5 June 2024

This is the first of a series of posts on complexity. We’ll be exploring some of the ways that studying complex systems gives us a more nuanced way of understanding the world, how this is relevant to all our lives, and the unique contributions we can make to this new way of understanding the world from Aotearoa New Zealand.

An aeroplane is pretty complicated. The large commercial planes that criss-cross our skies are made up of millions of parts, each one carefully designed and engineered. There are hundreds of years of scientific enquiry behind these machines that lift us off the ground and transport us at tremendous speeds around the world.

Each part of an aeroplane has a particular purpose, and contributes to achieving flight. You can reduce an aeroplane to the parts that make it up, and you can reduce flight to four basic principles: lift, weight, drag and thrust.

Aeroplanes are a great example of understanding the world by breaking it down into parts, and then understanding the whole system as the sum of these parts. Over the last few centuries, scientists have gotten pretty good at this approach.

But if you took an aeroplane apart, it would just be a big pile of parts again. Without a team of humans who understand how to rebuild it, this pile of parts would continue being a big pile of parts, rather than an aeroplane.

An aeroplane is very complicated, but it’s not complex. In the 21st century, as human societies are growing, becoming more interconnected, and having an increasing influence on planetary systems, it’s complexity that we need to understand.

An illustration showing aeroplane parts laid out over blueprint.

On planet Earth, we’re surrounded by big piles of water. These big piles of water are made up of water molecules. As these molecules are heated, they rise up into the sky, and form clouds as they cool. They travel around the world, and become mist, fog, rain, snow and hail. They coat mountaintops, and they feed plants. They carve out landscapes, and they flow down rivers and back into the sea.

Where aeroplane parts create aeroplanes, water molecules are one of the components that create weather, and our climate. Weather is different from an aeroplane because it doesn’t need anything external – like a group of aeroplane engineers – to create it. This is why weather is a complex system, and an aeroplane isn’t. And where aeroplanes are reasonably consistent, the weather is never the same. Those piles of water molecules interact with each other and other elements of the weather system to produce infinitely different weather patterns.

Complex systems are all around you. And you as a human have arisen through the behaviour of complex systems. Biological cells organise themselves into animals and plants, and can create wondrous structures like the human brain.

When biological cells have self-organised into humans, those humans create societies, and those societies interact with the systems around them to influence things like the climate system, which in turn influences those societies. Everyone and everything exists within this interwoven system of systems with complex relationships that feed back and influence each other. These interwoven systems challenge our common understanding of cause and effect.

An illustration showing the journey of a water molecule into weather.

When Cyclone Gabrielle ravaged the local environment in Aotearoa New Zealand in 2023, the complexity of the situation became strikingly evident. Many factors determined the extent of the damage and the effectiveness of recovery efforts, from the interactions of atmospheric conditions to the vulnerabilities of built environments and the different ways that communities reacted.

Where wind patterns, topography, infrastructure resilience, and human actions and decision-making interact, they give rise to outcomes that cannot be predicted by analysing each component in isolation. We call this emergence, an important process resulting from the relationships within complex systems.

A better understanding of complex systems can help us to see the whole context of situations like extreme weather events, including their emergent properties. This will help us to better predict, understand and act when disasters strike.

To understand complex systems, breaking them down into their individual bits doesn’t cut it, as it is the relationships between the parts that have the most influence.

The challenges that we face in the twenty-first century are complex. The interrelated problems of economic crises, social inequality, food insecurity, migration, urban and rural living conditions, and globalisation have shown us the limitations of understanding the world as only complicated.

Although we have become very good at understanding and building the complicated, we have more work to do on understanding and acting on the complex. How does anything, like disease, information, and cultural practices, spread through systems?

Over the last century or so, the study of complex systems has given us a detailed way of understanding our world. We have learned a lot about how complex systems behave which can assist prediction and change. We have learned that how they evolve is quite similar across many different areas, and that understanding one system can give surprising insights into another. As we have learned more about complex systems behaviour, we have also learned more about how this behaviour is tied together through theories of complexity that enable structures and processes to be defined, detected and studied.

As humans grow as an influential force on Earth and beyond, we need to better understand our relationships with each other and with the systems that we encounter. The developing field of complex systems is giving us the concepts, language, and tools to do this. In this blog series, we will explore some of the foundations of complex systems and how they can help us to understand our world.


A collaboration between Te Pūnaha Matatini Principal Investigators Anna Matheson and Markus Luczak-Roesch, and illustrator Hanna Breurkes. Edited by Jonathan Burgess.