It is used continuously – in the news, when you visit the supermarket, in advertising. We sort of all get what it means – it is something good, aspirational, guilt-free. Sustainable packaging, sustainable travel, sustainable clothing, sustainable products. It means it is good for the environment, good for the planet, that we’re doing something positive. But how sustainable is ‘sustainability’?
Dictionary definition of sustainable: (ability to) maintain or keep going continuously.Oxford English Dictionary, 1994
In an environmental context, sustainability is the ‘avoidance of the depletion of natural resources in order to maintain an ecological balance’ [Lexico.com, 2019]. Put simply, it is using less, reusing wherever possible and, finally, recycling more. The aim would be to generate zero waste and also minimise the extraction of natural resources – a closed loop. Given the dictionary definition of sustainable, we are still far from achieving this and there are arguably few truly sustainable examples out there.
Reduce, Reuse, Recycle
The 3 Rs (reduce, reuse and recycle) were first coined to prevent solid waste and redirect unwanted products or by-products from landfill – now more commonly called resource recovery. The 3 Rs do, however, have a much wider application. Energy exerts the biggest environmental cost so reducing energy consumption will have a huge environmental impact – we will burn less fuel thus using less natural resource and reducing emissions of gases linked to climate change. Even clearing out your email mailbox will help reduce energy use as fewer servers need to operate!
Closing the loop
Linking processes up can help to reduce further energy loss or otherwise utilise what would be wasted resources (i.e. resource recovery). For instance, heat is a by-product of many industrial processes but can be used to heat homes, heat glasshouses or even heat surfaces to prevent ice formation (pavements, roads, runways). We are all familiar with the massive cooling towers of power stations but what if this heat (and carbon dioxide) could be redirected to nearby glasshouses to boost food production and utilise what would otherwise be wasted energy. Combined heat and power plants won’t solve the problem of resource depletion but joining two, or more, separate processes together could at least halve demand and is one step closer to a sustainable future. A number of wastewater treatment plants are beginning to do this (e.g. Anglian Water) while a number of industrial processes have been doing this for a while (e.g. British Sugar).
More efficient vehicles, equipment and machines can all contribute to reduced energy demands and move us closer to living sustainably. However, new energy-efficient products need to be manufactured and hence consume energy and other natural resources in their production. How is the energy generated for factories manufacturing, for example, electric vehicles, energy efficient LED screens or even solar panels and wind turbines? Where are the metals, plastics, rare earth minerals, magnets, glass etc. sourced? Understanding the full life-cycle of all products – from what they are made of and where/how the resources used to make them are sourced to the manufacturing process, transportation to point of sale, and end-of-life disposal – need to be fully understood to ascertain if a product is really sustainable. Reusable travel mugs made of recycled plastic are undoubtedly much better for the environment than single use disposable plastic cups but they can only be considered sustainable when their whole life cycle is considered – from sourcing raw materials (in this case, waste plastics) through the manufacturing process (which will use energy and water) and transportation to point of sale, then use (including washing of mugs after use) and ultimately disposal (to landfill, incinerator or recycling into another product?).
Sustainability in Gardens
We are a long way off closing the loop but we can certainly improve how we do things to reduce inputs and outputs from our systems. Gardens are very well placed to do this. We can already do a lot within gardens from improved water management (collecting rainfall in the garden and storing for later use, from watering plants to cleaning, use in toilets, and even as a reservoir to compensate natural flows or reduce flood risk downstream) and soil management (creating own leaf mould and mulches within gardens). The purchasing power of gardens should not be underestimated. We can ask our suppliers about their manufacturing processes to determine their environmental footprint: if we encourage our suppliers to make changes, we will all benefit from improved environmental performance. If we group together and, as an industry, insist on change, we can make an even bigger impact.
There are two areas of significance to gardens where changes are being made, some as a result of the horticultural industry coming together to insist on change from suppliers. One is single use plastics and particularly plastic plant pots. A simple change in colour of the pots, as championed by the horticultural sector in response to a growing awareness of the environmental cost of plastic pollution, mean that pots can be separated for recycling where recycling facilities exist. In the UK, much of our plastic is exported, often to countries with little or no environmental regulations. We need more facilities in the UK that can reprocess our plastic waste and reduce the environmental cost of plastic use. If we can reuse our pots, that is even better while reducing plastic pot use could be potentially even more beneficial – can we grow plants using more environmentally friendly materials? Plastics might actually be okay in some situations compared to other materials when sourcing, manufacturing, transporting and end-of-life disposal are considered.
Growing media are another area that is currently undergoing significant change. Peat has been a staple of potting growing media but peat is not a sustainable product, taking centuries to form (as well as acting as a significant carbon sink if left in situ in peat bogs). Alternatives to peat, however, have their own set of sustainability issues. Coir, for instance, is a by-product of coconut growing but is transported vast distances and also uses large amounts of water in often water stressed regions when processed for use in growing media. As with all the examples of sustainability, the issues are a lot more complicated and convoluted than they first appear.
As part of PlantNetwork’s Sustainability Programme, we will look at different sustainability issues over the next few years, through a combination of blogs and events. We would like to hear from the PlantNetwork community on what you are doing to address these issues and what you would like to hear about, so get in touch. If you have found a more environmentally friendly alternative to a current product or practice or are working on a new solution, let us know.
The next Sustainability Programme blog will look at peat-free growing media so please get in touch and let us know what you are doing in your garden….
Prepared by and for PlantNetwork, November 2019
[Main picture: plants in taupe pots]
Bigger than the O2: giant greenhouses to grow 20 tonnes of tomatoes a day, The Guardian, 03 October 2019
Our co-products: Creating value and driving sustainable efficiency, British Sugar, Accessed November 2019.
Reusable coffee cups aren’t entirely eco-friendly, The Independent, 13 August 2019.
Plastic Pot Initiative the Taupe Pot, Horticultural Trades Association (HTA), June 2019.
How the UK is moving towards recycling most of its plastic waste, The Telegraph, 21 March 2019.
Natural England’s role in meeting climate change targets, Natural England blog, 21 June 2019.
Guidance on applying the Waste Hierarchy, Defra (2011). Accessed November 2019.
WRAP: At the forefront of the circular economy, WRAP. Accessed November 2019.
What is a circular economy? A framework for an economy that is restorative and regenerative by design, The Ellen MacArthur Foundation, Accessed November 2019.