Editing IPCC:AR6/WGII/Chapter-11 (section)

=== 11.3.4 Food, Fibre, Ecosystem Products ===

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The food, fibre and ecosystem product sectors are economically important in the region. Agriculture contributes around 4% of New Zealand GDP and 2% of Australian GDP and over 50% of New Zealand’s and 11% of Australia’s exports ( [[#NZ%20Treasury--2016|NZ Treasury, 2016]] ; [[#Jackson--2020|Jackson et al., 2020]] ). Forestry contributes 1% of New Zealand GDP and 0.5% Australian GDP ( [[#NZ%20Treasury--2016|NZ Treasury, 2016]] ; [[#Whittle--2019|Whittle, 2019]] ). With processing and indirect effects, the primary sector of New Zealand contributes 25% of GDP ( [[#Saunders--2016|Saunders et al., 2016]] ). The region has the lowest level of agricultural subsidies across the OECD ( [[#OECD--2017|OECD, 2017]] ) and highly responsive producers to market drivers but limited strategic, longer-term approaches to environmental challenges and adaptation ( [[#Wreford--2019|Wreford et al., 2019]] ). Both countries receive government financial drought assistance ( [[#Pomeroy--2015|Pomeroy, 2015]] ; [[#Downing--2016|Downing et al., 2016]] ).

Impacts resulting from climate change are observed across sectors and the region ( ''high confidence'' ). While more intense changes are observed in Australia, New Zealand is also experiencing impacts, including the economic impacts of drought attributable to climate change (Frame et al. 2020). Overall, modelling indicates that negative impacts will intensify with increased levels of warming in both countries, with declining crop yield and quality, and negative effects on livestock production and forestry. Although benefits are identified, particularly in the short term for New Zealand ( [[#MfE--2020a|MfE, 2020a]] ), an absence of studies that consider the totality of climatic variables, including extremes, moderate the benefits identified from considering only selected variables and systems in isolation.

Incremental adaptation is occurring ( [[#Hochman--2017|Hochman et al., 2017]] ; [[#Hughes--2017|Hughes and Lawson, 2017]] ; [[#Hughes--2021|Hughes and Gooday, 2021]] ). In the longer term, transformative adaptation, including land use change, will be required ( [[#Cradock-Henry--2020a|Cradock-Henry et al., 2020a]] ), both as a result of sectoral adaptations and mitigation ( ''medium confidence'' ) ( [[#Grundy--2016|Grundy et al., 2016]] ). Specific changes are context specific and challenging to project ( [[#Bryan--2016|Bryan et al., 2016]] ). Future adaptive capacity may be limited by declining institutional and community capacity resulting from high debt, unavailability of insurance, increasing regulatory requirements and funding mechanisms that lock in ongoing exposure to climate risk, creating mental health impacts ( [[#Rickards--2014|Rickards et al., 2014]] ; [[#Wiseman--2016|Wiseman and Bardsley, 2016]] ; [[#McNamara--2017|McNamara and Buggy, 2017]] ; [[#McNamara--2017|McNamara et al., 2017]] ; [[#Moyle--2017|Moyle et al., 2017]] ; [[#Robinson--2018|Robinson et al., 2018]] ; [[#Ma--2020|Ma et al., 2020]] ; [[#Yazd--2020|Yazd et al., 2020]] ).

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==== 11.3.4.1 Field Crops and Horticulture ====

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===== 11.3.4.1.1 Observed impacts =====

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Drought, heat and frost in recent decades have shown the vulnerability of Australian field crops and horticulture to climate change ( [[#Cai--2014|Cai et al., 2014]] ; [[#Howden--2014|Howden et al., 2014]] ; [[#CSIRO%20and%20BOM--2015|CSIRO and BOM, 2015]] ; [[#Lobell--2015|Lobell et al., 2015]] ; [[#Hughes--2017|Hughes and Lawson, 2017]] ; [[#King--2017|King et al., 2017]] ; [[#Webb--2017|Webb et al., 2017]] ; [[#Harris--2020|Harris et al., 2020]] ) as recognised by policymakers ( [[#CoA--2019a|CoA, 2019a]] ) ( ''high confidence'' ). Northern Australia’s agricultural output losses are on average 19% each year due to drought ( [[#Thi%20Tran--2016|Thi Tran et al., 2016]] ). In southern Australia, the frequency of frost has been relatively unchanged since the 1980s ( [[#Dittus--2014|Dittus et al., 2014]] ; [[#Pepler--2018|Pepler et al., 2018]] ; [[#BoM%20and%20CSIRO--2020|BoM and]] [[#CSIRO--2020|CSIRO, 2020]] ). Drier winters have increased the irrigation requirement for wine grapes ( [[#Bonada--2020|Bonada et al., 2020]] ), while smoke from the 2019/20 fires, which occurred early in the season, caused significant taint damage ( [[#Jiang--2021|Jiang et al., 2021]] ). In New Zealand, reduced winter chill has a compounded impact on the kiwifruit industry, resulting in early harvest and increased energy demand for refrigeration and port access problems ( [[#Cradock-Henry--2019|Cradock-Henry et al., 2019]] ) (11.5).

Across all types of agriculture, drought and its physical flow-on effects have caused financial and emotional disruption and stress in farm households and communities ( [[#Austin--2018|Austin et al., 2018]] ; [[#Bryant--2018|Bryant and Garnham, 2018]] ; [[#Yazd--2019|Yazd et al., 2019]] ) (11.3.6). Severe and uncertain climate conditions are statistically associated with increases in farmer suicide ( [[#Crnek-Georgeson--2017|Crnek-Georgeson et al., 2017]] ; [[#Perceval--2019|Perceval et al., 2019]] ). Rural women often carry extra stress and responsibilities, including increased unpaid and paid work and emotional load ( [[#Whittenbury--2013|Whittenbury, 2013]] ; [[#Hanigan--2018|Hanigan et al., 2018]] ; [[#Rich--2018|Rich et al., 2018]] ).

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===== 11.3.4.1.2 Projected impacts =====

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Australian crop yields are projected to decline due to hotter and drier conditions, including intense heat spikes ( ''high confidence'' ) ( [[#Anwar--2015|Anwar et al., 2015]] ; [[#Lobell--2015|Lobell et al., 2015]] ; [[#Prokopy--2015|Prokopy et al., 2015]] ; [[#Dreccer--2018|Dreccer et al., 2018]] ; [[#Nuttall--2018|Nuttall et al., 2018]] ; [[#Wang--2018a|Wang et al., 2018a]] ). Interactions of heat and drought could lead to even greater losses than heat alone ( [[#Sadras--2015|Sadras and Dreccer, 2015]] ; [[#Hunt--2018|Hunt et al., 2018]] ). Australian wheat yields are projected to decline by 2050, with a median yield decline of up to 30% in southwest Australia and up to 15% in southern Australia, with possible increases and decreases in the east ( [[#Taylor--2018|Taylor et al., 2018]] ; [[#Wang--2018a|Wang et al., 2018a]] ). In temperate fruit, accumulated winter chill for horticulture is projected to further decline ( [[#Darbyshire--2016|Darbyshire et al., 2016]] ). Winegrape maturity is projected to occur earlier due to warmer temperatures ( ''high confidence'' ) ( [[#Webb--2014|Webb et al., 2014]] ; [[#van%20Leeuwen--2016|van Leeuwen and Darriet, 2016]] ; [[#Jarvis--2018|Jarvis et al., 2018]] ; [[#Ausseil--2019b|Ausseil et al., 2019b]] ), leading to potential changes in wine style ( [[#Bonada--2015|Bonada et al., 2015]] ). Rice is susceptible to heat stress, and average grain yield losses across rice varieties range from 83% to 53% in experimental trials when heat stress is applied during plant emergence and grain fill stages ( [[#Ali--2019|Ali et al., 2019]] ). In Tasmania, wheat yields are projected to increase, particularly at sites presently temperature-limited ( [[#Phelan--2014|Phelan et al., 2014]] ).

New Zealand evidence on impacts across crops is very limited. Precipitation and temperature changes alone show minor effects on crop yield, and winter yields of some crops may increase (e.g., wheat, maize) ( [[#Ausseil--2019b|Ausseil et al., 2019b]] ). For temperate fruit, loss of winter chill may reduce yields in some regions and trigger impacts across supply chains ( [[#Cradock-Henry--2019|Cradock-Henry et al., 2019]] ) (11.5.1). Increased pathogens could damage the cut flower, guava and feijoa fruit growing and the honey and related industries ( [[#Lawrence--2016|Lawrence et al., 2016]] ). The combined effects of changes in seasonality, temperature, precipitation, water availability and extremes, such as drought, have the potential to escalate impacts, but understanding of these effects is limited.

Other climate-change-related factors complicate crop climate responses. When CO 2 was elevated from present-day levels of 400 to 550 ppm in trials, yields of rainfed wheat, field pea and lentil increased approximately 25% (0–70%). However, there was a 6% reduction in wheat protein that could not be offset by additional nitrogen fertilizer ( [[#O’Leary--2015|O’Leary et al., 2015]] ; [[#Fitzgerald--2016|Fitzgerald et al., 2016]] ; [[#Tausz--2017|Tausz et al., 2017]] ). Elevated CO 2 will worsen some pest and disease pressures, for example, barley yellow dwarf virus impacts on wheat ( [[#Trębicki--2015|Trębicki et al., 2015]] ). Warmer temperatures are also expanding the potential range of the Queensland fruit fly, including into New Zealand ( [[#Aguilar--2015a|Aguilar et al., 2015a]] ), threatening the horticulture industry ( [[#Sultana--2017|Sultana et al., 2017]] ; [[#Sultana--2020|Sultana et al., 2020]] ). Some crop pests (e.g., the oat aphid) are projected to be negatively affected by climate change ( [[#Macfadyen--2018|Macfadyen et al., 2018]] ), but so too are beneficial insects. There is large uncertainty in rainfall and crop projections for northern Australia (Table 11.3). For sugarcane, an impact assessment for CO 2 at 734 ppm using the A2 emission scenario at Ayr in Queensland projected modest yield increases ( [[#Singels--2014|Singels et al., 2014]] ). Climate change is projected to adversely impact tropical fruit crops such as mangoes through higher minimum and maximum temperatures, reducing the number of inductive days for flowering ( [[#Clonan--2020|Clonan et al., 2020]] ).

Climate change is projected to shift agro-ecological zones ( ''high confidence'' ) ( [[#Lenoir--2015|Lenoir and Svenning, 2015]] ; [[#Scheffers--2016|Scheffers et al., 2016]] ). This includes the climatically determined cropping strip bounded by the inner arid rangelands and the wetter coast or mountain ranges in mainland Australia ( [[#Nidumolu--2012|Nidumolu et al., 2012]] ; [[#Eagles--2014|Eagles et al., 2014]] ; [[#Tozer--2014|Tozer et al., 2014]] ). A narrowing of grain-growing regions is projected with a shift of the inner margin towards the coast under drier and warmer conditions ( [[#Nidumolu--2012|Nidumolu et al., 2012]] ; [[#Fletcher--2020|Fletcher et al., 2020]] ). The economic impact of the shift depends on adaptation ( [[#Sanderson--2015|Sanderson et al., 2015]] ; [[#Hunt--2019|Hunt et al., 2019]] ) and how resources, support industries, infrastructure and settlements adapt. Shifts in agro-ecological zones present some opportunities, for example warming is projected to be beneficial for wine production in Tasmania ( [[#Harris--2020|Harris et al., 2020]] ).

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===== 11.3.4.1.3 Adaptation =====

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Some farmers are adapting to drier and warmer conditions through more effective capture of non-growing-season rainfall (e.g., stubble retention to store soil water), improved water use efficiency and matching sowing times and cultivars to the environment ( ''high confidence'' ) ( [[#Kirkegaard--2011|Kirkegaard and Hunt, 2011]] ; [[#Fitzer--2019|Fitzer et al., 2019]] ; [[#Haensch--2021|Haensch et al., 2021]] ). Observed adaptations include new technologies that improve resource efficiencies, professional knowledge and skills development, new farmer and community networks and diversification of business and household income ( [[#Ghahramani--2015|Ghahramani et al., 2015]] ; [[#De--2016|De et al., 2016]] ). For Australian wheat, earlier sowing and longer-season cultivars may increase yield by 2–4% by 2050, with a range of −7 to +2% by 2090 ( [[#Wang--2018a|Wang et al., 2018a]] ). In the wheat industry, breeding for improved reproductive frost tolerance remains a priority ( [[#Lobell--2015|Lobell et al., 2015]] ). Modelling suggests that, since 1990, farm management has held Australian wheat yields constant, but declining rainfall and increasing temperature may have contributed to a 27% decline in simulated potential Australian wheat yield ( [[#Hochman--2017|Hochman et al., 2017]] ).

Other observed incremental adaptations include later pruning in the grape industry to spread harvest period and partially restore wine balance, with neutral effects on yield and cost ( [[#Moran--2019|Moran et al., 2019]] ; [[#Ausseil--2021|Ausseil et al., 2021]] ). The cotton sector increasingly requires shifts in sowing dates to avoid financial impacts ( [[#Luo--2017|Luo et al., 2017]] ). During years of low water availability, rice growers have been trading water and/or shifting to dry land farming ( [[#Mushtaq--2016|Mushtaq, 2016]] ).

Growers in New Zealand are changing the timing of their operations, growing crops within covered enclosures and purchasing insurance ( [[#Cradock-Henry--2015|Cradock-Henry and McKusker, 2015]] ) Teixeira et al. 2018). Investment of capital in irrigation infrastructure has increased ( [[#Cradock-Henry--2018a|Cradock-Henry et al., 2018a]] ), although its effectiveness as an adaptation depends on water availability (Box 11.5). In industries based on long-lived plants, such as the kiwifruit and grape industries, many of the adaptations (e.g., breeding and growing heat-adapted and disease-resistant varieties) have long lead times and require greater investment than in the cropping sector ( [[#Cradock-Henry--2020a|Cradock-Henry et al., 2020a]] ). While breeding programmes for traits with enhanced resilience to future climates are beginning, there is little evidence of strategic industry planning ( [[#Cradock-Henry--2018a|Cradock-Henry et al., 2018a]] ).

For drought management, balancing near-term needs with long-term adaptation to increasing aridity is essential ( [[#Downing--2016|Downing et al., 2016]] ). Insufficient and maladaptive decisions can have far-reaching effects, including changes to resources, infrastructure, services and supply chains to which others must adapt ( [[#Fleming--2015|Fleming et al., 2015]] ; [[#Graham--2018|Graham et al., 2018]] ). While there is potential for a greater proportion of agriculture to be located to northern Australia, there are significant and complex agronomic, environmental, institutional, financial and social challenges for successful transformation, including the risk of disruption ( ''medium confidence'' ) ( [[#Jakku--2016|Jakku et al., 2016]] ).

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==== 11.3.4.2 Livestock ====

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===== 11.3.4.2.1 Observed impacts =====

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Both the seasonality and annual production of pasture is changing ( ''high confidence'' ). In many regions, warming is increasing winter pasture growth ( [[#Lieffering--2016|Lieffering, 2016]] ); the effects on spring growth are more mixed, with some regions experiencing increased growth ( [[#Newton--2014|Newton et al., 2014]] ) and others experiencing reduced spring growth ( [[#Perera--2020|Perera et al., 2020]] ). Droughts are causing economic damage to livestock enterprises, with drought and market prices significantly affecting profit ( [[#Hughes--2019a|Hughes et al., 2019a]] ), in addition to the impacts on animal health and the livelihoods of pastoralists, periods of drought contribute to land degradation, particularly in the cattle regions of northern Australia ( [[#Marshall--2015|Marshall, 2015]] ). Heat load in cattle leads to reduced growth rates and reproduction, and extreme heat waves can lead to death ( [[#Lees--2019|Lees et al., 2019]] ; [[#Harrington--2020|Harrington, 2020]] ). Temperatures over 32°C reduce ewe and ram fertility along with the birth weight of lambs ( [[#van%20Wettere--2021|van Wettere et al., 2021]] ).

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===== 11.3.4.2.2 Projected impacts =====

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Some areas may experience increased pasture growth, but others may experience a decrease that cannot be fully offset by adaptation ( ''high confidence'' ) ( [[#Moore--2013|Moore and Ghahramani, 2013]] ; [[#Lieffering--2016|Lieffering, 2016]] ; [[#Kalaugher--2017|Kalaugher et al., 2017]] ). Climate change may modify the seasonality of pasture growth rates more than annual yields in New Zealand ( [[#Lieffering--2016|Lieffering, 2016]] ). In eastern parts of Queensland, climate change impacts on pasture growth are equivocal, with simple empirical models suggesting a decrease in net primary productivity ( [[#Liu--2017|Liu et al., 2017]] ), while mechanistic models that include increases in length of the growing season and the beneficial effects of CO 2 fertilisation indicate increases in pasture growth ( [[#Cobon--2020|Cobon et al., 2020]] ). In Tasmania, annual pasture production is projected to increase by 13–16%, even with summer growth projected to decline with increased interannual variability, resulting in a projected increase in milk yields by 3–16% per annum ( [[#Phelan--2015|Phelan et al., 2015]] ).

Extreme climatic events (droughts, floods and heatwaves) are projected to adversely impact productivity for livestock systems ( ''medium confidence'' ). This includes reduced pasture growth rates between 3–23% by 2070 from late spring to autumn and elevated growth in winter and early spring ( [[#Cullen--2009|Cullen et al., 2009]] ; [[#Hennessy--2016|Hennessy et al., 2016]] ; [[#Chang-Fung-Martel--2017|Chang-Fung-Martel et al., 2017]] ). Heavy rainfall and storms are projected to lead to increased erosion, particularly in extensively grazed systems on steeper land, reducing productivity for decades, reducing soil carbon ( [[#Orwin--2015|Orwin et al., 2015]] ) and increasing sedimentation. Increased heat stress in livestock is projected to decrease milk production and livestock reproduction rates ( ''high confidence'' ) ( [[#Nidumolu--2014|Nidumolu et al., 2014]] ; [[#Ausseil--2019b|Ausseil et al., 2019b]] ; [[#Lees--2019|Lees et al., 2019]] ). In Australia, the average number of moderate to severe heat stress days for livestock is projected to increase 12–15 d by 2025 and 31–42 d by 2050 compared to 1970–2000 ( [[#Nidumolu--2014|Nidumolu et al., 2014]] ). In New Zealand, an extra 5 (RCP2.6) to 7 (RCP8.5) moderate heat stress days per year are projected for 2046–2060 ( ''high confidence'' ) ( [[#Ausseil--2019b|Ausseil et al., 2019b]] ), which would especially affect animals transported long distances ( [[#Zhang--2019|Zhang and Phillips, 2019]] ) and strain the cold chains needed to deliver meat and dairy products safely. The distribution of existing and new pests and diseases are projected to increase, for example, new tick- and mosquito-borne diseases such as bovine ephemeral fever ( [[#Kean--2015|Kean et al., 2015]] ).

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===== 11.3.4.2.3 Adaptation =====

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Adaptations in both grazing and confined beef cattle systems require enhanced decision-making skills capable of integrating biophysical, social and economic considerations ( ''high confidence'' ). Social learning networks that support integration of lessons learned from early adopters and involvement with science-based organisations can help enhance decision-making and climate adaptation planning ( [[#Derner--2018|Derner et al., 2018]] ). Pasture management adaptations for livestock production include deeper rooted pasture species in higher rainfall regions ( [[#Cullen--2014|Cullen et al., 2014]] ) and drought-tolerant species ( [[#Mathew--2018|Mathew et al., 2018]] ). Soil and land management practices are important in ensuring soils maintain their supporting and regulating services ( [[#Orwin--2015|Orwin et al., 2015]] ). Adaptations in the primary sector in New Zealand are now positioned within the requirements of the National Policy Statement on Freshwater ( [[#MfE--2020b|MfE, 2020b]] ). Adaptations to manage heat stress in livestock include altering the breeding calendar, providing shade and sprinklers, altering nutrition and feeding times and more heat-tolerant animal breeds ( [[#Chang-Fung-Martel--2017|Chang-Fung-Martel et al., 2017]] ; [[#Lees--2019|Lees et al., 2019]] ; [[#van%20Wettere--2021|van Wettere et al., 2021]] ).

Beef rangeland systems in Queensland are projected to have benefits in the southeast through higher CO 2 and temperatures extending the growing season and reducing frost, but a warmer and drier climate in the southwest may reduce pasture and livestock production ( [[#Cobon--2020|Cobon et al., 2020]] ). Northern Queensland is most resilient to temperature and rainfall changes (production limited by soil fertility) while western/central west Queensland is most sensitive to rainfall changes, that is, low rainfall is associated with lower productivity ( [[#Cobon--2020|Cobon et al., 2020]] ). The social context of climate change impacts and the processes shaping vulnerability and adaptation, especially at the scale of the individual, are critical to successful adaptation efforts ( [[#Marshall--2014|Marshall and Stokes, 2014]] ).

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==== 11.3.4.3 Forestry ====

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===== 11.3.4.3.1 Observed impacts =====

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Climate change may have increased tree mortality in Australia’s commercial ''Eucalyptus globulus'' and ''Pinus radiata'' plantation forests ( [[#Crous--2013|Crous et al., 2013]] ; [[#Pinkard--2014|Pinkard et al., 2014]] ). Climate warming enhanced tree water use and vulnerability to heat ( [[#Crous--2013|Crous et al., 2013]] ). Increases in fire frequency and intensity in forests of southern Australia are leading to diminishing resources available for timber production ( [[#Pinkard--2014|Pinkard et al., 2014]] ) (Box 11.1).

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===== 11.3.4.3.2 Projected impacts =====

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The projected declines in rainfall in far southwest and far southeast mainland Australia are projected to reduce plantation forest yields ( ''high confidence'' ). Warmer temperatures are projected to reduce forest growth in hotter regions (between 7 and 25%), especially where species are grown at the upper range of their temperature tolerances, and increase plantation forest growth (&gt;15%) in cooler margins like Tasmania and the Victorian highlands (2030, A2); emission scenario A2 creates a warming trajectory slightly higher than the RCP6.0 warming scenario, but less than RCP8.5 ( [[#Rogelj--2012|Rogelj et al., 2012]] ; [[#Battaglia--2017|Battaglia and Bruce, 2017]] ). Elevated CO 2 is projected to increase forest growth if other biophysical factors are not limiting ( ''medium confidence'' ) ( [[#Quentin--2015|Quentin et al., 2015]] ; [[#Duan--2018|Duan et al., 2018]] ).

Forestry plantations are projected to be negatively impacted from increases in fire weather (Box 11.1), particularly in southern Australia ( ''high confidence'' ) ( [[#Pinkard--2014|Pinkard et al., 2014]] ). Increased pest damage due to temperature increases may reduce eucalyptus and pine plantation growth by as much as 40% in some Australian environments by 2050 ( [[#Pinkard--2014|Pinkard et al., 2014]] ). Increased heat and water stress may enhance insect pest defoliation for ''P. radiata'' in Australia (e.g., ''Sirex noctilio'' , ''Ips grandicollis'' and ''Essigella californica'' ) ( [[#Mead--2013|Mead, 2013]] ; [[#Pinkard--2014|Pinkard et al., 2014]] ).

Combined impacts from heavy rainfall, soil erosion, drought, fire and pest incursions are projected to increase risks to the permanence of carbon offset and removal strategies in New Zealand for meeting its climate change targets ( [[#PCE--2019|PCE, 2019]] ; [[#Watt--2019|Watt et al., 2019]] ; [[#Anderegg--2020|Anderegg et al., 2020]] ; [[#Schenuit--2021|Schenuit et al., 2021]] ). Effective management of the interactions between mitigation and adaptation policies can be achieved through governance and institutions, including Māori tribal organisations and sectoral adaptation, to ensure effective and continued carbon sequestration and storage as the climate changes ( ''medium confidence'' ) ( [[#Lawrence--2020b|Lawrence et al., 2020b]] ) (11.4.2) (Box 11.5). The productivity of radiata pine ( ''P. radiata D. Don'' ) in New Zealand due to higher CO 2 is projected to increase by 19% by 2040 and 37% by 2090, but greater wind damage to trees is expected ( [[#Watt--2019|Watt et al., 2019]] ). Changes in the distribution of existing weeds, pests and diseases with potential establishment of new sub-tropical pests and seasonal invasions are projected ( [[#Kean--2015|Kean et al., 2015]] ; [[#Watt--2019|Watt et al., 2019]] ; [[#MfE--2020a|MfE, 2020a]] ). Increased pathogens such as pitch canker, red needle cast and North American bark beetles could damage plantations ( [[#Hauraki%20Gulf%20Forum--2017|Hauraki Gulf Forum, 2017]] ; Lantschner, 2017; [[#Watt--2019|Watt et al., 2019]] ).

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===== 11.3.4.3.3 Adaptation =====

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Adaptation options include increased investment in monitoring forest condition and functioning; early detection and management of insect pests, diseases and invasive species; improved selection of land with appropriate growing conditions for plantation timber production under current and future conditions; trialling new species and genetic varieties; changing the timing and frequency of planned fuel reduction fires; introducing more fire-tolerant tree species where appropriate; reducing ignition sources; and maintaining access and emergency response capacity ( [[#Boulter--2012|Boulter, 2012]] ; [[#Pinkard--2014|Pinkard et al., 2014]] ; [[#Keenan--2017|Keenan, 2017]] ).

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==== 11.3.4.4 Marine Food ====

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===== 11.3.4.4.1 Observed impacts =====

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The ecological impacts of climate change on fisheries species have already emerged ( ''high confidence'' ) ( [[#Morrongiello--2015|Morrongiello and Thresher, 2015]] ; [[#Gervais--2021|Gervais et al., 2021]] ). This includes loss of habitats for fisheries species ( [[#Vergés--2016|Vergés et al., 2016]] ; [[#Babcock--2019|Babcock et al., 2019]] ) and poleward shifts in the distribution of barrens-forming urchins ( [[#Ling--2018|Ling and Keane, 2018]] ) impacting abalone and rock lobster fisheries. The percentage of reef as barrens across eastern Tasmania grew from 3.4% to 15.2% from 2001/2002 to 2016/2017, an approx. 10.5% increase per annum over the 15-year period ( [[#Ling--2018|Ling and Keane, 2018]] ). Oysters farmed from wild spat (Sydney rock oysters ''Saccostrea glomerata'' ) are most at risk from climate change, primarily due to observed increases in summer temperatures and heatwave-related mortalities ( [[#Doubleday--2013|Doubleday et al., 2013]] ). The exceptional 2017/2018 summer heatwave caused significant losses of farmed salmon in New Zealand, with farm owners seeking consent to move operations to cooler water ( [[#Salinger--2019b|Salinger et al., 2019b]] ).

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===== 11.3.4.4.2 Projected impacts =====

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Aquaculture is projected to be more easily adapted than wild fisheries to avoid excessive exposure to the physio-chemical stresses from acidification, warming and extreme events ( [[#Richards--2015|Richards et al., 2015]] ). In New Zealand, wild and cultured shellfish are identified as being most at risk from climate change ( [[#Capson--2014|Capson and Guinotte, 2014]] ). Changes in ocean temperature and acidification and the downstream impacts on species distribution, productivity and catch are projected concerns ( ''medium confidence'' ) ( [[#Law--2016|Law et al., 2016]] ) that impact Māori harvesting of traditional seafood and the social, cultural and educational elements of food gathering (mahinga kai) ( [[#MfE--2016|MfE, 2016]] ). Warm temperate hatchery-based finfish species (yellowtail kingfish ''Seriola lalandi'' ) are projected to be the least at risk, because of well-controlled environmental conditions in hatcheries and temperature increases, which are expected to increase growth rates and productivity during the grow-out stage ( [[#Doubleday--2013|Doubleday et al., 2013]] ). For wild fisheries, multi-model projections suggest temperate and demersal systems, especially invertebrate shallow-water species, would be more strongly affected by climate change than tropical and pelagic systems ( ''medium confidence'' ) ( [[#Pecl--2014|Pecl et al., 2014]] ; [[#Fulton--2018|Fulton et al., 2018]] ; [[#Pethybridge--2020|Pethybridge et al., 2020]] ). In New Zealand waters, available habitat for both albacore tuna and oceanic tuna ( [[#Cummings--2021|Cummings et al., 2021]] ) is expected to widen and shift.

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===== 11.3.4.4.3 Adaptation =====

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Selective breeding in oysters is projected to be an important global adaptation strategy for sustainable shellfish aquaculture that can withstand future climate-driven change to habitat acidification ( [[#Fitzer--2019|Fitzer et al., 2019]] ). Less than a quarter of fisheries management plans for 99 of Australia’s most important fisheries considered climate change, and only to a limited degree ( [[#Fogarty--2019|Fogarty et al., 2019]] ; [[#Fogarty--2021|Fogarty et al., 2021]] ). Implementation of management and policy responses to climate change have lagged in part because climate change has not been considered as the most pressing issue ( [[#Hobday--2017|Hobday and Cvitanovic, 2017]] ; [[#Fogarty--2019|Fogarty et al., 2019]] ; [[#Fogarty--2021|Fogarty et al., 2021]] ) (Cross-Chapter Box MOVING SPECIES in Chapter 5).

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