A new report that brings home the impact of climate change in Wairarapa in never-before seen detail has just been released by Greater Wellington.

Commissioned by Greater Wellington and written by NIWA, the report provides the latest update on the climate science for the Wairarapa since last year.

It comprises state-of-the-art climate change projections, with a suite of high resolution maps, providing a targeted view of the different climatic zones and climate change impacts across the vast Wairarapa geographical landscape.

Dr. Alex Pezza, Greater Wellington’s senior climate scientist, says that while the report doesn’t provide new modelling since NIWA’s previous climate change modelling, its value lies in the clarity with which it presents the impact of climate change in the region.

“The clearer we can be in presenting the stark reality of climate change in Wairarapa, the better people will understand what the future looks like and the more likely they will be to change it for the better.

“So If people can grasp the scientific message from a position of strength and balance, they will naturally contribute towards a better future in their local community”, says Dr Pezza.

As well as high resolution maps, the report is supported by a short, yet detailed explanatory ‘user-friendly’ video which provides an overview of NIWA’s scientific projections. It animates different future scenarios based on known changes plus additional different impacts that will affect agriculture, water resilience, environmental, economic and community resilience.

Greater Wellington Climate Committee Chair, Cr Thomas Nash, says that hammering home the climate change message is vital.

“This report reinforces what we know – that we can already see rising temperatures and the intensification of extreme weather events. We also know that the sooner we all bring our emission generating activities into line with the reality of our changing climate, the better off we will be long term.

“One thing is certain - natural infrastructure, like healthy soil, forests and wetlands – will be more and more important in a climate stressed world. Natural infrastructure is the best value infrastructure money can buy and it not only stores carbon, but protects against drought and flooding and boosts biodiversity.

“As part of the 30-year Wellington Regional Growth Framework we are undertaking serious regional climate planning, both on emissions reduction and on adaptation. Reliable scientific data is crucial for this planning work so this new updated report is an important contribution.”

To reflect the changes projected for Wairarapa’s climate, a Water Resilience Strategy was recently approved by the three local councils, local iwi and Greater Wellington. This strategy principally evolved from both the Wairarapa Economic Development Strategy and NIWA’s earlier climate change work for the entire Wellington region.

Work has just begun on planning implementation of Water Resilience Strategy, covering ‘green’ projects such as plantings, though to infrastructure such as water supply pipe repairs. NIWA’s latest Wairarapa climate change projections confirm the nature and scale of the efforts needed to help mitigate climate change effects.

Greater Wellington’s Wairarapa Committee Chair, Cr Adrienne Staples, says that Greater Wellington is working with local communities to mitigate one of the key threats outlined in the report, the likelihood of more intense rainfall events and the potential for resulting flooding.

“Given the impact of intense rainfall on our rivers, it’s no longer viable to focus solely on engineering solutions to flood management. So we’re looking to the future by enabling, within limits, the natural flow of our rivers, developing natural solutions to the impact of flooding and adapting land use to the conditions of the future.”

Report link: https://www.gw.govt.nz/assets/Climate-change/WairarapaCCFinalReportcompressed.pdf

Video link: https://vimeo.com/582743505/afdf2e683e

What is Greater Wellington doing about the climate emergency?

· Greater Wellington has identified four key overarching priorities for the next 10 years including responding to the climate emergency. As a consequence, the Council has set an organisational target to be carbon neutral by 2030 and climate positive by 2035.

· To achieve these goals, Council is looking to decarbonise the public transport fleet and remove grazing from the regional parks.

· Beyond these areas of direct influence, Council is working closely with its territorial authority partners, including the Wairarapa, to increase consistency in climate action around the Region and with central government and mana whenua partners through the Wellington Regional Leadership Committee.

· Charged with overseeing the implementation of the Wellington Regional Growth Framework, this Committee will seek to build a low-carbon, climate resilient urban form over the long term.

Summary of Wairarapa’s climate change projections:

· Drought potential is projected to increase across the Wairarapa, with annual accumulated Potential Evapotranspiration Deficit (PED) totals increasing with time as greenhouse gas concentrations increase.

· Annual average growing degree days (GDD), which are a good indicator of heat available for plant growth, are projected to increase. The upper-range increases would see areas of the Wairarapa observing GDD totals comparable to those observed historically (1981-2010) in parts of Northland, with significant ramifications, including opportunities, for agriculture.

· Increasing maximum temperatures will result in more hot days (daily maximum temperature over 25°C) and extreme hot days (daily maximum temperature over 30°C). By 2040, up to 30 more annual hot days are projected, with up to 70 more annual hot days by 2090 for high emission scenario. By 2090, extreme hot days are projected to increase by up to 3 days for low emissions or up to 25 days for high emissions.

· The average number of frost days are expected to decrease with time, as greenhouse gas concentrations increase. The largest decreases are projected for high elevation and inland locations. Overall, up to 10 fewer frost days per year are projected by 2040 for a low emissions future, with up to 35 fewer frost days by 2090 for a high emissions future. Smaller decreases are generally projected for coastal locations because fewer frosts currently occur in these locations.

· Projected increases in maximum temperature are greater than for minimum temperature, resulting in an enhanced day- night range.

· Heavy rainfall events are generally projected to become more extreme in the future. By 2040, the magnitude of heavy rainfall events is projected to increase by up to 15%. By 2090, heavy rainfall event magnitude is projected to increase by 3-30%.

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