19 April 2018
I remember when tax breaks were introduced to encourage drivers to switch to diesel cars. It was with the best of intentions, aiming to reduce CO2 emissions and address climate change. The action made a difference, but in choosing to focus on one environmental impact, it neglected another – air pollution. In recent years, evidence has grown that other emissions from diesel engines, notably nitrogen oxides, are significant contributors to air pollution in cities, and clean air has become a higher political priority. As a result, car manufacturers are now moving away from the diesel engine. Of course, a more sustainable solution is to use public transport in cities!
That’s why we need to think carefully about how we solve the plastic waste problem in the wake of Blue Planet 2. People are both enraged and inspired by ocean plastic pollution, and have been modifying their personal behaviour and flexing their consumer muscle. I have moved to a reusable coffee cup, though not gone as far as berating supermarkets for encasing coconuts. We are all understandably keen to do our bit. But some of the solutions we are turning to may not be the right ones.
Solution one: plastic-free fresh produce! One idea is to abandon plastic packaging for fresh produce in supermarkets; but it turns out this is not straightforward either. Consider the humble cucumber. The Cucumber Growers’ Association has calculated that only 500 tons of plastic gets wrapped around UK produce every year. However, it extends the shelf life of cucumbers from three days to 14. If you weigh up the energy, water and money that go into growing, transporting and storing cucumbers, you soon see that wasting cucumbers is not a good option and that extending their shelf life is. And guess what? Food waste is a huge cause of climate change. If food waste were a country it would be the third biggest global greenhouse gas emitter, after China and the USA. That’s not to say that plastic is always the best option, just that we need to weigh up the options carefully.
Solution two: compostable packaging! This seems like a no brainer. Make it compostable and it won’t sit in landfill for 500 years. Plus if it gets in our waterways, it will simply disappear. Wrong! Compostable plastics actually release greenhouse gases as they biodegrade. Plus complications arise if these alternative materials get mixed with conventional plastics in recycling routes. By their nature, they are designed to break down, not to be recycled into, let’s say, a damp proof membrane to line your floor. Now, let’s just imagine the unintended consequences of that! There are some contexts where it makes sense to use compostable material, but again it needs careful consideration.
When we make decisions about materials, we have to consider all the environmental impacts. It’s easy to make a decision based on one aspect while neglecting others, and thereby create unintended consequences. We need to recognize where our knowledge is incomplete. For example, we need to carry out more research to better understand the trade-offs between food waste and packaging, and the impact of plastics on the marine environment, whether it’s large pieces of plastic or small, the effects on marine wildlife or the knock-on effect humans. And researchers need to use the right tools. For example, life cycle assessment can be a useful tool, but we need to choose the right tool for the right context. I want to collaborate with partners to help bring together more evidence on the environmental impact of plastic packaging so that we can all make more informed decisions.
All this is no reason to do nothing, though, far from it. There are clear wins to be had from actions like purchasing fewer single-use plastics, not using plastic straws, and reusing and recycling plastic bottles. If all the plastic bottles that are not collected for recycling in the UK each year were placed end to end, they would go around the world 31 times. It’s just that doing the right thing for people and planet will be more like designing the peace than declaring a war on plastics.