Background

As well as a gradual shift towards a generally warmer climate in most parts of the world, including in Aotearoa New Zealand, the impacts of climate change will likely be most keenly and immediately felt through changes in extreme weather.

Aotearoa New Zealand is highly vulnerable to the damage inflicted by extreme rainfall, flooding, temperature, and wind. Between 2007 and 2017, insured and economic losses due to flooding and drought totalled more than $4.7bn, of which approximately $840m was estimated as attributable to human influence on climate. Aotearoa New Zealand is also particularly vulnerable to the impacts of extreme rainfall on transport networks: the country depends critically on a relatively skeleton roading infrastructure which can easily suffer devastating impacts if blocked by landslide or flood, with severe consequences for transportation and economic losses as a result.

Research Aims

The aim of this research project is to produce a novel data set of future climate and weather extremes, for use by stakeholders and other researchers, that provides national-scale information for Aotearoa New Zealand using an unprecedented amount of climate model information.

This will provide New Zealanders comprehensive information on how we expect climate and weather extremes to change in the coming decades, and assist New Zealanders to build their capacity to adapt to climate changes ahead, and guide planning and policymaking, including for climate change mitigation.

The project team will create new, very large data sets of the ‘weather@home Australia/New Zealand’ regional climate model, sufficient to simulate and count very rare weather extremes. We will apply statistical fits to these data sets, test how well these fits perform, and then subset the large data sets to mimic the smaller data volumes typically obtained from other climate models, including the New Zealand Earth System Model. This will help us to extract as much information as possible from these smaller data sets and enable us to compare different models. We will communicate the results in a new way, seeking to describe expected future climates in terms of climates that may already exist today but in other locations.

We will inform and consult with the general public regarding our findings and encourage their participation in climate change science via the ‘weather@home’ project, which allows anyone to run a climate model on an ordinary PC at work or home, through distributed computing.