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Packaging, the leading application of plastics has a global market size exceeding US$240B. Over half the plastic packaging is used in the food and beverage sector. Industrial packaging and non‐food consumer packaging, each account for less than half of that volume. About 56% of plastic packaging is PE, with PP (22%), PET (10%), while some PS is also used (Mackenzie 2019).

Packaging addresses a key problem of the Anthropocene, the unprecedented wastage of food in the supply chain as well as by consumers. Globally, an estimated 1/3 of food intended for human consumption invariably ends up as waste (Gustavsson et al. 2011); food wastage in the US is even higher, by at least a third, compared to that in other countries. Along with food, all the resources, including fossil fuel invested in their production, are also wasted and it is critical to minimize this waste. An industry study in the US recently found significantly less food wastage with packaged, compared to unpackaged, food (Ameripen 2018). Plastics packaging achieves this reduction primarily by extending the shelf life of food throughout the supply chain and by managing portion sizes. The weight fraction of packaging needed for this purpose is relatively low, compared to that of food or beverage. This is also true both in terms of the monetary, and the environmental cost of the package, compared to that of the food. Life cycle analysis (LCA) comparing different packaging materials for beverage, highlight the minimal environmental impacts of plastic packaging relative to that of the food it protects (Ghenai 2012; Sivenius et al. 2011; Vignali et al. 2016).

Spoilage of produce and meats is controlled by reducing the oxygen they are in contact with, to dramatically increase their shelf life. One way to achieve this is by vacuum packaging food with flexible plastic films having high barrier properties. Vacuum sealing extends the shelf life of refrigerated vegetables three‐ to four‐fold and frozen meats from weeks, to months, or even years. Fresh meats in refrigerated displays, for instance, typically retain their desirable color only for three to seven days. Modified atmosphere packaging (MAP) used to pack the meat in an atmosphere of high oxygen (70–80%) with 20–30% CO₂ gas, extend its shelf life up to two weeks. The oxygen‐rich environment in the package retains the red color of meat, the criterion used by consumers in judging its freshness, for a longer duration. Transparent skin packaging of cured meat products, is in fact, only possible with plastic barrier films. Vegetable and fruit packaging with MAP helps reduce the use of preservatives in produce. Other approaches such as gas flushing, scavenging/desiccant sachets, or on‐package valves are all used extensively with plastic packaging to modify the atmosphere inside the package.

The use of any packaging incurs an environmental cost and often creates a post‐use solid waste issue as well. In Figure 1.14, E₁ is the embodied energy of the material made from feedstock such as aluminum from ore, or PET from fossil fuel, and E₂ is the processing energy expended to form the material into the package. Energy expenses E₃ onwards are the increments of energy expended in display at store, transporting, cooling prior to use by consumer, cooking, and its post‐use disposal. Quantities C₁, C₂, and C₃ (onwards) are the corresponding emissions associated with each step, that include the carbon footprint, the water footprint, and the solid waste generated. The scheme allows a simple comparison of the footprint of different packages such as glass or plastic, provided detailed, reliable, inventories for each step are available. Reported data for (E₁ + E₂) and (C₁) for different beverage containers (Ghenai 2012) are shown in Table 1.8. Note however, that these values are based on LCA and therefore, may vary with location, time, and technology used (Figure 1.14).

The limited analysis has several shortcomings, but shows the plastic jug to have the second‐lowest embedded energy as well as carbon emissions. Not captured in Table 1.8 is the water demand, especially in pulping and bleaching of paperboard, as well as the impact of toxic releases from any of the steps. Paperboard enjoys the unique advantage of being based on a renewable feedstock, partly reflected in the value of E1 (it is also biodegradable in the environment). These estimates assume that only virgin materials are used, and if recycling is included, given the high contributions of of E₁ and C₁ to EE nd EC, these estimates can decrease considerably.

Figure 1.14 Schematic representation of manufacturing a package.

Table 1.8 Energy and carbon footprint associated with packaging milk in various containers. (The percentage of embodied energy and carbon associated with material production phase is shown in parantheses).

Container	Mass of package (kg)	Volume L	Embedded energy (1010 J) (E1%)	Carbon footprint (kg) (C1%)
HDPE jug	0.051	0.946	2.95 (82.2)	1219 (67.7)
Aluminum can	8.1	50	17.52 (95.9)	10263 (94.7)
Glass bottle	0.41	1	5.82 (68.7)	3820 (62.0)
Paperboard carton	0.057	0.942	0.65 (84.8)	278 (73.4)

Data from Ghenai, 2012

Using packaging with a high environmental cost is justified with food that also has high EE (MJ/kg) and a large carbon footprint (e.g. meats, cheese, coffee, chocolate) as it minimizes waste, and extends shelf life, assuming the consumer will responsibly dispose the packaging waste. If responsible disposal can be assured, plastics would indeed be the ideal packaging material available. A common product that does not conform to the above criteria is bottled water, a popular beverage in the US, with 13.85 Billion gallons sold worldwide in 2018. The environmental cost of the packaging, however, is several orders of magnitude higher than that of the water. The embodied energy of the PET bottle of ~8 MJ/L is enormous by comparison to that of the water of (<0.2 MJ/L) Also, the carbon footprint of the PET bottle is ~42 kg CO₂‐e while it is negligible for the water! When transportation, labeling, display, and promotional costs are added, the environmental price tag of bottled water is unacceptably high, especially for water imported from other countries. It is still popular because of its convenience in serving large numbers of people and the misperception that it is more hygienic compared to tap water. An interesting, related comparison is between the environmental merits of paper grocery bags versus plastic bags is pointed out in Box 1.3.