Droughts in Aotearoa
Scientists are using various tools to try to predict what future droughts could look like for Aotearoa. Obtaining an accurate risk assessments is a complex process, and we should not just be relying on recent droughts as a guide.
This article has been republished from The Conversation under Creative Commons licence CC BY-ND 4.0 and is written by Adam Brown, (PhD Candidate, School of Science, University of Waikato), Dave Frame (Professor of Physics, University of Canterbury) and Luke Harrington (Senior Lecturer in Climate Change, University of Waikato). It was originally titled Future big droughts may be worse than we think – NZ’s past shows why.
For an agricultural nation like New Zealand, severe drought is one of the most ominous consequences of a warming planet.
Effects of drought
Reduced amounts of rainfall can cause drought conditions. This impacts pasture forage. Pictured is Scott Farm during an extreme dry event in 2013.
The Climate Change Commission’s latest national risk assessment points to these events becoming more intense over time, particularly in the country’s drier northern and eastern regions.
Recent events offer a glimpse of what this can look like: browned paddocks, shrinking reservoirs, dried-out riverbeds and farmers struggling for feed. They have also illustrated the heavy economic toll drought can take.
Feed shortages amid an extended 2007–08 drought, which hit Waikato particularly hard, quadrupled silage prices and cost the national economy several billion dollars.
Another drought four years later, this time covering the entire North Island, was later estimated to have squeezed national economic output by as much as 0.7% of GDP.
The Reserve Bank has since used that 2012–13 event as a plausible worst-case drought scenario in some agricultural lending-risk assessments.
But looking much further back reveals evidence of significantly more severe meteorological droughts – prolonged periods of unusually low rainfall – occurring in the early 20th century.
Our new research suggests some of New Zealand’s most extreme drought history has effectively been overlooked in modern policymaking.
Reconstructing New Zealand’s drought past
When scientists and planners assess how severe a drought is, they often rely on a dataset called the Virtual Climate Station Network. It uses rainfall, temperature and other weather observations to build a detailed picture of climate conditions across New Zealand.
While this is an invaluable tool, reliable data for many variables only stretches back to the 1970s. That means many modern drought assessment methods are less useful for understanding severe events that occurred earlier in the 20th century.
To build a clearer picture of these earlier droughts, we focused on a single, reliable metric: rainfall deficits. These have been recorded by thousands of rain gauges across New Zealand dating back as far as the 1860s.
Soil moisture deficit map
A soil moisture deficit map indicates whether soils have a water surplus, are at field capacity or have a water deficit.
Next, we selected weather stations with long and reliable records, including at least 70 years of data and observations dating back before 1914. This produced a network of 97 high-quality stations across the country.
Lastly, we compared historical rainfall data against long-term averages to see how drought conditions built up over weeks, months and longer periods.
Contrary to the idea that New Zealand’s worst events have struck in recent decades, the results showed the three most extreme meteorological droughts in the instrumental record all occurred before 1950.
Forgotten big drys
The most widespread and intense drought began in winter 1914 and lasted until at least February 1915. Most weather stations recorded their worst rainfall deficits on record between July and October, with severe shortages continuing across much of the North Island and eastern South Island through summer.
Nationally, no other eight-month period compares. More than half of all stations recorded one of their five driest periods on record, while the following July-to-February period ranked second – pointing to an extraordinary multi-year drought sequence.
New Zealand has experienced similar late-winter drought onset conditions more recently – most notably in 1993, when Auckland’s reservoirs fell to about one-third of capacity during the city’s water crisis. But a drought on the scale of 1914–15 would likely have produced far more severe impacts.
Looking specifically at summer droughts, November 1907 to February 1908 produced the most widespread extreme rainfall deficits in the historical record.
Many South Island stations recorded their driest conditions on record, and more than twice as many stations recorded extreme deficits compared with the next most severe summer drought in 1945/46.
That 1945–46 drought also stands out in the north and east of the North Island, where many stations recorded their worst rainfall deficits on record. Rainfall shortages in these regions were around 22% greater than during the better-remembered 2012–13 drought.
An underestimated risk
The gap between recent drought experience and these earlier historical extremes is striking – and highlights the importance of looking beyond just the past few decades.
Droughts far more severe than those experienced in recent memory already exist within New Zealand’s climate history.
Yet many modern risk assessments still rely heavily on relatively recent events, potentially underestimating the true scale of drought variability the country is capable of experiencing.
Climate change adds another layer of risk, with rising temperatures expected to further parch soils and increase evaporation in prolonged dry spells, worsening the impacts.
All of this means that recent droughts may no longer provide a reliable guide for what is to come.
A warming climate could push New Zealand into drought conditions beyond anything experienced in living memory – something future planning and risk assessments will need to urgently account for.
Related content
We have lots of resources related to how weather is changing and becoming more extreme due to climate warming.
Climate change resources – planning pathways provides pedagogical advice and links to the New Zealand Curriculum. It includes an interactive planner that groups Hub resources into key science and teaching concepts.
Understanding the basics of climate change – in this recorded webinar Associate Professor Chris Eames explains the key science ideas we need to understand in order to teach climate change effectively.
The article Evidence of climate change in Aotearoa notes further examples of extreme weather events.
For a farming perspective see Dairy farming and climate change – a context for learning – it provides curriculum links, te ao Māori perspectives and an interactive planning pathway.
To view all of our climate change resources, visit the Climate change topic – use the filters to see resources with a Primary level focus.
Activity ideas
Climate change – challenging conversations – this activity uses concept cartoons to encourage conversations about climate change. Concept cartoons put forward a range of viewpoints designed to motivate and engage people and stimulate discussions.
Using soil moisture maps – this activity helps students learn to read and interpret aspects of soil moisture maps and compare data by location and over time.
Useful links
Find out more about some of the research mentioned in this article:
See the Climate Change Commission’s 2026 national climate change risk assessment report.
Impacts of previous droughts in Aotearoa:
Beehive 2009 press release Drought costs NZ $2.8 billion.
Ministry for Primary Industries The 2012-13 drought: an assessment and historical Perspective.
Reserve Bank of New Zealand 2022 Climate Change Risk Assessment for Agricultural Lending.
Different Types of drought measurements, from the National Drought Mitigation Center University of Nebraska-Lincoln.
Read the 2026 research paper that this article is based on, also written by the authors Understanding past record-shattering drought events in New Zealand in the Environmental Research: Climate journal.
Visit NIWA’s Virtual Climate Station Network Virtual Climate Station Network.
Twentieth century droughts and wet periods in Auckland (New Zealand) and their relationship to ENSO, by A. Fowler, K. Adams International Journal of Climatology Vol 24, Issue 15, December 2004.
Storylines of future drought in the face of uncertain rainfall projections: a New Zealand case study, L. Hamish, L J Harringtin, P B Gibson and N Rampal Earth System Dynamics Vol 16, Issue 5, 2025.
Acknowledgements
This article was written by Adam Brown, (PhD Candidate, School of Science, University of Waikato), Dave Frame (Professor of Physics, University of Canterbury) and Luke Harrington (Senior Lecturer in Climate Change, University of Waikato). The article was originally published in The Conversation, 15 May 2026. Read the original article.
The Conversation
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