Optimizing fertilizer application represents a key mitigation strategy in reducing greenhouse gas emissions associated with agricultural operations. In the context of this study, it is projected that the implementation of better nutrient management practices will reduce fertilizer use by 20%, resulting in an estimated reduction of 156 tCO₂e from 780 tCO₂e to 624 tCO₂e.

3.4.2. Option 2: Installation of Solar Panels and Implementation of Energy Efficiency Practices

The implementation of energy efficiency measures combined with solar panel installations has the potential to significantly reduce electricity consumption in rubber processing operations. Based on the projected efficiency improvements, electricity consumption can be reduced by approximately 100%, decreasing from 1,063,145 kWh to zero, representing a savings of 1,063,145 kWh. Furthermore, this reduction in energy use leads to a corresponding decrease in electricity transmission and distribution (T&D) losses. From an original T&D loss of 102,584 kWh, an estimated zero can be avoided by reducing the demand at the source.

Consequently, associated greenhouse gas emissions are expected to decline significantly. Emissions from electricity consumption can be reduced from 455 tCO₂e to 100.1 tCO₂e, while emissions from transmission and distribution losses can be reduced from 44 tCO₂e to approximately 9.68 tCO₂e.

Furthermore, in a scenario where 100% of the electricity demand is met through photovoltaic solar panel installations, the organization can achieve complete avoidance of grid-based electricity consumption. This would eliminate all associated emissions from both electricity use and T&D losses, potentially reducing total emissions from 499 tCO₂e to zero. Such a transition would mark a significant milestone in achieving carbon neutrality and enhancing long-term environmental sustainability.

3.4.3. Option 3: Use of Fenton Reagent and Activated Carbon for Wastewater Treatment

Wastewater discharge has been identified as the single source of greenhouse gas emissions, contributing approximately 34.5% of the total emissions, primarily through the release of methane. A promising mitigation strategy involves the application of Fenton reagent coupled with activated carbon adsorption for wastewater treatment. In this context, implementing the treatment process would reduce CH₄-related emissions from an estimated 1077 tCO₂e to 54 tCO₂e, resulting in a net emission reduction of 1023 tCO₂e. This represents a substantial and measurable improvement in the environmental performance of the organization’s wastewater management system.

3.4.4. Combined Scenario: Application of Options 1, 2, and 3

The integrated implementation reduces total emissions from 3125 to 1491 tCO₂e, representing a remarkable ca. 48% reduction in overall greenhouse gas emissions. These collective improvements not only contribute to a reduction in emissions, but also drive substantial reductions in input material costs, energy expenses, and waste management expenditures, improving the operation’s environmental and economic efficiency of the operation.

3.5. Comparative Analysis of Carbon Footprint with Other Studies

Comparing the carbon footprint of rubber plantations with other studies presents inherent challenges due to spatial and temporal variations in emissions [46]. Additionally, discrepancies arise from differences in the boundaries such as whether energy use, input production, land use change and post-harvest stages are considered [47]. These variabilities were taken into account when comparing the findings of this study with the existing literature. Given the scarcity of direct studies on carbon footprint rubber plantations in Sri Lanka, additional comparisons were made with related agricultural systems such as tea, sugarcane, rice, etc.

A study on rubber-sugarcane intercropping systems in Sri Lanka reported a cumulative carbon footprint of 9.71 tCO₂e over a four-year period, corresponding to an average annual emission of 2.43 tCO₂e per hectare [24]. This value exceeds the carbon footprint estimated in this study. The elevated levels of emission observed in their study are likely attributed to the integration of sugarcane cultivation, which is known for the application of intensive nitrogen fertilizers and soil disturbance practices that contribute to increased nitrous oxide (N₂O) emissions.

Despite the prominence of rubber as a perennial crop in Sri Lanka, comprehensive carbon footprint assessments of rubber plantations remain scarce in the national literature, particularly in contrast with assessments conducted for other major agricultural crops. In the current study, the carbon footprint associated with a rubber monoculture plantation was estimated at 0.848 tCO₂e ha⁻¹ yr⁻¹, a value significantly lower than those reported for other crops grown under similar agro-climatic conditions. For example, Rathnayake et al. [48] conducted an extensive inventory of greenhouse gas emissions in the Mahaweli H agricultural zone and documented substantial variability in net CO₂e emissions per hectare per year. Their comparative analysis, presented in Figure 5, illustrates the intensities associated with key crops such as rice [48], maize, soybeans [48], vegetables [48] and Sweet potato [48], manic [48], ground nut [48], sugar cane [48], and Rubber (this study), further underscoring the relatively lower carbon intensity of rubber monoculture systems, as evidenced by the present findings.

Synthetic rubber produced from petroleum-derived monomers, such as butadiene and styrene, is non-renewable and carries a high environmental burden. Recent studies indicate that the production of synthetic rubber emits between 4.9 and 6.0 tCO₂e per tonne of product [49]. In contrast, the present study estimated the carbon footprint of natural rubber cultivation and processing at 1.6 tCO₂e per tonne of product, which is substantially lower than that of synthetic rubber. This comparison underscores the strategic advantage of natural rubber as a renewable material resource with significantly reduced life-cycle greenhouse gas emissions.

Overall, a robust monitoring and evaluation system is essential to ensure progress and adaptability of the improvement strategies. Establishing key performance indicators for emissions, energy use, and transportation efficiency allows for ongoing evaluation and refinement of strategies. Data-driven decision making, guided by real-time performance metrics, ensures that the organization is on track to meet its sustainability goals.

Employee participation plays a crucial role in fostering an organizational culture of sustainability. Implementing green human resource management practices such as incorporating environmental goals into performance evaluations, training programs on energy and waste reduction, and incentives for eco-friendly behavior can drive behavioral change throughout the organization [46,47,50,51,52,53].

Finally, the promotion of external collaboration and transparency can amplify the impact of these strategies. By partnering with government agencies, academic institutions, and NGOs, rubber plantation companies can access technical expertise and innovation [4,51]. Publishing sustainability reports using frameworks such as the Global Reporting Initiative or the Task Force on Climate-related Financial Disclosures enhances stakeholder trust and ensures accountability [54].

Together, these strategies offer a practical and research-informed roadmap to achieve substantial carbon footprint reductions in rubber plantation operations while supporting broader environmental and social goals. Despite the prominence of rubber as a perennial crop in Sri Lanka, comprehensive carbon footprint assessments of rubber plantations remain scarce in the national literature, particularly in contrast with assessments.

3.6. Limitations

While these mitigation scenarios demonstrate substantial emission reduction potentials, their practical implementation requires comprehensive feasibility assessment beyond the scope of this study. Future research should evaluate the economic viability of each option, including capital investment requirements, operational costs, and financial payback periods. Additionally, operational challenges such as technical capacity, infrastructure requirements, and institutional barriers should be systematically assessed. Such techno-economic analysis would provide stakeholders with the necessary information for evidence-based decision-making and prioritization of mitigation investments.

Furthermore, this assessment is subject to uncertainties inherent in activity data collection and emission factor application. Activity data obtained from surveys and company records may be subject to reporting variability and measurement uncertainty. Emission factors adapted from IPCC guidelines and other published sources may not fully capture site-specific conditions, such as local climate, soil characteristics, and operational practices. Despite these limitations, the assessment provides sufficient accuracy for identifying major emission sources and guiding mitigation decisions.

4. Conclusions

Addressing the complex greenhouse gas emission profile of the rubber plantation sector is crucial to achieving national sustainability plans and global climate commitments. This research reveals a previously undocumented emission profile where methane emissions from wastewater treatment, nitrous oxide emissions from fertilizer application, and carbon dioxide emissions from electricity consumption and internal transportation are the dominant contributors under Scope 1, 2, and 3 boundaries—a finding that challenges conventional assumptions about rubber production emissions and highlights the critical importance of comprehensive organizational accounting. This is not merely an accounting exercise, but a strategic necessity to align agro-industrial operations with national sustainability agendas and international climate commitments.

This study quantified the total organizational carbon footprint of the rubber plantation company at 3125 tCO₂e, with methane emissions from wastewater treatment (1077 tCO₂e, 34.5%), fertilizer application (780 tCO₂e, 25.0%), and purchased electricity (455 tCO₂e, 14.6%) collectively accounting for ca. 74% of total emissions. The integrated implementation of three targeted mitigation strategies—optimized fertilizer management, solar photovoltaic installation, and advanced wastewater treatment—demonstrated potential to reduce total emissions to 1491 tCO₂e, representing a 52% reduction while maintaining operational efficiency and economic viability.

Through comprehensive carbon footprint measurement that integrates often-overlooked emission sources, the company gains an essential evidence base to comprehend its environmental impact, monitor trends over time, and prioritize mitigation options. Regular reporting and year-to-year comparison of emissions data improve organizational transparency, improve internal environmental management, and enable alignment with international reporting frameworks such as the Global Reporting Initiative and the Task Force on Climate-related Financial Disclosures. Additionally, such analyses enable proper benchmarking and encourage a data-driven culture necessary for informed decision making and strategic investment in low-carbon technologies.

Significantly, the adoption of integrated mitigation practices—from improved anaerobic digestion through covered lagoon digesters for methane recovery, precision ag via GPS-guided fertilizer application and nitrification inhibitors in fertilizer management, to incorporating renewable energy and smart transportation systems—demonstrates that emission reductions need not come at the expense of productivity or profitability. On the other hand, these interventions also yield co-benefits in the form of resource efficiency gains, cost reductions, and greater operational resilience. Furthermore, the incorporation of green human resource management practices, through training, recruitment, and performance systems, ensures that sustainability becomes embedded in organizational culture and workforce skills.

The inclusion of scope 3 emissions reflects a mature understanding of supply chain dynamics and stakeholder interdependencies. Joint carbon reduction efforts with suppliers, educating customers on product carbon footprint, and engaging the surrounding communities in reforestation efforts not only reduce upstream and downstream emissions but also strengthen the license to operate for the company in an expanding environmentally conscious world market. Integrating green infrastructure and regenerative land-use practices as well synergizes carbon sequestration potential while promoting biodiversity conservation, soil fertility, and climate resilience.

This study contributes a replicable methodological framework that other rubber sector companies can adopt, fundamentally shifting industry practice toward comprehensive carbon accounting. By implementing a strategic, multiscale carbon footprint reduction intervention grounded in empirical evidence and technological innovation, the rubber plantation company positions itself at the forefront of climate action within the agro-industrial sector. The interventions signify a paradigm shift from reactive compliance toward proactive environmental stewardship, climate-resilient business models, and genuine sustainable development. Through the adoption of rigorous carbon accounting and integration of sustainability into core business operations, the company not only gains environmental legitimacy but also creates lasting competitive and financial value in an increasingly carbon-constrained global economy. This framework demonstrates that rubber producers can simultaneously meet climate obligations, enhance operational efficiency, and strengthen market positioning—offering a scalable model for sectoral transformation toward sustainability.