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Blog Post April

Unpredictable, extreme, severe and, more frequent – weather is changing and we need to plan for it

By Isobel Bruun-Kiaer

Twitter: @climateNZ


"While the annual precipitation in the Bay of Plenty is expected to decrease with climate change,the frequency of extreme rainfall events, and subsequent flooding, is projected to increase. The expected changes in rainfall patterns in the Bay of Plenty have significant implications for planning and development, including stormwater infrastructure."

(Adaptation in Tauranga, Ministry for Environment 2008)


Cyclone Cook MetService National Forecast, 13th April 2017
Source: New Zealand MetService

Cyclone Cook, Ex-Cyclone Debbie, the Tasman Tempest, the Hawkes Bay fires, and the Port Hill fires - just some of the extreme events that New Zealand has had to contend with already in early 2017.

Wherever you are in the world, you may have heard about these events in the media. For many people across NZ they have been devastating – real life events causing flooding, land slips, power outages, fallen trees, blocked roads, storm surges, coastal inundation and sink holes.

In March, the Tasman Tempest in March brought more than 150% of the normal rainfall for the month with more rain falling in 48hours in parts of North Island than would normally fall the entire month. Within the next couple of weeks came Ex-Cyclone Debbie with more rain, followed by Cyclone Cook with yet more rain, making landfall in Tauranga.The frequency and severity of these types of events are projected to increase.

This means, such severe and extreme events might become more devastating and more regular.

This has consequences for people and places. And, not only in New Zealand.



Global temperatures are on the rise…
Source: ClimateCentral


No single weather event is caused by climate change - weather and climate have always been variable. But, the warmer sea temperatures and a warmer and wetter atmosphere (as you can see above) are contributing to more extreme and more frequent weather events.

So, what do we do about it?

Preparedness .Information sharing. Emergency planning. Long term measures. Resilience.

There is no single solution, but all of the above play a part in how severe the impacts will be. Planning has a central role in this.

One of Tauranga's long term responses to planning for flooding from such weather events seems to have paid off. Although Cyclone Cook made landfall in Tauranga, the city's improved stormwater infrastructure and planning for a 1 in 100 year event has seemed to alleviate the flood impact felt by the local community

Following a severe flood event in 2005, Tuaranga put in motion an initiative to strategically reassess stormwater management across the city taking into account climate change and integrating this into planning for the city's growth. Working in partnership with the regional and district councils, Tauranga City Council has factored in increased high intensity rainfall into their planning blueprint for the next 50 years of growth and development.

There are two elements to this:

1. Flood Hazard Mapping: understanding and modelling water movement, catchments and infrastructure around the city in relation to a 1 in 100 year storm event (example below).


Tauranga Flood Hazard Map
Source: Tauranga City Council


2. Physical interventions: making space for water


Stormwater infrastructure doing its job
Photo: Rosalie Liddle-Crawford/SunLive


While some areas in the Bay of Plenty region were heavily flooded by Cyclone Cook, the City of Tauranga did not fare too badly and this was in part due to it's measures to deal with draining extreme levels of stormwater. This is just one example of a response to the potential impacts of climate change, imagine what could be achieved by integrating this into other aspects of planning – not just for natural hazards, but looking towards the health and well being impacts of climate change.

The limits of planning are what you make them. The opportunities of planning are there to be grasped! Building resilience to climate change is about more than preserving the status quo, it's a chance to enable improved governance for current and future populations and the environment. It is the chance to be progressive.

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