High humidity for Northland this weekend as climate change starts to bite
Reminder, this is a Premium article and requires a subscription to read. A walker takes advantage of the unusual warm weather Northland is having, with energy-sapping high humidity due this weekend. Photo / Michael Cunningham Northlanders will need to turn on the fans in an attempt to beat the heat for the next week as a tropical weather pattern brings high humidity and sticky days and nights to the region. Humidity levels are expected at between 80 per cent and 100 per cent tonight and tomorrow, and while the humidity will likely be below that for the start of next week, it's likely to be just as high again on Wednesday and Thursday nights. And to make things worse, Niwa meteorologist Ben Noll said there could also be thunderstorms and rain across the region too. Noll said the high humidity for Northland was very unusual at this time of year, with levels normally only getting that high in December and January. The phenomenon is partly caused by climate change, which, he said, will likely lead to more frequent unseasonal weather in the future. He said tonight and tomorrow night will be when the humidity should be at its peak - up to 100 per cent humidity - and Northlanders will be feeling hot and sticky in the muggy weather. Overnight lows across Northland will be around 17C and daily highs in the early to mid 20s. "So it's going to be very toasty overnight up there, and that will be affected by how much cloud cover there is - clouds could bring the temperatures down, but not the humidity," Noll said. The sticky warmth is due to a moist airflow coming from Vanuatu and Fiji and he said it might feel like Northland has become one of those tropical islands with the weather it's likely to experience. "It's bringing all this tropical weather that will make things very sticky in Northland. That humidity is what you would expect on a tropical island rather than in Northland in October. It's very unusual to have this level of humidity this early in spring and that mugginess might seem even worse as it's much earlier than people would expect. "You may have to turn the air conditioning on overnight this weekend or get the fans out of the cupboard to help keep cool. It's [humidity] much earlier than normal for you and it will be felt by people. One place to escape it might be the beach. Northland has so many great beaches and the temperatures will be a bit cooler there than inland so that's an option, but people will also need to be aware of the sun." Noll said there'll be some relief, with humidity levels dropping - though still higher than normal for the time of year - from Monday to Wednesday. "Then it's likely to be back up to those levels (80-100 per cent) on Wednesday and Thursday nights and maybe into Friday." Compounding this weekend's humidity was that sea temperatures around Northland were also higher than normal - up 1C on the usual - and that could make the situation even worse. "Sea temperatures are also unusually warm in Northland and warmer seas contribute to warmer land temperatures, which then can contribute to the seas getting even warmer, and that can lift the humidity further." Noll said as climate change progresses, Northland will see increasing frequency of abnormally warm temperatures, with such high and early humidity becoming more common. "The extreme weather events will become more common with climate change. And while we can't link all of this {week's high humidity levels] to a warming planet, it certainly is a big contributor, and it's certainly part of that bigger [climate change] picture." Noll said it had been a pretty dry October so far, and this weekend will see some decent downpours for different regions. In the west and north, the humidity might peak at relative values of 80 to 100 per cent. He saw the better metric as dew point: that's the temperature at which, if cooled, water vapour from the air would condense on to a surface such as grass. That required 100 per cent relative humidity and occurred when air temperature equalled the dew point. We really began feeling clammy when the air was both warm enough to make us sweat, but carried enough water vapour to interfere with the process. "We could consider that a dew point of 13C would mean moderate humidity, and 19C high humidity," Noll said. One of the wettest and warmest July months ever recorded in Northland has a climate scientist warning the region to get ready for "a new normal" of winter downpours coupled with summer droughts. Niwa data showed it was overall New Zealand's wettest and fourth-warmest July on record, with five significant weather events between July 11 and 31 giving the nation a good soaking. That will come as no surprise to Northland farmers, firefighters and road workers, who had to deal with sodden pastures, flooded highways, downed trees and roads wiped out by slips. Climate change is here and Niwa climate scientist Nava Fedaeff said Northland was already experiencing climate change. "It's not necessarily something off in the future. We're already living in it," she said. Overall New Zealand recorded its warmest-ever winter in 2020, a record that was promptly broken in 2021. Fedaeff expected the warming trend would continue, though that didn't mean Northlanders would never again experience a cold winter. Predicting future rainfall was more complicated. Higher temperatures meant the air was able to hold more moisture, which meant more rain. However, in Northland's case, even if total rainfall remained roughly the same, it was likely to be distributed unevenly throughout the year with more flooding in winter and long dry spells in summer. That "new normal" would make planning and water management difficult for the region's vital primary sector. This year was also likely to bring the third La Nina weather pattern in a row, with long periods of dry, settled weather this coming summer, only broken up by occasional tropical storms - although the rain they brought could bypass Northland, as happened last summer. It wasn't all bad news, however, with July's rain helping recharge groundwater depleted by a series of summer droughts. "There are also new opportunities for Northland because the climate could become more favourable to new industries and crops, as long as people take climate change into account when they're making long-term decisions," Fedaeff said. Niwa said 2021 was the country's hottest year in more than a century of records, with a mean land surface temperature of 13.56C - or just shy of 1C above the 1981-2010 average. Due to marine heatwave conditions, the institute is predicting periods of excessive humidity and hot temperatures are more likely. According to Niwa, the impacts of climate change on New Zealand include not only challenges but "opportunities to do things differently to ensure a positive future". "As the country warms, high-value crops that are normally grown in warmer climates, like avocados, may be able to be grown in new areas of the country," the institute said. A new Department of Conservation (DoC) report predicts climate change could have a major impact on some of New Zealand's marine mammals. Co-authored by Jim Roberts, Anemone Consultants, and Hannah Hendriks, DoC's marine technical advisor, the research paper examines climate change in relation to marine mammals' habitat, distribution, food sources and predators. It looked at how specific climate change hazards, such as increasing sea temperatures, rising sea levels, changes in ocean circulation and effects on prey species, would impact marine mammals around New Zealand. The report identifies changes in food supply as the biggest threat to marine mammals in New Zealand waters. "This is likely to impact populations including kekeno/New Zealand fur seal[s] in the Westland region and blue whales foraging at the South Taranaki Bight," Hendriks said. "Maui dolphins also appear vulnerable, based on their location at the warm end of the species' range and an apparent low availability of prey species." Projected changes to the New Zealand environment include sea surface temperatures rising more than 3C, changes in atmospheric climate and oceanographic circulation, rising sea levels, and widespread ocean acidification. "As a result, it is possible species normally living in warmer subtropical waters like the dense-beaked whale, dwarf sperm whale, pan-tropical spotted dolphin, short-finned pilot whale and pygmy killer whale, will become more common around New Zealand, and potentially outcompeting some of the marine mammals we currently see," she said. "Similarly, species that live in cooler sub-Antarctic waters could become sparser around New Zealand as they move south." The review shows changes to the environment won't be felt equally in all parts of New Zealand. With climate change set to affect almost every aspect of life in Northland, the region's crop, fruit and vegetable growers will have to examine what they grow, and how to deal with the effects of a warming environment. More extreme weather events and warmer temperatures mean maize growers will need to continually refine and adapt their production system to be more resilient or face the prospect of falling yields, Foundation for Arable Research (Far) senior researcher maize David Densley said. Maize growers are facing the headwinds of increasing cost of production, extreme weather events and environmental considerations, Densley, who led a series of Far maize workshops throughout the North Island and in Canterbury, said. Weather data to determine evapotranspiration (ET) rates during the 2021-22 maize production season showed the total ET was 469mm, compared with the 20-year average of 417mm. This meant crops needed 52mm more moisture to achieve the same yield. During the critical grain fill period, the estimated maize yield loss when drought stress persists for four or more consecutive days is around 3 to 9 per cent yield loss per day of stress. Weather data also showed that soil temperatures in October are not much higher than the long-term average. "So, if growers' strategy is to plant earlier to beat soil moisture stress during flowering, the October soil temperatures aren't helping much," Densley said. Northland farmer Hugh Rose said more varieties of tropical fruit will be grown in Northland as climate change intensifies, meaning some of our traditional crops will have to be abandoned as it will be too hot for them to grow. While he grows mainly bananas at his tropical paradise in Maungatapere, 15 minutes from Whangarei, called Land of the Lotus, he also has a "good collection" of lotus plants which he sells to collectors all over the country. "They're popular with Asians and Indians and people with large ponds," he said. "The seeds taste like peanuts, and the seedpods can be used in stir fries. The other nice thing is that they sterilise mosquitoes. They put an enzyme into the water that sterilises them. They're a multipurpose plant." Rose has more than 40 banana varieties growing on his 25ha property. He also grows pineapple, paw paw, papaya, and babaco (also known as champagne fruit), along with capuli cherries, dragon fruit, sugar cane, mangos, lychee, Japanese raisins, and the jaboticaba (or Brazilian grape tree). "It's an electric sub-tropical batch," Rose said. "You get a bug, and you keep on going." Rose's journey growing tropical and sub-tropical fruit started in 2002 after being inspired by Owen Schafli, who grows pineapples commercially with his wife Linda in Parua Bay. Schafli started with 400 plants and now has more than 30,000 thriving on their property. The couple also grows bananas, papayas, passionfruit, sugar cane, dragon fruit and even coffee. We all know about climate change. Heatwaves, drought, wildfires, flooding, water shortage and sea level rise - we see it all around us and the data tell us it's becoming more severe, and more frequent. Our world is warming and it's disrupting the 'business as usual' way we're used to living. Thing is though, when we go to bed at night here in our little corner of the world, most of the time everything looks and feels the same when we wake in the morning. So how relevant is climate change to us here in Northland? Do we need to worry about it and how do we do anything about it? These are questions Northland Regional Council's climate change manager Tom FitzGerald likes to answer. "The days of arguing about whether climate change is real or not are long gone. It's unequivocal. It's happening now and it's our responsibility to be as prepared as we can be, and to do as much as we can to reduce our own impact on the climate. One thing we can do is prepare for it by becoming more adaptable and resilient. That's what I'm interested in helping our communities with." On the back of one of the wettest and warmest winters ever recorded in Northland, FitzGerald said the region will start to witness more serious weather events unfold, whether they be flooding-related or, conversely, drought. For a region such as Northland, with one of the largest coastlines in the country, the interaction between society and the coastal environment is of particular importance. "Northland communities are particularly exposed to climate change with many settlements, town centres, roads and other critical infrastructure sitting on coastal flood plains, exposed to sea level rise and increased flooding." FitzGerald said urgency is paramount when it comes to adapting to climate change. The problem is not just because sea levels are rising, but also because many areas of coastline in New Zealand, including parts of Northland, are actually sinking. "For us, adapting to the impacts of a changing climate is a key focus. We're doing this in places like Kaitaia where the $15 million upgrade to the Awanui river flood scheme has made the system more resilient and able to cope with the predicted larger flooding events we're going to get. We saw this in action with the recent flood event in the Far North. NRC [Northland Regional Council] hydrology team data showed the water flow in the Awanui river looks to be the biggest on record since 1958 when the NRC gauge was installed, in fact as much as 40 per cent bigger. "This kind of work is also happening in Panguru and the Otiria/Moerewa area. By adapting our infrastructure to better cope with increased flood risks we can lower the risk to people and property." FitzGerald said the response to climate change is multi-faceted and has necessitated a joint approach between all four Northland councils and Maori. In April, a regional adaptation strategy was adopted that set a path for greater collaboration, improved understanding and a more comprehensive response to the climate crisis. It's the first regional approach adopted in the country. The recent release of the Government's National Adaptation Plan also reflects an increasing priority on addressing climate change and has reinforced the amount of work needed to be done to future proof our most vulnerable communities. The NRC has its own climate change strategy, Nga Taumata o te Moana, which follows the three pou of the climate change crisis: adaptation, emissions reduction and carbon removal. "Many of the actions prioritised within these documents seek to enable and support tangata whenua to lead climate change action in their rohe for their whanau. I'm also keen to help our coastal and riverside communities choose their own adaptation actions - sooner rather than later. For me, this is about enabling better partnerships, working to empower action on the ground and fulfilling our leadership role," FitzGerald said. One place where this community-led adaptation planning response is being piloted is the low-lying Ruawai-Raupo area in Kaipara. The area, built on former swampland and renowned as the kumara capital of the country, is already susceptible to flooding from both sea and river and will become more vulnerable as climate change bites. Work has already started here and the first community events discussing the problem and talking about possible solutions have taken place. Tips to beat the humidity: 1. Drink lots of water. The amount of water you need to drink every day varies by person, but a good rule of thumb is to drink water with each meal and in between. 2. Eat cool foods like salads and fresh fruit. Eating hot foods when it's hot and humid will raise your body temperature. 3. Take a cool shower or splash water on your pulse points. 4. Cover your pots while cooking. 5. Dry your clothes outside. 6. Use fans. 7. Turn on the air conditioning 8. Temporarily take the plants outside. 9. Clean the drains. 10. Wear looser clothing, especially at night. Reminder, this is a Premium article and requires a subscription to read. A new economic impact report details the effects of repeated closures.