Months on from the series of devastating downpours that became our “storms of the century”, communities are still picking up the pieces, but the question remains: how much did climate change worsen the damage?
While we were quick to declare our summer of storms a “climate change disaster”, scientists aremore circumspect. At best scientists can cautiously conclude that climate change is only partly responsible for Cyclone Gabrielle’s damage.
An international and New Zealand research team explored the role of our heating planet in the extreme weather we saw on the East Coast. They stopped short of stating the precise contribution of climate change. So what other factors were at play?
This World Weather Attribution Group analysis tells us that the catastrophic damage, economic cost, and loss of life were caused by failures in our flood protection systems and shortcomings in our infrastructure which were ill-equipped to withstand February’s floodwaters.
Land use changes that reduce soil stability combined with deforestation and forestry slash also played a destablising role.
Looking at our urban centres, the summer deluges fulfilled decades-long prophecies by water engineers. They have known all too well that intensification and more asphalt without green spaces and bigger pipes meant the capacity of our stormwater network would be exceeded.
Despite evident dangers, development still takes place on floodplains or too close to the ocean. Replacing streams with pipe is still commonplace in New Zealand. When councils attempt to change rules to better future-proof against flooding they face fierce opposition from the development community and existing homeowners.
We can throw around nifty catchphrases like ‘sponge cities’ in our search for a solution to flooding, but our urban areas cannot absorb record rainfall. As Engineering New Zealand expert Stu Farrant puts it: “The name says it all – a sponge has a finite limit to it, at which point the water sheds off.”
Dramatic changes to how and where we build our communities are called for. No matter how much we mitigate climate change, many homes will flood. The mauri of water is more powerful than we are. We must adapt to be resilient.
■ Anne-Elise Smithson is a Wellington-based environmentalist and former elected representative to Auckland Council.
