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

==== 5.5.3.2 Impacts of increased temperature on livestock ====

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Recent research confirms the seriousness of the heat stress issue ( ''medium evidence'' , ''high agreement'' ). Considerable increases are projected during this century in the number of ‘extreme stress’ days per year for cattle, chicken, goat, pig and sheep populations with SSP5-8.5 but many fewer with SSP1-2.6 ( [[#Thornton--2021|Thornton et al., 2021]] : Figure 5.12; see Cross-Chapter Box MOVING PLATE in this chapter). Resulting impacts on livestock production and productivity may be large, particularly for cattle throughout the tropics and subtropics and for goats in parts of Latin America and much of Africa and Asia. Pigs are projected to be particularly affected in the mid-latitudes of Europe, East Asia and North America. [[#Lallo--2018|Lallo et al. (2018)]] estimated that global warming of 1.5°C and 2°C may exceed limits for normal thermo-regulation of livestock animals and result in persistent heat stress for animals in the Caribbean. Breed differences in heat stress resistance in dairy animals are now being quantified ( [[#Gantner--2017|Gantner et al., 2017]] ), as are effects on sow reproductive performance in temperate climates ( [[#Wegner--2016|Wegner et al., 2016]] ). Estimates of losses in milk production due to heat stress in parts of the USA, UK and West Africa to the end of the century range from 1% to 17% ( [[#Hristov--2018|Hristov et al., 2018]] ; [[#Fodor--2018|Fodor et al., 2018]] ; Wreford and Topp, 2020; [[#Rahimi--2020|Rahimi et al., 2020]] ). Much larger losses in dairy and beef production due to heat stress are projected for many parts of the tropics and subtropics: these could amount to USD 9 billion per year for dairy and USD 31 billion per for beef to end-century under SSP5-8.5, approximately 5% and 14% of the global value of production of these commodities in constant 2005 dollars.

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[[File:3750c6aa5275494e5a09d0fbf3baa129 IPCC_AR6_WGII_Figure_5_012.png]]

'''Figure 5.12 |''' '''Change in the number of days per year above ‘extreme stress’ values from the early 21st century (1991–2010) to end of century (2081–2100), estimated under SSP1-2''' '''.''' '''6 and SSP5-8.5 using the Temperature Humidity Index (THI).''' Mapped for species current global distribution ( [[#Gilbert--2018|Gilbert et al., 2018]] ) (grey areas, no change). ( [[#Thornton--2021|Thornton et al., 2021]] ), Also see Annex I: Global to Regional Atlas.

In many LMICs, poultry contribute significantly to rural livelihoods, including via modest improvements in nutritional outcomes of household children ( [[#de%20Bruyn--2018|de Bruyn et al., 2018]] ). Rural poultry are generally assumed to be hardy and well adapted to stressful environments, but little information exists regarding their performance under warmer climates or interactions with other production challenges ( [[#Nyoni--2019|Nyoni et al., 2019]] ).

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