Editing IPCC:AR6/WGII/Chapter-5 (section)

==== 5.4.1.2 Observed impacts on other crops (vegetables, fruit, nut and fibre) ====

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The impact of climate change on these diverse crop types is under-researched and uncertain ( [[#Manners--2018|Manners and van Etten, 2018]] ; [[#Alae-Carew--2020|Alae-Carew et al., 2020]] ); there are reports of positive impacts in some cases, but overall the observed impacts are negative across all crop categories (Figure 5.3).

Above-ground annual crops consumed as vegetables, fruits or salad are essential for food security and nutrition (5.12). In temperate regions, climate change can result in higher yields ( [[#Potopová--2017|Potopová et al., 2017]] ; [[#Bisbis--2018|Bisbis et al., 2018]] ), while in subtropical/tropical regions, negative impacts from heat and drought take precedence ( [[#Scheelbeek--2018|Scheelbeek et al., 2018]] ). Different species have different sensitivities to heat and drought ( [[#Prasad--2017|Prasad et al., 2017]] ; [[#Scheelbeek--2018|Scheelbeek et al., 2018]] ) and to combinations of stresses ( [[#Zandalinas--2018|Zandalinas et al., 2018]] ). Above-ground vegetables are especially vulnerable to heat and drought stress during pollination and fruit set, resulting in negitive impacts on yield ( [[#Daryanto--2017|Daryanto et al., 2017]] ; [[#Sita--2017|Sita et al., 2017]] ; [[#Brás--2021|Brás et al., 2021]] ) and harvest quality ( [[#Mattos--2014|Mattos et al., 2014]] ; [[#Bisbis--2018|Bisbis et al., 2018]] ). Growers have already seen negative impacts from the expansion of pest and disease agents due to warming ( [[#5.4.1.3|Section 5.4.1.3]] ; Figure 5.3).

Below-ground vegetables include starchy roots and tubers that form a regular diet in many parts of the tropics and subtropics. Warming and climate variability has altered the rate of tuber development, with yield impacts varying by location, including yield increases in some cases ( [[#Shimoda--2018|Shimoda et al., 2018]] ; [[#Ray--2019|Ray et al., 2019]] ). These crops are considered stress tolerant but are more sensitive to drought than cereals ( [[#Daryanto--2017|Daryanto et al., 2017]] ). Impacts on water supply are critical as root crops are water-demanding for long periods, and highly sensitive to drought and heat events during tuber initiation ( [[#Dua--2013|Dua et al., 2013]] ; [[#Potopová--2017|Potopová et al., 2017]] ; [[#Brás--2021|Brás et al., 2021]] ).

Among perennial tree crops, only grapevine, olive, almond, apple, coffee and cocoa have received significant research attention. Concerns about climate impacts on harvest quality are widespread (Figure 5.3) ( [[#Barnuud--2014|Barnuud et al., 2014]] ; [[#Bonada--2015|Bonada et al., 2015]] ). In higher-latitude regions, the primary concern is the effect of temperature variability on harvest stability, pests and diseases and phenology (including fulfilment of winter chill requirements and risks due to early emergence in spring), ( [[#El%20Yaacoubi--2014|El Yaacoubi et al., 2014]] ; [[#Ramírez--2015|Ramírez and Kallarackal, 2015]] ; [[#Santos--2017|Santos et al., 2017]] ; [[#Gitea--2019|Gitea et al., 2019]] ). In lower-latitude regions, information is limited, but studies are focused on increased tree mortality and yield loss due to drought, heat and impacts from variability in the timing of the wet and dry seasons ( [[#Glenn--2013|Glenn et al., 2013]] ; [[#Ramírez--2015|Ramírez and Kallarackal, 2015]] ); see Box 5.7). In fruit trees, warming and climate variability have already affected fruit quality, such as acidity and texture in apples, or skin colour in grape berries ( [[#Sugiura--2013|Sugiura et al., 2013]] ; [[#Sugiura--2018|Sugiura et al., 2018]] ). The reliability and stability of harvests has been impacted by climate variability, changes in the distribution of pests and pathogens ( [[#Seidel--2014|Seidel, 2014]] ; [[#Bois--2017|Bois et al., 2017]] ), and the mismatch of important phenological events (such as bud emergence and flowering) ( [[#Guo--2015|Guo and Shen, 2015]] ; [[#Legave--2015|Legave et al., 2015]] ; [[#Ito--2018|Ito et al., 2018]] ; [[#Vitasse--2018|Vitasse et al., 2018]] ). Perennial crops are particularly vulnerable to these impacts as they are exposed throughout the year, with little potential for growers to adjust planting date or location. Negative impacts via disruption to phenology and pest dynamics are best studied in grapevine (see Box 5.2).

Among the fibre crops, cotton is particularly well studied. As cotton is heat tolerant and yield increases with extra plant growth, positive effects of increasing temperature are expected, but observed impacts have been mixed due to negative impacts on phenology and plant water status ( [[#Traore--2013|Traore et al., 2013]] ; [[#Chen--2015a|Chen et al., 2015a]] ; [[#Cho--2017|Cho and McCarl, 2017]] ). Negative impacts of climate change due to proliferation of the pest cotton bollworm are widely reported ( [[#Ouyang--2014|Ouyang et al., 2014]] ; [[#Huang--2020|Huang and Hao, 2020]] ).

The impacts of climate change on water availability (rainfall and irrigation supply) are an emerging issue. Increased occurrence of drought combined with limited access to irrigation water is already a key constraint; for example, Californian almonds are predicted to increase their potential geographical range under climate warming ( [[#Parker--2018|Parker, 2018]] ), yet a trend of increasing drought has already resulted in trees being removed due to lack of access to irrigation water ( [[#Keppen--2015|Keppen and Dutcher, 2015]] ; [[#Kerr--2018|Kerr et al., 2018]] ; [[#Reisman--2019|Reisman, 2019]] ).

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