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Consumption

One single-use plastic bag (HDPE)

Yksi kertakäyttöinen muovikassi (HDPE)

0.1
Truecost score
Data confidence: HIGH

Carbon from well-established Ashby (2012) and UK EA (2011) LCA. HDPE is one of the most studied packaging materials.

An HDPE plastic bag produces just ~15 g CO₂e — a fraction of a paper bag's footprint. The problem is persistence: it survives 500+ years and fragments into microplastics.

Did you know? A plastic bag has just 1/4 the carbon footprint of a paper bag. The climate case for plastic is strong — the pollution case is not.
Transparent calculation

How was this number determined?

The Truecost score is calculated from absolute physical values. Each row below shows the measured value, how it was normalized, and where it comes from.

Dimension Absolute value Score 100 = Normalized Weight Weighted Confidence
Carbon Emissions 0.015 kg CO₂e 9.5 kg CO₂e 0.16 ×0.35 0.06 HIGH
Water Consumption 0.2 liters 3840 liters 0.01 ×0.2 0.00 MEDIUM
Land Use 0.0001 m²·year 51 m²·year 0.0 ×0.2 0.00 LOW
Waste 0.008 kg 5 kg 0.16 ×0.15 0.02 HIGH
Toxicity 0.1 µDALY 162 µDALY 0.06 ×0.1 0.01 LOW
Truecost score (weighted sum) 0.1

Share of your annual planetary budget

Carbon Emissions <0.01%
Water Consumption <0.01%
Waste <0.01%
Toxicity <0.01%
Source data by dimension

Where do the absolute values come from?

Carbon Emissions
HIGH
Ashby (2012): 15 g CO₂e per HDPE grocery bag. UK Environment Agency (2011): 1.57 kg CO₂e for larger UK carrier bag, but normalized per grocery bag weight (~8g) gives ~15g. Includes polymer production, extrusion, printing, transport.
  • Ashby M F (2012): Materials and the Environment, Chapter 8 — Cambridge University Press
  • UK Environment Agency (2011): Life cycle assessment of supermarket carrier bags — Report SC030148

HDPE bags consistently show lowest carbon footprint among single-use bag materials. Range: 6-40 g depending on bag size and weight.

Water Consumption
MEDIUM
58 US gallons per 1,500 bags = 0.15 L per bag. Rounded to 0.2 L including upstream oil refining water use.
  • USGS: Water Requirements of Selected Industries
  • UK Environment Agency (2011): Life cycle assessment of supermarket carrier bags

HDPE production uses <6% of the water needed for paper bags.

Land Use
LOW
Derived from petroleum. Oil extraction has minimal direct land footprint per unit. ~8g HDPE from crude oil pipeline, negligible land use per bag.
  • UK Environment Agency (2011): Life cycle assessment of supermarket carrier bags

Oil industry land footprint is real but tiny per bag unit.

Waste
HIGH
Typical HDPE grocery bag weighs 6-10g, average ~8g. Non-biodegradable, persists 500+ years in landfill. Recycling rate ~5-15%.
  • UK Environment Agency (2011): Life cycle assessment of supermarket carrier bags
  • UNEP (2020): Single-use plastic bags and their alternatives

Low weight but extreme persistence. Major source of marine litter.

Toxicity
LOW
Petrochemical production emissions during HDPE manufacturing. Additional risk from microplastic fragmentation in environment. Estimated low µDALY per bag.
  • UNEP (2020): Single-use plastic bags and their alternatives

Primary concern is environmental persistence and marine ecosystem impact rather than direct human toxicity.

Comparisons

Methodology

Based on Ashby (2012) lifecycle analysis and UK Environment Agency (2011) carrier bag LCA. Covers petroleum extraction, HDPE polymerization, extrusion, printing, transport.

Sources