El Niño, the climate phenomenon that has captivated and challenged New Zealand for centuries, is once again in the spotlight. This time, it's not just about warmer ocean temperatures or tropical fish in fishermen's nets; it's about understanding the complex interplay between nature and our own expectations. As we delve into the history of El Niño's impact on New Zealand, one thing becomes clear: it's not just about the weather, but also about the human response to it.
The El Niño Effect: More Than Just Weather
El Niño, as Climate Prescience director Nathaneal Melia explains, is the largest form of natural climate variability in the world. It's a phenomenon that affects the Pacific region significantly, but its impact on New Zealand is often misunderstood. Melia's comparison of El Niño to Zeus, with other climate drivers as minor and demi-gods, highlights the complexity of the situation. New Zealand's distance from the high-impact zone in the tropical Pacific means that El Niño's effects are weaker and less predictable here compared to regions like Indonesia, which frequently suffers from wildfires and droughts.
A History of El Niño in New Zealand
New Zealanders have a tendency to get excited about El Niño events, but as University of Waikato climate scientist Luke Harrington points out, this excitement is often misplaced. The relationship between El Niño and New Zealand's weather is not as strong as we might think. However, modern observations have revealed certain trends that are more likely to occur during a strong El Niño.
1982-83: The Textbook El Niño
One of the most memorable El Niño events in New Zealand's history occurred in 1982-83. James Renwick, now a professor of physical geography at Victoria University, recalls the excitement and anticipation as the MetService issued its first-ever press release about the coming El Niño. The conditions were indeed textbook: drier than normal conditions in the east, wetter than normal conditions in the west, and a westerly flow that generally kept temperatures cool. The farming community struggled with droughts in Hawke's Bay and Gisborne, and the media and public were captivated by the phenomenon.
1991-1994: Cooler Temperatures and Power Crisis
Contrary to popular belief, El Niño doesn't always bring hot summers. The early 1990s El Niño events, though not strong, were back-to-back and coincided with the eruption of Mount Pinatubo in the Philippines. This volcanic eruption created a 'canopy' of debris in the atmosphere, cooling the planet for a couple of years. The winter of 1992 was particularly cold, with lower temperatures leading to less moisture in the air and less rain. This exacerbated the prolonged drought, putting pressure on farming, water supplies, and the hydro lakes. The winter of 1992 also coincided with a power crisis, as El Niño exacerbated the drought.
1997-1998: Drought and Heatwave
The summer of 1997-98 was another textbook El Niño event for New Zealand. Eastern regions were badly affected by drought, with apple growers finding their crops sunburnt and overheated. Some orchardists left nearly half the fruit unpicked, and the costs to agriculture alone were estimated at $425 million (about double that in today's money). Atypical hot temperatures towards the end of the summer put pressure on city populations, leading to increased demand for urban air-conditioning and electricity.
2015-2016: A Missed Opportunity
The 2015-2016 El Niño was forecasted to be severe, but it didn't materialize as expected. While there were some regional impacts, they were not widespread or significant. The typical south-westerly patterns developed at first, but a change to more northerly-quarter winds brought more rain and alleviated fears of El Niño-associated drought. However, this event highlights the unpredictability of El Niño and the importance of risk management for farmers and others whose livelihoods are affected by prolonged dry conditions.
El Niño's Impact: Beyond the Weather
El Niño's impact on New Zealand goes beyond the weather. It's about understanding the complex interplay between nature and human response. As Renwick points out, El Niño events can bring both droughts and cooler temperatures, and they can exacerbate existing challenges, such as power crises and water shortages. The phenomenon also raises questions about our preparedness and resilience in the face of natural climate variability.
Conclusion: Learning from History
As we continue to observe and study El Niño, it's clear that New Zealand has a lot to learn from its history with this climate phenomenon. By understanding the trends and impacts of past events, we can better prepare for the future. As Harrington suggests, not every El Niño brings drought, and not every drought happens in an El Niño year. However, the risk of El Niño-driven drought during a strong event is a critical consideration for farmers and others whose livelihoods are at stake. As we move forward, it's essential to strike a balance between excitement and realism, and to use our historical knowledge to inform our understanding of El Niño's complex and ever-evolving impact on our country.
