A carbon footprint represents the total greenhouse gases, primarily carbon dioxide, released into the atmosphere by an activity or product. Every aspect of our food, from its cultivation to its presence on our plates, contributes to this footprint. This includes processes like farming, transportation, processing, and even waste. Understanding the environmental impact of common foods, such as a BLT sandwich, involves quantifying these emissions throughout its entire lifecycle.
The Carbon Footprint of Each BLT Ingredient
A typical BLT sandwich, composed of bacon, lettuce, tomato, bread, and mayonnaise, carries an estimated carbon footprint of around 1,007 grams of carbon dioxide equivalent (CO2e). The largest share of these emissions often comes from the bacon. Pork production, like other animal agriculture, contributes significantly due to factors such as feed production, methane emissions from livestock, and land use for farming, with pork generally accounting for approximately 2.4 kg CO2e per 100 grams.
Tomatoes also contribute to the sandwich’s footprint, particularly when grown in energy-intensive conditions. A medium tomato (around 80g) can account for about 230g CO2e, with emissions varying based on cultivation methods like heated greenhouses and the distances they are transported. Conversely, lettuce typically has a lower carbon footprint, although this can fluctuate depending on growing practices and transport.
Bread, usually made from wheat, involves emissions from cultivation, milling, and baking processes, adding a moderate amount to the total. Mayonnaise, an emulsion primarily of oil and eggs, has a carbon footprint that can range from approximately 2.07 kg CO2e to 3.48 kg CO2e per kilogram, with the production of its oil content being a major contributor.
Factors That Change a BLT’s Emissions
The carbon footprint of a BLT is not a fixed number, as various factors influence the emissions generated. The sourcing and origin of ingredients play a role, with imported items often requiring more transportation and thus contributing to higher “food miles”. While transportation generally accounts for a small percentage of a food’s overall emissions, air freight is a notable exception that significantly increases the carbon footprint.
Production methods also create considerable variability in emissions. For vegetables like lettuce and tomatoes, growing in heated greenhouses, especially out of season, consumes substantial energy and leads to higher CO2e outputs compared to open-field cultivation. Similarly, the environmental impact of bacon can differ based on animal husbandry practices, with more sustainable farming methods potentially reducing emissions. Organic farming practices, for instance, typically have lower greenhouse gas emissions per unit of land compared to conventional systems, although yields can be lower per product unit.
Processing steps, such as curing bacon, baking bread, and manufacturing mayonnaise, require energy that contributes to the overall carbon footprint. The type and amount of packaging used for each ingredient also add to emissions, from the production of materials to their disposal.
How a BLT Compares to Other Foods
The estimated carbon footprint of a BLT sandwich, around 1 kilogram of CO2e, provides a useful benchmark for comparison with other common food items. Meals centered on red meat, such as a beef burger, typically have a much larger carbon footprint, with beef production ranging from 60 to 99 kg CO2e per kilogram due to factors like methane emissions and land use. This places the BLT’s impact considerably lower than that of high-emission red meat options.
A chicken sandwich generally presents a lower carbon footprint than a BLT, given that poultry production has a smaller impact than pork. Vegetarian sandwich options, such as an egg mayonnaise and cress sandwich, tend to have even lower footprints, illustrating the reduction in emissions when animal products are limited or excluded.
Broadly, there is a clear hierarchy in food carbon footprints: animal-based foods, especially red meat and dairy, typically have a higher impact than poultry and farmed fish, which in turn have a greater footprint than plant-based foods like vegetables, grains, and nuts. Plant-based meals can result in emissions that are 10 to 50 times lower than those from animal products.
Making Your BLT More Sustainable
Consumers can make conscious choices to reduce the carbon footprint of their BLT sandwich. Opting for locally sourced and seasonal vegetables like lettuce and tomatoes minimizes transportation emissions and often avoids the higher energy use associated with heated greenhouses for out-of-season produce. This supports regional food systems and can contribute to a lower environmental impact.
Considering plant-based bacon alternatives is another effective strategy, as these options generally have a significantly lower carbon footprint than traditional pork bacon. If choosing to consume bacon, selecting products from producers employing more sustainable animal husbandry practices, such as those focused on reducing methane emissions or improving feed efficiency, can help mitigate its impact.
Making mayonnaise at home or choosing brands that prioritize sustainable ingredient sourcing and minimal processing can also contribute to a greener BLT. Reducing food waste by using all purchased ingredients and properly storing leftovers is also important, as food waste itself accounts for a portion of global emissions.