Did you know that Canada's extensive agricultural industry not only significantly contributes to the country's GDP but also raises critical environmental concerns? While indulging in months of eating in-season vegetables, consumers are increasingly aware of the looming environmental impacts associated with imported food.

Many consumers opt to buy local produce, believing that vegetables cultivated nearby in greenhouses are inherently more sustainable than those transported thousands of kilometres to Canadian markets. However, the concept of shopping sustainably extends beyond mere proximity. Take tomatoes, a ubiquitous staple on our tables. This article delves into the intricate carbon footprint of tomatoes, drawing comparisons between greenhouse production and the long-distance journey from open fields in Mexico.


Canada's agricultural and agri-food system contributes significantly to the nation's economy, representing 7% of its GDP and generating $143.8 billion in revenue in 2022. Notably, with the flourishing expansion of greenhouse vegetable operations, an imperative arises to address the environmental footprint of agricultural practices and their associated supply chains.

In today's era, where sustainability reigns as a paramount concern, understanding the carbon footprint of diverse agricultural practices is not just advisable but imperative. Among the myriad agricultural products, tomatoes stand out as a ubiquitous commodity with profound environmental implications. This study embarks on a comprehensive exploration of the carbon footprints associated with the production of 1 kg of fresh tomatoes, strategically comparing greenhouse production against open-field cultivation. Leveraging CarbonGraph's cutting-edge life cycle assessment (LCA) cloud-based software, we delve deep into the environmental ramifications of each scenario.

Life cycle assessment (LCA), recognized as a standardized methodology for evaluating product inputs, outputs, and environmental impacts throughout their lifecycle, holds immense significance across various sectors, including agriculture and food production. Its widespread application underscores its utility in informing sustainable practices and mitigating environmental footprints.

Study Objectives

This study aims to develop a basic understanding of the primary impact drivers within the agricultural supply chain, with a specific focus on tomato production. Employing a life cycle assessment methodology following ISO 14040 standards, we analyze the carbon footprint of tomato distribution, utilizing a functional unit of 1 kg of fresh tomatoes.

Leveraging CarbonGraph software and the EcoInvent database, we delve into the Climate Change impact category. CarbonGraph, equipped with state-of-the-art technology such as large language models and cloud-enabled automation, offers a user-friendly interface for generating high-quality LCAs.

Furthermore, this study seeks to demonstrate how CarbonGraph empowers LCA practitioners to model scenarios, conduct analyses, and share results efficiently, thereby facilitating informed decision-making towards sustainable practices.

The selection of scenarios for our tomato distribution case study aims to underscore the contrasting dynamics between localized production and long-distance distribution. The dichotomy between greenhouse production and open-field cultivation exemplifies the diverse strategies employed in agricultural practices influenced by climate, geography, and market demand.

Our exploration begins with a simple life cycle assessment (LCA) application, employing the framework delineated by ISO 14040. In collaboration with CarbonGraph, a pioneering software harnessing cutting-edge technology and the expansive EcoInvent database, we delve into the depths of tomato production, aiming to unravel its carbon footprint.

Scenario 1: Greenhouse Production

In the first scenario, we are examining the production of fresh-grade tomatoes in a heated greenhouse. The farm is located within a short distance of 70 kilometres from the distributor, and an additional 10 kilometres from the retail market. This short distance has the potential to reduce the carbon emissions associated with transportation and logistics.

Heated greenhouse production is appealing because it allows us to grow crops like tomatoes all year round, even in places with cold winters like Canada. However, this method of production relies heavily on energy consumption, mostly from natural gas. This energy is used to power furnaces, boilers, and radiant heating systems, but unfortunately, this comes at the expense of carbon emissions.

After analyzing the contributions, we have found that 95% of the emissions come from tomato production in heated greenhouses. Only 4% of the emissions come from the transformation of electricity voltage, while the remaining 1% is due to transportation by freight lorries. All of these factors combined result in a carbon footprint of 1.07 kg CO2-Eq per 1 kg of fresh tomatoes, which we have calculated using CarbonGraph's LCA framework.

Fig.1 Life Cycle Breakdown View of Local Local Tomatoes

Scenario 2: Open-field Cultivation

On one hand, we have tomatoes cultivated in greenhouses and grown in a controlled environment. On the other hand, we have fresh-grade tomatoes grown openly on Mexican farms. Despite the staggering 3,800-kilometer journey these tomatoes make to reach the local distributor in Southern Ontario, they make it to retail shelves after just a 10-kilometer journey.

The the production of 1 kg of fresh tomatoes causes a carbon footprint of 775 g CO2-Eq. The transportation of the tomatoes is the major contributor, accounting for 76% of the climate change impact. The remaining 5% comes from electricity voltage transformation. The production of tomatoes contributes to 19% of the overall impact.

Fig.2 Life Cycle Breakdown View of Imported Tomatoes

Implications for sustainability

Focusing solely on greenhouse gas emissions overlooks a crucial aspect of a vegetable's ecological footprint: water usage, waste management, and more. For instance, it's vital to consider how much water a plant requires to grow and its impact on local water systems. Unlike greenhouse gas emissions, the source of water significantly impacts sustainability. Whether water is abundant or scarce in a region affects its ecological footprint. Understanding these nuances is pivotal for truly assessing the sustainability of agricultural practices.

Beyond the realm of analysis lies the realm of action. CarbonGraph heralds a new era of empowerment, offering LCA practitioners a conduit to model scenarios, perform analyses, and disseminate results effectively. Armed with this arsenal of knowledge, stakeholders are empowered to make informed decisions, steering the agricultural supply chain towards the shores of sustainability.

In conclusion, from the sheltered embrace of heated greenhouses to the sun-drenched expanses of open fields, each scenario bears its own tale of triumphs and tribulations. Yet, amidst this complexity lies a beacon of hope – the power of knowledge to catalyze change. As we chart a course toward a sustainable future, let us heed the lessons gleaned from the humble tomato, for therein lies the seed of transformation.

CarbonGraph served as the cornerstone for quantifying the environmental impact in this example. By leveraging this software, we gained access to a robust framework that not only generated crucial data but also facilitated informed decision-making. Each feature within CarbonGraph is meticulously designed with a clear objective, such as enhancing product sustainability. This targeted approach ensures that users can effectively utilize the software to achieve their sustainability goals, making it an indispensable tool in the journey towards environmental stewardship.


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