Record weather underlines climate change challenge

NIWA records show that this winter was New Zealand’s warmest and wettest on record. In the Far North, we were hit by torrential rains that caused flooding and widespread damage to our road network. The most serious impact will be the indefinite closure of State Highway 1 at Mangamuka Gorge following multiple slips last month.

That stretch of road only reopened in July 2021 after being closed for a year while slips were repaired following a July 2020 storm. The most recent slips are still moving, which has prevented Waka Kotahi engineers from fully investigating the damage and they have been unable to provide a timeline for when the highway will reopen. Their task was not helped by more heavy rain earlier this week.

North Hokianga has also been hit hard after a major slip closed West Coast Road between Panguru and Kohukohu on 19 August. This key route for Panguru and Mitimiti residents had already been restricted to one lane near Waipuna Marae by a slip caused by July’s heavy rains. Like Mangamuka Gorge, the slips on West Coast Road are unstable. Engineers hope to get one lane of the road reopened while they work on permanent repair options. Early estimates of how much these and other road repairs will cost the council have topped $6.5 million. That does not include damage caused by severe weather to other infrastructure, such as parks, reserves, water and wastewater services, and so on.

While we had a drenching in July and August, NIWA records show that Northland has seen worse rainfall in the past. What we did see however, were record winter temperatures. Both Kaitāia and Kerikeri recorded the highest mean winter air temperatures since records began in the mid-1940s. Warmer air holds more moisture, which means more rain. It was the third year in a row that New Zealand winter temperatures have broken records and of the 10 warmest winters recorded, six have occurred since 2013. While the La Niña weather pattern along with warmer than normal sea temperatures have been factors in record rainfall, NIWA says climate change is the key contributor.

That means we can expect to see more severe weather events in years to come, which makes climate change one of our top challenges. In response, we adopted a Climate Change Roadmap in 2020. This is focused on reducing council carbon emissions, helping communities become carbon zero, future proofing our assets, and helping communities adapt to the effects of climate change. Work on how we meet these challenges will begin in earnest with Far North communities in coming months. The Climate Change Roadmap complements work we are undertaking with other Northland councils and tangata whenua through Climate Adaptation Te Tai Tokerau. This has already produced New Zealand’s first region-wide climate adaptation strategy, which will ensure we share knowledge and align climate adaptation work across Northland. This co-operative approach is feeding into a range of resources that communities and individuals can use, such as the natural hazards portal now available on the Northland Regional Council website.