What the heck is a life cycle assessment?

What the heck is a life cycle assessment? Author: Paul-Antoine Bontinck

One of the things I learnt when I got into the world of Life Cycle Assessment (LCA) nearly fifteen years ago is that we live in interconnected systems. Our decisions as consumers and as professionals have far-reaching environmental and social effects, now and in the future. Some of these effects are local, and some are global. It’s quite a daunting realisation, really.

For example, if I chose to drive to work, rather than, say, cycling, it will have very immediate consequences. Amongst other things, my car needs fuel. Pollutants like greenhouse gases and particulate matter will be emitted to the air as the fuel is combusted. At the local level, particulate matter will affect people’s health in my immediate surroundings. At the global level, we now all know about greenhouse gases and climate change. Of course, this is only a part of the whole picture. Cars are very complex products, and so is the fossil fuel supply chain.

Other decisions set a path for the long term. For instance, building brown coal power plants in the mid-20th century in Victoria still affects us today. And despite a significant increase in renewable power, it will affect us for a while yet.

When Tim Grant trained me on LCA nearly 15 years ago, he was often quoting the Matrix (yes, I know, nerd!). For those familiar with that universe, diving in the world of LCA is very much like taking the red pill. It forces us see the world in a different way, to question our biases. It divulges the secret life of things. It is uncomfortable, and at the start it leads us to question decisions which used to make us feel good. Great, my paper bag is ‘biodegradable’, and it’s ‘natural’ – but why is that a good thing? Can it be quantified?

At the core of any LCA is the idea that if, as humans, we want to reduce our impact on the world, we should base our decision on solid evidence. Because when it comes to those complex systems, our gut feeling is often wrong. LCA models can be used to measure the environmental effects of our decisions. This insight can be used to answer questions, like what are the consequences of switching from paper to plastic shopping bags? What about comparing single use to reusable bags?

LCA models can help tease out which part of the system is important, what drives a particular outcome. They can also help identify opportunities to reduce environmental impacts, while ensuring this does not have unwanted effects elsewhere in the economy.

By nature, LCA models are simplified representations of extremely complex production systems, so they are always ‘wrong’. But those models are still very powerful, because they allow to ascertain whether our decisions are likely to help us move in the right direction, towards a more sustainable future.