Impacts on biodiversity, and our cultural, social and economic wellbeing

Ka ora te taiao, ka ora te tāngata

The interconnected nature of the environment means the impacts of our changing climate are cascading through ecosystems, compounding other pressures from human activities including past land use choices, habitat fragmentation and pollution. These compounding pressures are affecting our biodiversity and species ranges and disturbing ecosystem structures, as well as exacerbating the risk of other threats such as invasive species. Heat extremes have driven local extinctions of species, along with mass mortality on land and in the ocean. Biodiversity loss threatens the ability of our ecosystems to absorb carbon and limits their ability to provide protection and resilience against the impacts of climate change.

Climate change is also having widespread effects on humans and our communities and society. In some situations, climate change is increasing risks to our safety and security or exacerbating existing vulnerabilities. Climate-related risks are already affecting the financial system and broader Aotearoa New Zealand economy. Two-thirds of New Zealanders live in areas prone to flooding and rising sea levels. Food insecurity, loss of livelihoods and uncertainty around climate change have ongoing effects on mental health. Changing seasons affect mātauranga Māori (Māori knowledge) and many important Māori practices including the transfer of mātauranga Māori across generations. Māori practices, such as mahinga kai (traditional food gathering practices) and rongoā (healing), need to adapt to the changing availability of species and loss of taonga (treasured) species.

• Climate influences the landscape of Aotearoa: our coasts, river valleys and mountains. It affects the distribution of plants and animals, and the way species interact with one another in their environment, which together form our ecosystems. Changes in our climate are affecting our marine, freshwater and land environments.
• Our oceans are warming, rising and becoming more acidic (see Our marine environment 2022 and Indicators: Ocean acidification and Coastal sea-level rise). Sea surface temperature increased between 0.1 degrees Celsius and 0.2 degrees Celsius per decade across our four oceanic regions between 1981 and 2018 (see Indicator: Sea surface temperature).
• Annual mean coastal sea levels rose faster (relative to land) between 1961 and 2020 than between 1901 and 1960 at all four longer term monitoring sites around Aotearoa (see Indicator: Coastal sea-level rise and Our marine environment 2022).
• Our glaciers are melting. Their volume has decreased by 35 percent and the rate of annual loss increased between 1978 and 2020 (see Indicator: Annual glacier ice volumes).
• Between 1969 and 2019, winter streamflow increased in the western South Island and significantly decreased in the northern North Island; summer streamflow has significantly decreased for most of the North Island. These changes may be influenced by both natural climate variations and anthropogenic climate change (Queen et al, 2023).
• Climate change exacerbates some land degradation processes, such as landslides and erosion, which increases sediment reaching downstream, including coastal and marine environments (Neverman et al, 2023; Smith et al, 2023).

• Rising sea surface temperatures can reduce the abundance of marine food or seabirds’ ability to access it. Population declines in seabirds have been attributed to this, such as tarāpunga (red-billed gulls), hoiho (yellow-eyed penguins) and kororā (blue penguin) (Mills et al, 2008; Salinger et al, 2023).
• Changing ocean currents and rising sea levels have led to a loss of nesting sites for various shorebirds, and declining populations of tītī (sooty shearwater or muttonbird) have been observed (Keegan et al, 2022). The quality and health of tītī were noticed to decline substantially in cycles aligned with the El Niño Southern Oscillation (McKechnie et al, 2020; Scott et al, 2008).
• Ocean acidification is changing calcification rates, making it difficult for species such as molluscs, crustaceans and corals to grow and maintain their calcium-based shells and skeletons (Anderson et al, 2022; Law et al, 2018).
• Habitat shift can occur across the wider environment (McGlone & Walker, 2011; Salinger et al, 2019). For example, some stream invertebrate communities are shifting their range towards higher latitudes, in response to climate and environmental changes (Mouton et al, 2020, 2022).
• Some species, already threatened with extinction, are highly vulnerable to climate change, including īnanga (whitebait) and kākahi (freshwater mussel) (Egan et al, 2020).
• Thermal squeeze is a particular risk for species with limited ability to move into new areas such as kiwi, whio (blue duck) and North Island kōkako (Walker et al, 2019).
• Warmer soil poses a problem for some species, including tuatara, which leads to an increase of male offspring, potentially leading to population decline as reproductive output decreases (Mitchell et al, 2006).
• Range expansion of invasive species can put additional pressure on native biodiversity. Rats and mice advance to higher altitudes in mountain areas and prey on species previously out of their reach like pīwauwau (rock wren) (Willkinson & Parsons, 2020).

• Heat extremes can lead to mass mortality and local extinction, favouring the spread of invasive species. The 2017–18 marine heatwave led to significant loss of rimurapa (bull kelp, Durvillaea). At locations where the kelp was completely lost, an invasive, non native kelp took its place. This coincided with a dramatic decrease in kākahi (Awatere et al, 2021; Thomsen et al, 2019).
• Warmer sea temperatures and ocean acidification can intensify kina (sea urchins) overpopulation by affecting the lifecycle, reproduction and recruitment of kina predators, such as kōura (freshwater crayfish) and tāmure (snapper), which are already in decline from overfishing and other human activities (Gee, 2021; Heeringa, 2021).
• Changes in the timing of seasonal events can have large ramifications for the health of ecosystems. The frequency of natural events, such as masting (the intermittent and synchronous production of large seed crops) in forest and alpine environments, has been linked to changes in temperature (Barron et al, 2016; Kelly et al, 2013; Monks et al, 2016). Beech mast can lead to an outbreak of pests, such as rats, mice and stoats, which poses an increased threat to native forest birds and long-tailed bats (King, 1983; O’Donnell et al, 2017).
• Shifts in the timing and severity of frosts, along with a reduction in snowfall, can disrupt plant–insect pollinator interactions, affecting plant species and ecosystem functions (McGlone & Walker, 2011; Renwick et al, 2016). For example, warm temperatures and drought promote excessive honeydew production in mountain beech and kāmahi forests, which can lead to increases in platypus beetle and subsequent damage to mature trees that can transform forest structure (Awatere et al, 2021; Wardle, 1984).
• Droughts can threaten the survival of iconic species such as the critically threatened kōwaro (Canterbury mudfish) (Meijer et al, 2019) and our endemic kiwi, which find it difficult to extract food from hardened soils (Boffa Miskell, 2020). Droughts can also influence carbon cycling (Macinnis-Ng & Schwendenmann, 2015) and cause the death of trees in all types of forest (Wyse et al, 2013, 2018).
• Shifts in the timing of seasons can affect the life cycle of invasive species, leading to impacts on native species. Climate warming causes a change in flowering time of an invasive plant (heather, Calluna vulgaris) in alpine areas, causing an increased overlap with a native species (monoao, Dracophyllum subulatum). This increases competition for pollinators and causes a decline in reproductive output of the native species, potentially leading to its decline (Giejsztowt et al, 2020).
• Habitat loss and climate change interact to exacerbate population declines. For example, brown mudfish (Neochanna apoda) live in tip-up pools created when large trees fall, however, the combined impacts of reduced numbers of large trees due to logging and reduction in water availability due to droughts can cause population decline (Macinnis-Ng et al, 2021).

• The concurrent air–marine heatwaves in 2017–18 and 2021–22 caused migrations of northern warm-water fishes, early harvest of summer fruit, unprecedented levels of bleaching and necrosis of Aotearoa sponges, mass mortality of kororā in the Bay of Plenty and widespread loss of large habitat-forming intertidal southern rimurapa (Bell et al, 2023; Salinger et al, 2019, 2020, 2023; Thomsen et al, 2019; Thomsen & South, 2019). Aquaculture in the Marlborough Sounds was also affected, with a record number of salmon deaths due to warmer sea temperatures.
• Flooding in 2009 reduced a population of the nationally vulnerable scree skinks in the Canterbury high country by 84 percent. It took about eight years for the population to recover naturally (Lettink & Monks, 2019). Floods have also been shown to affect breeding sites of īnanga and bird nesting habitats in braided rivers (Goodman, 2018; Keegan et al, 2022). Floods are also causing a range of problems from erosion and landslides in hill country to further sedimentation of waterways in coastal plains (Neverman et al, 2023; Smith et al, 2023).
• Tara iti (fairy tern) is at risk of losing its breeding habitat to storm surges, because washouts already occur during storm events (DOC, nd). Strong wind and stormy weather events in 2018 wiped out an entire breeding season of kororā on Otata Island (Forest and Bird, 2018). Storms also increase the turbidity of coastal waters, posing challenges for visual foragers like penguins, gannets and shags (Crockett & Kearns, 1975; Powlesland, 1984 as cited in Whitehead et al, 2019).
• Most terrestrial ecosystems in Aotearoa are not adapted to fire (Kitzberger et al, 2016; Tepley et al, 2018). Recovery from fire events is slow and fires can disrupt the natural succession of ecosystems and favour non-native species over native ones. Furthermore, non-native species are often more flammable, increasing potential fire frequency and intensity (Case et al, 2023a; Perry et al, 2014; Richardson et al, 2018).
• Aotearoa forests are an important resource and a foundation of Māori identity (Waitangi Tribunal, 2011). Wildfire is a growing risk to Aotearoa forests, already under pressure from human disturbances and pests and diseases, such as kauri dieback and myrtle rust (Lambert et al, 2018).
• The wetlands remaining in Aotearoa, around 10 percent of pre-human extent (Dymond et al, 2021), are becoming more susceptible to fire under climate change, further endangering unique ecosystems (Scion, 2022).

• The concept of mahinga kai runs much deeper than a ‘food gathering place’. Mahinga kai connects tangata with whenua (people with land), is intergenerational, and is a holistic and integrated value. It extends beyond food resources to encompass the use of many natural resources, including stones and trees used for fire making, tools, pounamu (greenstone), hāngī (earth oven) stones, mud used for dyes, rongoā and flaxes for weaving (Ruru et al, 2022).
• Mahinga kai remains one of the cornerstones of Māori existence and culture. Changes to our marine, terrestrial and freshwater environments due to climate change can have direct implications on the ability to carry out mahinga kai practices, affecting the transmission of mātauranga Māori and highlighting the importance of safeguarding the embedded knowledge within these practices (Awatere et al, 2021; Glavinovic, 2022; Harmsworth & Awatere, 2013; Phillips et al, 2016).
• Mātauranga Māori, as it applies to mahinga kai, is often in depth and localised, meaning Indigenous peoples have been able to put in context the effect of climate change at the local scale (Nursey-Bray et al, 2022).
• Mātauranga Māori has a past, present and future, and this knowledge is used and adapted to suit contemporary challenges such as climate change (Lambert & Mark-Shadbolt, 2021; Mead, 2022).

• The changing climate requires knowledge adaptation to happen faster and so is expected to affect mātauranga Māori. This can affect, and even sever, the connection to certain taonga species in climate-driven environmental contexts (Awatere et al, 2021; Bond et al, 2019; King et al, 2010; Paul et al, 2016; Penny et al, 2007a, 2007b; Warmenhoven et al, 2014).
• Climate-related impacts, such as severe weather events, can cause the loss of many Māori sites of significance, which affects the mātauranga Māori associated to them (King et al, 2007). The names of these sites are important records of the past, some of which indicate risk and environmental change.
• Coastal erosion is a particularly serious threat to sites of significance because it permanently removes sites, erasing all contextual information important for archaeological preservation and investigation. Spatial mapping of sites in at-risk areas indicates locations of regional sensitivity in the North Island around Taranaki, Auckland, Coromandel and northern Hawke’s Bay, and in the South Island around Tasman and parts of Otago and Canterbury (Jones et al, 2023).
• Changes in local climates are causing tohu (environmental indicators) to change. This affects planting, daily decision-making, and activities like resource gathering and hunting (Skipper, 2018). However, understanding and monitoring tohu as they change over time can help to manage and adapt activities sensitive to climate conditions (King et al, 2005).
• Maintaining and rebuilding connections to customary harvesting of food (kai) reconnects people with whenua (land), repo (wetlands) and other ecosystems and supports the transmission of knowledge to future generations (Herse et al, 2021; Waitangi Tribunal, 2011).
• The changing seasons means the environmental signs are changing at a faster rate, which may affect the environmental observations of the maramataka. Mātauranga Māori, such as the maramataka (see Te ao Māori, whakapapa and our connection to atmosphere and climate), enable Māori and Pacific relatives to attune to the movements of the environment and ensure activities essential for survival and wellbeing are conducted at the optimal times (Warbrick et al, 2023).
• Māori communities are not passive victims of climate change and have a legacy of adaptation over centuries. Mātauranga Māori and other processes are being used to help adapt to climate change (Parsons, 2019 as cited in Nursey-Bray et al, 2022) through proven and sustainable methods. These are based on mātauranga Māori methods and values such as active kaitiakitanga (guardianship) (Benson et al, 2020).

• Being able to exercise kaitiakitanga is both an expression and affirmation of rangatiratanga (chieftainship) (Jackson et al, 2017). Without rangatiratanga and the ability to lead on their own environmental matters at place through te ao Māori values, concepts and practices, it would be difficult if not impossible to practise kaitiakitanga (Blair, 2002 as cited in McAllister et al, 2023; Selby et al, 2010).
• The duty and practices to care for te taiao (the environment) are derived from whakapapa (genealogy) and governed by tikanga (customs and protocols), to maintain healthy mauri for current and future generations (see Te ao Māori, whakapapa, and our connection to atmosphere and climate for a definition of mauri) (Makey et al, 2022).
• Indigenous communities are often challenged with histories that complicate their climate change adaptation planning with authorities, such as land alienation and access (Mannakkara et al, 2023; Mead, 2003, p 130). These vulnerabilities are affecting Māori who now live in or near vulnerable locations.
• A changing climate is not new for Māori (Parsons, 2019 as cited in Nursey-Bray et al, 2022). Māori have always been scientists through navigating expansive oceans, applying a detailed regionally specific division of time, and being immersed with the natural rhythms of the environment (Whaanga et al, 2020).
• Māori approaches to wellbeing, are holistic, grounded in the mātauranga Māori, language and tikanga of distinct hapū and whānau. Māori adaptation plans form the basis of Māori resilience and are a potential significant means of Māori-led action on climate change (Awatere et al, 2022).

• Many sectors of our economy rely on natural resources such as water, which depends heavily on rainfall and temperature (Ausseil et al, 2019; MPI, 2021). This includes the agricultural sector, which is particularly vulnerable to the extremes of high and low rainfall and often located on fertile flood plains, making it one of the highest risk sectors in relation to climate change (Arent et al, 2014; Case et al, 2023b; Craig et al, 2021).
• The two major drought events of 2007–08 and 2012–13 have been estimated to have incurred $4.8 billion in costs, including indirect losses, with human influence on climate change accounting for an estimated 15 percent to 20 percent of these costs, about $800 million (Frame et al, 2018, 2020).
• Droughts reduce the availability of water for agricultural production, which can negatively affect the overall economy, along with households, through reduced employment and income (Bell et al, 2021; Nguyen et al, 2022).
• Flooding events have affected dairy farms across Aotearoa, including in the lower South Island in February 2020, where farm land and infrastructure was damaged and revenue lost where milk tanker access was not possible (Griffin et al, 2023; Paulik et al, 2021).
• Our changing climate is already affecting the suitability of regions for producing different grape varieties (Ausseil et al, 2021). Ripening and harvest dates are advancing with increased temperatures (Salinger et al, 2019, 2020).
• The Māori economy is particularly vulnerable to climate change because Māori own a large share of assets in the primary sector: 50 percent of the fishing quota, 40 percent of forestry, 30 percent of lamb production, 30 percent of sheep and beef production, 10 percent of dairy production and 10 percent of kiwifruit production (MFAT, 2019).
• Forestry plantations are particularly vulnerable to extreme weather events such as storms, droughts and wildfires (Villamor et al, 2023; Watt et al, 2019).
• The decreasing volumes of ice in our glaciers affects tourism, with challenges such as alpine access and tourist safety (Purdie et al, 2020; Wang & Zhou, 2019). However, the rapidly expanding lake at the Tasman Glacier enables visitors to take boat tours to get close to the calving ice at the glacier edge, with shorter winter freezing allowing a longer tourist season (Carver & Tweed, 2021; Purdie et al, 2020).

• Around 750,000 people and 500,000 buildings, worth more than $145 billion, are near rivers and in coastal areas already exposed to extreme flooding in Aotearoa (MfE, 2023b).
• Culturally important sites and infrastructure, such as marae, urupā (burial grounds) and kainga (settlements), are vulnerable to damage from flooding, erosion and extreme weather (Awatere et al, 2021). Around Aotearoa, 191 marae are within 1km of the coast, and, in the Bay of Plenty alone, 41 urupā are within 1km (Bailey-Winiata, 2021).
• Infrastructure in low-lying and coastal communities is particularly vulnerable to climate change, including stormwater and wastewater networks, which are often located together underground (Kool et al, 2020; PCE, 2015). Impacts of climate change on wastewater networks vary between different locations and communities, but include spills, odour and worsened water quality from uncontrolled discharge and infrastructure damage (Hughes et al, 2021).
• Cyclone Gabrielle is an example of extreme weather that damaged fragile infrastructure, including water, transport, power and communication (Ministerial Inquiry into Land Use in Tairāwhiti and Wairoa, 2023). The wastewater treatment plant in Napier was seriously damaged and unable to operate, meaning untreated sewage was released into the sea (Jones et al, 2023).
• Immediate costs from extreme weather events can be significant, with Cyclone Gabrielle and the Auckland floods estimated damages to be between $9 billion and $14.5 billion (New Zealand Treasury, 2023a).
• Extreme weather events can also cause much economic and social disruption. They can damage homes, infrastructure, crops, and disrupt access to healthcare and essential supplies such as drinking water (Grout et al, 2022; Jones et al, 2023). These have long term health and wellbeing implications for individuals and entire communities (Jones et al 2023).
• A high degree of social connectedness can help offset socioeconomic vulnerability to some extent by increasing adaptive capacity. This is because social capital, in the form of networks, neighbourhood cohesion and trust, can enable community members to act towards shared objectives and help each other overcome hurdles (Bixler et al, 2021).

• Extreme weather events can affect public health by causing disease outbreaks and toxic chemical contamination (Grout et al, 2022). Increases in waterborne diseases due to flooding can cause food insecurity and risks to health (Royal Society Te Apārangi, 2017).
• Extreme climate events have been associated with elevated levels of anxiety, depression and post-traumatic stress disorder. Increased frequency of extreme events can lead to exhaustion and emotional tolls on individuals and communities (Ministerial Inquiry into Land Use in Tairāwhiti and Wairoa, 2023).
• Higher temperatures and heat waves can cause illness and death, can worsen chronic health conditions (EHINZ, 2022; Royal Society Te Apārangi, 2017), have been associated with an increased incidence of assaults (Stevens et al, 2019), and are risks for those who work outdoors (Brown & Bryder, 2023; Royal Society Te Apārangi, 2017).
• Climate change contributes to food insecurity affecting health and wellbeing. Foods related to mahinga kai practices sustain more than physical health, so communities have to adapt food systems as part of a reciprocal relationship (Wehi et al, 2023).
• Climate change impacts are not distributed equally, exacerbating existing socioeconomic and ethnic health inequalities. Some communities, including some Māori, are more vulnerable due to geographical location, age, disability, employment, housing and other socioeconomic factors (Crengle et al, 2022; Gamble et al, 2016; Royal Society Te Apārangi, 2017; Smith et al, 2014).
• Climate anxiety, including feelings of hopelessness and frustration, particularly affects some groups. Young people face an uncertain future, and Pacific communities have connections to small island countries susceptible to climate-induced displacement (Burkett, 2011; Fritze et al, 2008).