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

=== 5.11.1 Current and Future Climate Change Impacts on Food Safety ===

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Emerging food safety risks from climate change include those posed by toxigenic fungi, plant- and marine-based bacterial pathogens, HABs and increased use of chemicals (plant protection products, veterinary drugs) potentially leaving residues in food (European Food Safety Authority Panel on Plant Protection Products and their Residues et al., 2017; [[#Deeb--2018|Deeb et al., 2018]] ; [[#Mbow--2019|Mbow et al., 2019]] ; [[#FAO--2020|FAO et al., 2020]] ).

Mycotoxins, produced by toxigenic fungi found on many crops, contaminate food and feed and cause a wide range of adverse impacts to human and animal health. Climate change can affect the growth and geographical expansion of these fungi ( ''high confidence'' ) ( [[#Wild--2015|Wild et al., 2015]] ; [[#Battilani--2016|Battilani, 2016]] ; [[#FAO%20and%20WHO--2016|FAO and WHO, 2016]] ; [[#Watson--2016b|Watson et al., 2016b]] ; [[#Alshannaq--2017|Alshannaq and Yu, 2017]] ; [[#Chen--2018a|Chen et al., 2018a]] ; [[#Avery--2019|Avery et al., 2019]] ; [[#Milicevic--2019|Milicevic et al., 2019]] ; [[#Van%20der%20Fels-Klerx--2019|Van der Fels-Klerx et al., 2019]] ; [[#FAO--2020a|FAO, 2020a]] ; [[#FAO--2020|FAO et al., 2020]] ).

''Aspergillus flavus'' is a fungus that infects a range of crops and can reduce grain quality. Several strains also produce aflatoxin, a particularly problematic mycotoxin ''.'' Increasing CO 2 and drought stress has little effect on growth of ''Aspergillus'' but significantly increases the production of aflatoxin ( [[#Medina--2015b|Medina et al., 2015b]] ).

In Europe, one estimate is that the risk of aflatoxin contamination will increase in maize in a +2°C temperature scenario in Europe, with nearly 40% of Europe exceeding the current legal limits (Battilani and Toscano, 2016). In Malawi, maize aflatoxin levels above European Union (EU) legal thresholds are possible for most of the country by mid-21st century (Warnatzsch and Reay, 2020). The occurrence of toxin-producing fungi will increase and expand from tropical and subtropical areas into new regions and where appropriate capacity for surveillance and risk management is lacking ( ''medium confidence'' ) ( [[#Miller--2016|Miller, 2016]] ). The increase in toxigenic fungi in crops, and consequent contamination of staple foods with mycotoxins, will increase the risks of human and animal exposure ( ''high confidence'' ) (Botana and Sainz, 2015; [[#Rose--2015|Rose and]] [[#Wu--2015|Wu, 2015]] ; [[#Battilani--2016|Battilani, 2016]] ; [[#Avery--2019|Avery et al., 2019]] ; [[#Bosch--2019|Bosch et al., 2019]] ; [[#Milicevic--2019|Milicevic et al., 2019]] ; [[#Moretti--2019|Moretti et al., 2019]] ; [[#Van%20der%20Fels-Klerx--2019|Van der Fels-Klerx et al., 2019]] ; [[#FAO--2020a|FAO, 2020a]] ).

In aquatic systems, toxins produced during HABs also cause food safety problems ( ''high confidence'' ) ( [[#Botana--2016|Botana, 2016]] ; [[#Estevez--2019|Estevez et al., 2019]] ; [[#5.8|Section 5.8]] ). Increased poleward expansion of ''Vibrio'' in coastal mid- to high-latitude areas has been observed ( [[#Baker-Austin--2017|Baker-Austin et al., 2017]] ). ''Vibrio'' -related mortalities from finfish consumption are expected to rise with climate change (water temperature, salinity, oxygen and pH) ( ''medium confidence'' ) ( [[#Mohamad--2019a|Mohamad et al., 2019a]] ; [[#Mohamad--2019b|Mohamad et al., 2019b]] ). For shellfish species, oxygen deficits ( [[#Mohamad--2019b|Mohamad et al., 2019b]] ), sea level rise ( [[#Deeb--2018|Deeb et al., 2018]] ) and temperature ( [[#Green--2019|Green et al., 2019]] ) will be most important for food safety.

Food safety is also anticipated to worsen from increased contaminant bioaccumulation under climate-induced warming ( ''high confidence'' ) (Sections 3.5.8, 3.5.9, 5.8, 5.9, [[#Bindoff--2019|Bindoff et al., 2019]] ;), with changes in pathogen, parasite, fungi and virus abundance and virulence ( [[#Bondad-Reantaso--2018|Bondad-Reantaso et al., 2018]] ). Coastal communities who depend on fisheries for livelihoods and nutrition are especially vulnerable ( [[#Hilmi--2014|Hilmi et al., 2014]] ; [[#Golden--2016|Golden et al., 2016]] ; [[#Bindoff--2019|Bindoff et al., 2019]] ).

Occurrence of bacterial pathogens such as ''Salmonella'' and ''Campylobacter'' will increase with rising temperatures ( ''high confidence'' ). Foodborne pathogen risks will increase through multiple mechanisms, though in general the impacts of climate change on different pathogens are uncertain ( [[#Akil--2014|Akil et al., 2014]] ; [[#Hellberg--2016|Hellberg and Chu, 2016]] ; [[#Lake--2018|Lake and Barker, 2018]] ). Even species within a genus can be affected differently. For example, higher CO 2 levels depress the growth rate of ''F. graminearum'' , an economically important pathogen on barley but have little effect on ''F. verticillioides'' , which is the most reported fungal species infecting maize.

Increases in rainfall intensity will have some effect on the transport of heavy metals by enhancing runoff from soil and increasing the leaching of heavy metals into water systems, with magnitudes dependent on local conditions ( ''high confidence'' ) ( [[#Joris--2014|Joris et al., 2014]] ; [[#Wijngaard--2017|Wijngaard et al., 2017]] ). Methyl mercury (MeHg) is highly neurotoxic and nephrotoxic and bioaccumulates and biomagnifies through the food web via dietary uptake (fish, seafood, mammals) ( [[#Fort--2016|Fort et al., 2016]] ). Ocean warming facilitates methylation of mercury, and the subsequent uptake of methyl mercury in fish and mammals has been found to increase by 3–5% for each 1°C rise in water temperature ( [[#Booth--2005|Booth and Zeller, 2005]] ; [[#FAO--2020a|FAO, 2020a]] ). A changing climate will release mercury from snow and ice, raising the amount of mercury in aquatic ecosystems, although its importance relative to industrial sources is unknown ( [[#Morrissey--2005|Morrissey et al., 2005]] ).

Increased frequency of inland floods has been associated with contamination of food with toxic and fat-soluble persistent organic pollutants (POPs), polychlorinated biphenyls (PCBs) and dioxins ( [[#Lake--2014|Lake et al., 2014]] ; [[#Tirado--2015|Tirado, 2015]] ; [[#Alava--2017|Alava et al., 2017]] ). Exposure to POPs can lead to serious health effects, including certain cancers, birth defects and impairments to the immune, reproductive and neurological systems.

Climate change–contaminant interactions may alter the bioaccumulation and biomagnification of POPs and PCBs as well as MeHg ( [[#Alava--2017|Alava et al., 2017]] ). Of particular concern is the pollution risk influenced by climate change in Arctic ecosystems and the bioamplification of POPs and MeHg in seafoods resulting in long-term contamination of traditional foods in Indigenous communities ( [[#Tirado--2015|Tirado, 2015]] ; [[#Alava--2017|Alava et al., 2017]] ).

The high risk associated with emerging zoonoses (animal diseases that can infect humans) and alterations in the distribution, survival and transmission of vectors and associated pathogens and parasites could lead to an increased use of veterinary drugs and more rapid development of microbial resistance (European Food Safety Authority et al., 2020; [[#FAO--2020a|FAO, 2020a]] ) and higher veterinary drug residues in food of animal origin, potentially posing health issues for humans ( [[#Beyene--2015|Beyene et al., 2015]] ; [[#FAO--2018|FAO et al., 2018]] ; European Food Safety Authority et al., 2020). These outcomes will depend, at least in part, on the extent of changes in current regulatory systems for veterinary drugs. Pre-harvest stress on animals can increase the contamination of meat products with zoonoses. Climate change may also increase rodent populations and rodent-born zoonoses ( [[#Naicker--2011|Naicker, 2011]] ). Extreme weather events that cause flooding, such as hurricanes or extreme rain events, increase the chance of inundating areas that contain waste from animal farms where antibiotics are used for production, increasing the spread of antibiotic-resistant bacteria into the surrounding environment ( [[#FAO--2020a|FAO, 2020a]] ).

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