The study identifies real-world export routes and modes of transport – including land emissions both within the UK and China and shipping emissions – and calculates CO2 emissions for each transport stage.
A number of scenarios have been assessed to produce a range of estimates and sensitivity analysis has been undertaken to test the robustness of the conclusions.
The CO2 emissions associated with transporting one tonne of recovered paper from the UK to China are estimated to lie between 154kg and 213kg of CO2. The emissions associated with transporting one tonne of recovered plastic bottles range between 158kg and 230kg of CO2.
These CO2 emissions levels represent less than a third of the carbon savings from recycling identified by a majority of the life cycle assessments (LCAs) reviewed in the study (Table E1). This suggests that there are CO2 savings to be made from recycling, even if the recovered materials have to be transported to China. This conclusion becomes even more compelling if the reverse haulage nature of recovered materials export is taken into account. Due to the trade imbalance between the UK and China, the majority of containers heading back to China are empty. The conventional method of calculating transport emissions is to include the emissions associated with transporting the entire vessel weight (‘absolute’ emissions), not just the cargo.
However,since the ship and containers will be returning to China, regardless of whether or not the ship is loaded with recovered materials, thecase can be made that only the emissions incurred in shipping the incremental cargo weight (‘marginal’ emissions) should be considered.