The Measured Impact of Reuse

Reuse has hard numbers: over 50% CO2 reduction across the full life cycle, 12 returns for a milk bottle, 98% refillable and returned in Denmark, and 970 tonnes of plastic saved by one 1991 refund scheme.

The headline figure is the CO2 one. Research has shown that reusing a product can reduce CO2 emissions and carbon footprint by more than 50% relative to the complete product life cycle. That is measured across the whole cycle, not just the disposal step.

Container return counts show the same effect at a smaller scale. On average a milk bottle is returned 12 times, whereas a lemonade bottle with a 15p deposit is returned on average only 3 times. The deposit size and the container's role change how many trips it makes before it leaves circulation.

Denmark is the mature-system example: 98% of bottles are refillable, and 98% of those are returned by consumers. High refillable share and high return rate reinforce each other — one without the other does not produce the same result.

At retail level, Sainsbury's penny back carrier-bag refund scheme of 1991 was reported to save 970 tonnes of plastic per annum. In 1991 Sainsbury Ltd extended the bag refund to a voucher scheme, estimated to raise plastic savings to 2500 tonnes per annum.

The practical takeaway is to track your own stream the same way — by kept-and-released counts, not by anecdote. A household log over a few months shows which material actually grades well and is worth building a second project from.

• Over 50% CO2 reduction from reuse across the full life cycle.
• 12 returns for a milk bottle; 3 for a 15p-deposit lemonade bottle.
• 98% refillable and 98% returned in Denmark.
• 970 tonnes of plastic saved per year by the 1991 carrier-bag refund; 2500 tonnes estimated after the voucher extension.

Further reading

• Sort and Grade What You Throw Away
• Three Starter Projects