Latest news with #NIWA
RNZ News
21-07-2025
- Science
- RNZ News
Can households really assess their own climate risk?
A flood damaged house just outside Riwaka. Photo: SAMUEL RILLSTONE / RNZ An expert panel has called for consistent, quality information on flood risk to enable people to decide whether to buy, rent or renovate properties. But critical research into how storms are changing with hotter temperatures has been defunded, with one scientist saying New Zealand has retreated from the research right when it's needed the most. Last year, an internationally sought-after team of scientists who specialised in understanding how global climate models applied to New Zealand were made redundant by Earth Sciences NZ, then called NIWA. Then, the $10 million Whakahura programme for studying how extreme events are changing was turned down for further government funding after its initial five year run. One of the scientists behind the project, Canterbury University Professor Dave Frame, says there's still a lot we don't know. He says climate scientists are confident that atmospheric rivers of the type that devastated Auckland, Tai Rāwhiti and the Nelson area are getting 10-20 percent wetter because of climate change. Hotter air carries more moisture, which gets dumped on unlucky victims by storms hitting from the north, straight from the tropics. But when it comes to other storms, for example those hitting Southland or Wellington from the south, Frame says it's more complex, with westerlies and other factors also coming into play. "Our community tend to be a little more cautious about those extreme rain events from the south," he says. "But the funding for extreme event research has dried up almost entirely," he says. "Really we've ground to a halt on a lot of climate modelling and extreme event research, right when there is a clear and present need for this. "We're getting hammered by extreme events, they are the sharp end of climate change, and we are actually retreating from our ability to answer these kinds of questions." The expert panel report says households urgently need better information, showing the expected frequency and severity of floods, and including local terrain and features such as stop banks. Its chair, Matt Whineray, says this is the single most important step in preparing for what the panel says should be an end to property buyouts at market value after floods. He says better data won't just inform potential purchasers or renters, but will also help owners lower their risk by raising floor levels and electrical wiring, changing floor coverings and the like. "That's the most fundamental bit, before everybody leaps to how are you going to transition to a different approach of sharing costs after the event, the most fundament bit is that people understand and there's an agreement on how you update that, how people get hold of that information." The report was criticised for recommending moving towards a system where people did not expect to to be compensated for the value of their property if it became uninhabitable - though Whineray clarified this week that they weren't saying people should get no financial assistance helping them recover or relocate. Foxhill resident Graeme Burbidge diverts water to protect his property as heavy rain hits the Tasman district, 11 July 2025. Photo: RNZ/Samuel Rillstone Sarah-Jayne McCurrach, head of risk reduction at the Natural Hazards Commission, says an existing natural hazards platform lets people search for past claims for earthquake and flood damage on a property. "You can go in, there is a map and it will give you a little green dot if a property has had a claim on it." The commission is also running a pilot with the Bay of Plenty region to include information from council natural hazard maps on the platform. But McCurrach says councils vary hugely in their resources and many need help modelling flood risk. "We've got a national flood model in the making, we've got lots of data, and in some areas it's been proven to be accurate. We've had flood modeling done, we've seen Cyclone Gabrielle occur, and it's flooded where we thought it would flood. So in some places it is very well modelled and in others it's not." Frame says for many places it will be difficult to model climate impacts down to the post code level - though in other areas the flood risk is pretty well-known. The chair of a previous report to the government, Victoria University's Jonathan Boston, says it's unrealistic to expect people to manage their own risks, when they are uncertain, and growing. "We can't tell somebody today, that your house will be safe for the next 100 years, regardless of where it is," he says. Better information - when it arrives - is expected to impact property prices, though previous studies suggest that buyers have short memories - and that values aren't strongly affected by hazard maps. Boston says irrational market behaviour and herd mentality mean there may be an abrupt correction at some point, with potentially severe consequences for whoever holds the title at that time. Environment officials are working on how make better data available, and working up options on how and whether to offer payments to those who can't sell as a result.
Scoop
19-07-2025
- Science
- Scoop
‘Birthplace Of The Nation' Threatened By Climate Change
Article – RNZ One of New Zealand's oldest archaeological sites is at risk of rising sea levels, according to a new study. , Māori issues reporter The Wairau Bar, or Te Pokohiwi o Kupe in Marlborough, one of the oldest and most significant archaeological sites in New Zealand, is at risk of being flooded by rising sea levels, according to a new study. One of the study's co-authors Corey Hebberd, a descendant of local iwi Rangitāne o Wairau, said the site is important not only for Rangitāne, but for all of Aotearoa. 'Te Pokohiwi o Kupe is one of the earliest known human settlement sites in Aotearoa, it dates back to at least 1250. We regard it as the birthplace of the nation it was a landing site for some of our first settlers,' Hebberd said. 'The site itself holds a range of artefacts but also more importantly koiwi tangata, so ancestral remains, and for Rangitāne o Wairau it's a sacred wāhi tapu.' As New Zealand was one of the last places in the world to be settled, Te Pokohiwi o Kupe has a worldwide significance as the landing sight of some of those first settlers, he said. 'It tells a story that's important to us as Rangitāne, but also an important story for Aotearoa, but we think internationally as well,' Hebberd said. The Wairau Bar sits at the mouth of the Wairau River with the sea on one side and a lagoon on the other, leaving it susceptible to erosion on both sides, Hebberd said. Rangitāne worked in collaboration with NIWA to model flooding impacts in a one in 100 year storm event, he said. 'The current modelling shows that the site could be potentially susceptible to a one in 100 event and be 20 percent inundated, but, obviously, we know that's going to get worse as sea level rise takes place,' Hebberd said. 'We're expecting that around the 2050s, sea level will have risen by another half a meter, and when we start getting to that point those storm events start to inundate the site closer to 50 percent.' Even more concerning, as the sea level approaches a one meter sea level rise, which modelling shows will happen sometime between 2070 and 2130, approximately 75 percent of the site could be at risk, he said. 'For me, sometimes these threats, the talk of sea level rise and the talk of the storm impacts, it feels so far away, but we're actually starting to see it now,' Hebberd said. 'When we talk about a one meter sea level rise and 75 percent of the site being at risk, that's in my lifetime and that places a real burden and sense of responsibility on my generation.' We have a responsibility to make sure that the stories and the richness of the site isn't lost, he said. Recent heavy rains in the Nelson Tasman region have had a negative effect on the site, although it has escaped any major damage. But Hebberd said each major flooding event leads to further erosion. Protecting the most vulnerable parts of Te Pokohiwi o Kupe from storm events could involve soft engineering, he said. For example, by adding native plants to the bar to bind the soil together and prevent erosion. 'It's a really good opportunity for us to turn our minds to the policy and planning settings that we work within both locally and nationally,' Hebberd said. 'I mean this site is one of many, not only in our rohe, but nationally, that will be exposed to weather events and so we need to start thinking about how we take care of and protect them.' Hebberd said the collaboration between NIWA and Rangitāne weaved together mātauranga Māori and science. 'Our whānau were really supportive of the work that we did, our whānau were engaged throughout the research project, including contributing interviews, spending time with the research team around their experience of previous flooding events in the area.'
RNZ News
17-07-2025
- Science
- RNZ News
'Birthplace of the nation' threatened by climate change
Looking north across the Wairau Bar. Photo: RNZ / Samantha Gee The Wairau Bar, or Te Pokohiwi o Kupe in Marlborough, one of the oldest and most significant archaeological sites in New Zealand, is at risk of being flooded by rising sea levels, according to a new study. One of the study's co-authors Corey Hebberd, a descendant of local iwi Rangitāne o Wairau, said the site is important not only for Rangitāne, but for all of Aotearoa. "Te Pokohiwi o Kupe is one of the earliest known human settlement sites in Aotearoa, it dates back to at least 1250. We regard it as the birthplace of the nation it was a landing site for some of our first settlers," Hebberd said. "The site itself holds a range of artefacts but also more importantly koiwi tangata, so ancestral remains, and for Rangitāne o Wairau it's a sacred wāhi tapu." As New Zealand was one of the last places in the world to be settled, Te Pokohiwi o Kupe has a worldwide significance as the landing sight of some of those first settlers, he said. "It tells a story that's important to us as Rangitāne, but also an important story for Aotearoa, but we think internationally as well," Hebberd said. The Wairau Bar sits at the mouth of the Wairau River with the sea on one side and a lagoon on the other, leaving it susceptible to erosion on both sides, Hebberd said. Rangitāne worked in collaboration with NIWA to model flooding impacts in a one in 100 year storm event, he said. "The current modelling shows that the site could be potentially susceptible to a one in 100 event and be 20 percent inundated, but, obviously, we know that's going to get worse as sea level rise takes place," Hebberd said. "We're expecting that around the 2050s, sea level will have risen by another half a meter, and when we start getting to that point those storm events start to inundate the site closer to 50 percent." Even more concerning, as the sea level approaches a one meter sea level rise, which modelling shows will happen sometime between 2070 and 2130, approximately 75 percent of the site could be at risk, he said. "For me, sometimes these threats, the talk of sea level rise and the talk of the storm impacts, it feels so far away, but we're actually starting to see it now," Hebberd said. "When we talk about a one meter sea level rise and 75 percent of the site being at risk, that's in my lifetime and that places a real burden and sense of responsibility on my generation." We have a responsibility to make sure that the stories and the richness of the site isn't lost, he said. Photo: RNZ / Samuel Rillstone Recent heavy rains in the Nelson Tasman region have had a negative effect on the site, although it has escaped any major damage. But Hebberd said each major flooding event leads to further erosion. Protecting the most vulnerable parts of Te Pokohiwi o Kupe from storm events could involve soft engineering, he said. For example, by adding native plants to the bar to bind the soil together and prevent erosion. "It's a really good opportunity for us to turn our minds to the policy and planning settings that we work within both locally and nationally," Hebberd said. "I mean this site is one of many, not only in our rohe, but nationally, that will be exposed to weather events and so we need to start thinking about how we take care of and protect them." Hebberd said the collaboration between NIWA and Rangitāne weaved together mātauranga Māori and science. "Our whānau were really supportive of the work that we did, our whānau were engaged throughout the research project, including contributing interviews, spending time with the research team around their experience of previous flooding events in the area." Sign up for Ngā Pitopito Kōrero , a daily newsletter curated by our editors and delivered straight to your inbox every weekday.
RNZ News
14-07-2025
- Climate
- RNZ News
Flash floods - How do they happen and do we get them in New Zealand?
People look on as law enforcement and volunteers continue to search for missing people near Camp Mystic, Texas on 5 July 2025. At least 130 people have died and dozens are missing after the flash floods. Photo: Ronaldo Schemidt / AFP Explainer - Hundreds are dead or missing in Texas flash floods. The Tasman District has been hit hard in recent weeks. What is flash flooding, and why is it so hard to predict? The terrible power of water has been in the news lately, between the Tasman region's massive "100-year floods" and the deadly flash flooding in Texas that has claimed 130 lives and left nearly 200 people missing. There's been a lot of talk about "flash floods" and the carnage they can cause, but how is a flash flood different from more common flooding caused by heavy rain? Here's what you need to know. A flash flood is a flood - just far faster, and often, deadlier than other flooding, which typically comes with just a bit more warning. "The main difference between flash flood and regular flooding is speed on onset of flood," said NIWA hydrologist Shailesh Singh. "As [in] the word flash, flash flood onset very fast can happen within few minutes to few hours as compared to regular flood [that] occurs gradually." Location matters, as being close to a river, creek or in a narrow canyon can create more of a risk. "There are lots of different factors that can lead to flash flooding, including elements such as the topography of an area and how a river is flowing," said MetService meteorologist John Law. In Texas, the devastating flash flood that swept through the hill country along the Guadalupe River on the weekend of 4 July left hundreds of people dead or missing, many of them children. The river rose 26 feet - nearly 8 metres - in mere minutes, stunning residents. Watch: Timelapse video shows Texas river rising Rivers flooding can create staggering death tolls. For instance, the flooding of the Yellow River (Huang-He) in China in 1887 is estimated to have killed between one and two million people. Ngātīmoti resident Shiloh Hobi on 13 July, 2025, after slash came through his property. Photo: RNZ/Samuel Rillstone The recent flooding in the Tasman District was catastrophic and has caused immense damage, but most of it hasn't met the definition of a flash flood. "It was forecasted a few days ahead, which doesn't really fit the sudden nature of a flash flood," said MetService Principal Scientist for Groundwater & Hydrological Modelling Channa Rajanayaka. Of course, isolated incidents of flash flooding could still be seen in Tasman. Shiloh Hobi saw what was once a small creek at the back of his Motueka Valley property explode into a massive flood of water, silt and forestry slash in Friday's rain. "It's so wild when a flood like this comes and so many logs together - it's absolutely unpredictable," he told RNZ. Flash floods are "short but can be really destructive," Rajanayaka said. "Regular floods tend to build up more slowly and they usually give you more warning." In Texas, the Guadalupe River has been prone to flash flooding for many years, a long and narrow river basin where "the steep topography produces rapidly rising river stages during storm periods, leaving residents with little warning time," the US Geological Survey says . There have been multiple fatal floods there in the past, too. There have also been questions about the locations of homes within flood zones and close to the river in Texas, including a camp where dozens of children were staying . The deadly floods also came in the middle of the night, catching many off guard. But there is also a vulnerability in New Zealand, "especially in steep hill country or in cities/towns where water can build up quickly", Rajanayaka said. Historically, several deadly events in Aotearoa have been attributed to flash floods, such as when 21 people were killed in the Kōpuawhara flash flood of 1938 which struck workers at a railway building site. Two people are guided across dangerous floodwaters in Tasman on Friday 11 July, 2025, by members from Fire and Emergency NZ's specialist water response teams from Christchurch and Nelson, using long poles to test what lies under the water. Photo: Supplied/ Fire and Emergency NZ New Zealand is particularly prone to flooding, with 425,000 km of rivers and streams, according to the Ministry for the Environment. "In terms of meteorology, understanding the intensity and location of rainfall is key to forecasting areas likely to be impacted by flooding," Law said. He said Severe Weather Warnings highlight areas that are likely to see heavy rainfall and these are used by hydrologists to model how rivers and streams will respond. "In addition to the broad areas of rainfall covered by Heavy Rain Warnings, some of our heaviest rainfall can be in the form of small scale but intense thunderstorms and downpours of rain," he said. "These can produce extremely large amounts of rainfall in a very short space of time, leading to localised flooding." A sample of NIWA river flow forecasting system video research. Photo: Screenshot / NIWA Pinpointing exactly where downpours will develop is a harder forecast, Law said. "Severe Thunderstorm Watches are issued to highlight areas where all the ingredients come together and there is a potential for intense rainfall. "Once a severe thunderstorm has developed, it is tracked using radar and Severe Thunderstorm Warnings are issued which show the predicted movement of the storm over the next 60 minutes." A variety of local government authority hydrological forecasting systems are in place across the country. NIWA is developing a national river flow forecasting system as well, with a model prototype that has been put forth as a case study . A painted broken heart is seen near Camp Mystic along the Guadalupe River in Hunt, Texas, on 8 July 2025, after severe flash flooding over the July 4 holiday weekend. Photo: RONALDO SCHEMIDT / AFP For flash flood and flood risks in general it's good to be prepared. "We don't have a separate set of advice for flash flooding, as it is essentially flooding that happens rapidly," said National Emergency Management Agency communications manager Anthony Frith. "The general advice stands; pay very close attention to weather watches and warnings, and - super important - evacuate to higher ground immediately if you encounter rising floodwaters. "Don't wait for an official warning for a phone alert. Or as our campaign slogan says - get the flood out ." NEMA's Civil Defence flood preparation website warns people to find out what the flood risk is in their area. "Practice your emergency plan and your evacuation route to higher ground," it recommends. "Take measures to reduce potential flood damage and make sure your insurance policy covers you for flood damage." NIWA's Singh said property owners can mitigate some possible impacts as well. "Maintaining vegetation cover and reducing soil erosion on hill slopes to reduce runoff can be adopted to minimise the risk." Another big risk during flooding is attempting to drive through flood waters. Even a relatively small amount of water can damage cars or strand them. In America, it's been reported by government agencies that over half of all flood-related drownings occur when a vehicle is driven into hazardous flood water. Flooding caused by a flash flood at the Guadalupe River in Kerrville, Texas. Photo: RONALDO SCHEMIDT / AFP Flash floods can move incredibly fast, and even the best planning can be caught off guard. There have been questions about the response in Texas by emergency services, and whether emergency alerts were issued in time . Texas' Republican governor has pushed back at any attempts to cast blame, while Homeland Security Secretary Kristi Noem has denied reports recent policy changes under the Trump administration have slowed disaster aid . In New Zealand, the emergency mobile alert system can be activated during extreme weather. Mobile alerts were issued during the recent flooding in the Nelson region. In the end, the terrible truth about flash floods is that they are inherently difficult to see coming. "It's pretty hard to forecast exactly, because it happens so fast and in such small areas," NIWA's Rajanayaka said. "The scale makes it tough. But better warning systems, smarter land use, and good drainage can definitely help reduce the risk." Sign up for Ngā Pitopito Kōrero , a daily newsletter curated by our editors and delivered straight to your inbox every weekday.
1News
10-07-2025
- Science
- 1News
Threat to one of NZ's oldest burial sites the 'canary in the coal mine'
One of New Zealand's earliest and most significant archaeological sites is at risk of rising sea levels driven by climate change, according to a new study. Referred to as the birthplace of the nation, the Wairau Bar, or Te Pokohiwi o Kupe, in the Marlborough region is widely regarded as the landing site of the first settlers from Polynesia. One of the study's authors Corey Hebberd of local Rangitāne o Wairau iwi told Breakfast that the site had been subject to science and research in the 1940s, despite protest from local iwi. He said it resulted in the remains of 60 tupuna and their associated taonga being uplifted 'in the name of research' by the then Dominion Museum. Only in relatively recent times were they repatriated and returned to the Wairau Bar for burial. 'So it's a significant site,' said Hebberd, 'not just for us as Rangitāne, not just for us as Māori, but for the country as that place of first settlement that links us to Hawaiki and serves as our first place of settlement". ADVERTISEMENT Now there are concerns around the impact of climate change on the site. Hebberd referred to recent weather events that have caused severe flooding to the top of the South Island. 'We seem to be having 1 in 100-year storm events every year. The site as we've found through the research project is susceptible to 1 in 100-year flooding events, and by that we mean that 20% of the site could be impacted, meaning disturbing of middens, of artefacts, of burial sites.' The more worrying concern, he said, is the threat from rising sea levels. The research suggests that approximately 54% of heritage land becomes affected by a 100-year storm inundation event with a 0.5 metre increase in sea level – likely to be reached between 2045 and 2060. The modelling also suggests that a 1 metre sea level rise is likely to be reached between 2070 and 2130, where approximately 75% of heritage land then becomes compromised by a 100-year storm inundation event. Alongside whānau, the iwi have been working closely with NIWA – which has newly merged with GNS Science to become Earth Sciences New Zealand – for the past couple of years. ADVERTISEMENT 'We've been modelling former storm events, we've been creating vulnerability maps, but we've also been engaging with our whānau to understand in their lifetime some of the memories that they have of the flooding impacts of the flooding events.' From their research they are developing a model that talks to the cultural impact the events have beyond the coastal and environmental. Corey Hebberd (Source: Breakfast) Hebberd said in some respects their findings have been alarming. 'You sometimes think that these things might not happen in your lifetime but, you know, the years that I've just rattled off, I'm a child of the 90s, those will happen in my lifetime and they become a real responsibility for my generation and generations to come.' He hopes the model they are working on will lead to further exploration and development of tools that can help mitigate the threat to the site. 'Like what are the soft engineering features that we can start to do, are there things that could slow down erosion, are there protections that we can put in place, what research can we do in the meantime to understand the area' ADVERTISEMENT 'There's also the opportunity for us to work together at a national level at a local level to put more protections in place. To raise profiles of sites like this to come up with national planning strategies that address these sites, because they are vulnerable and they are at risk of being lost and they tell so much story, and they tell so much about our national identity.' He describes the situation at Te Pokohiwi o Kupe as 'the canary in the coal mine', pointing to other low-lying sites of archaeological, as well as cultural, significance such as marae and urupā. 'What we're hoping here is that this research will help to develop a new tool that can inform policy and decision makers around some of the cultural impacts that this has around identity and so we can work together to come up with ways to minimise and mitigate the impact that these events have.'
