Climate Action — Recycling

Recycling

Transporting, sorting and processing recycled things all emit greenhouse gases; those have to be balanced against the emissions from creating new things. So it takes careful analysis to tell whether recycling actually reduces emissions.

An upper bound: what can be recycled?

The graph below is from Berners-Lee, and explains how emissions per person break down in the UK. Have a read of the labels. As far as I can see, the only things that can be recycled by individuals are ‘other non-food shopping’ (7% of emissions) and possibly the packaging from ‘food’ (25%).

  • We could recycle all non-food shopping
  • The recycling process had no emissions
  • Each 1 kg of recycled stuff displaced 1 kg of new stuff we would have made

Packaging

Let’s try to get at this another way. I’d say that a lot of what we recycle is packaging. This estimates 2.4 million tons of plastic packaging was placed on the UK market in 2017. That’s about 36kg per person. Here’s Berners-Lee on the emission intensities of different plastics:

We’re only using the leftmost column.

The Research

As I noted, there’s really not much research here. This paper uses lifecycle analysis to determine the net emissions from recycling of source-segregated materials, that is, recycling that has been presorted into plastics, paper, etc.. Here’s the key table:

  • Lifecycle analysis is notorious for missing as much as half of emissions. Both the dark grey and light grey bars could have quite different lengths. For many of those items (e.g. paper), it wouldn’t take much mismeasurement for the light grey bar to be the longer one; in that case, recycling would increase emissions.
  • Single-stream recycling is the norm in the US and the UK. That is, paper, plastics, etc., are all mixed together. Separating these takes work! And that means more emissions, which are not accounted for in that table. Again, that means that recycling might increase emissions in many cases.
From here.
Credit.
  • The Japanese paper includes an analysis case excluding construction waste, and only finds emissions reductions of 0.7%. The details of that case are quite different to ours, though.
  • This estimates 2 kilograms (4.51 pounds) of municipal waste per person in the US. That’s about 0.7 tons a year. We estimated earlier that recycling saves around 1–2 tons of emissions per ton of recycled material, so 0.7–1.4 tons a year. That’s 0.3%–0.7% of emissions for an average person in the US.
  • We saw above that municipal waste is around 14% of total waste. Earlier we estimated all recycling, including industrial, could reduce emissions by 2%. Combining these suggests recycling municipal waste could reduce emissions by about 0.3%.
  • An average person in the US could reduce emissions by about 0.11 tons a year by recycling everything possible; that reduces 2100 temperatures on the Little Planet by about 0.012 °C.
  • An average person in the UK could reduce emissions by about 0.065 tons a year by recycling everything possible; reduces 2100 temperatures on the Little Planet by about 0.007 °C.

Beyond Arithmetic

All the research I can find considers recycling being done locally, with proper procedures. That’s not what happens in the real world. A lot of recycling is exported to developing countries. Until recently, China was the main importer, but it banned waste imports in 2018. Here are the main destinations for US plastic recycling:

From the Guardian; the article has a lot more.
From National Geographic

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criticalscience

criticalscience

Key science, with sources. Minus bad statistics. Minus shaky methodology. Minus politicisation, left or right.