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Fire and postfire debris flows increasingly threaten infrastructure and public safety as a warming climate and increased drought raise the risk of large, intense fires.18'19'20'21 Notable among recent examples was the debris flow following the Thomas Fire in Southern California, which killed 23 people, damaged 558 structures, closed a major highway for 13 days, and caused more than $1.15 billion in damages (in 2022 dollars; Figure 6.5).22'23 Risks to water supply and quality continue for years after a fire, as erosion washes excess sediment and pollutants downstream,24 shortening the lifespan of water-storage reservoirs.24'25 26 Sediment production is projected to double in one-third of western US watersheds by 2050 due to increased fire and extreme rain.26 The Southwest faces additional challenges to infrastructure and public health and safety from increased airborne dust,27,28,29 which can carry human disease and result in traffic accidents.30,31 Vegetation loss during drought can cause marginally stable land to transition to actively migrating sand dunes, some of which damage buildings and roads.32,33 Agriculture: Crops and Rangelands Land provides essential services by supporting the production of food for people, feed for animals, and forage for wildlife. Crop yields in the US continue to increase but are subject to large year-to-year fluctuations driven by environmental stresses34 35 and have become increasingly sensitive to water availability over the past two decades.36 Yield loss associated with warming has resulted primarily from drought, with heat stress playing a secondary role.37 Flooding also causes crop damage; during 1981-2016 in the US, inundation-induced yield loss was comparable in magnitude to that caused by extreme drought.38 In arid and semiarid lands of the Southwest, livestock overgrazing, oil and gas extraction, and off-road vehicle use amplify the effects of warming39 by damaging vegetation and biological soil crusts,40 further increasing dust production. Forests and Biodiversity Forests provide critical value to society by supplying a wide range of wood products, protecting water quality, supporting biodiversity, and providing recreational opportunities and spiritual and cultural benefits. Forest land cover can reduce warming locally by providing increased evaporation and shade.42 The effects of land-use change on forest goods and services, including the value of biodiversity, are still being explored.43'4445 In some cases, forest management can increase biodiversity and offset regional losses due to urbanization, but future losses of biodiversity due to climate change may be greater than reforestation offsets.46 Multiple interacting factors drive changes in goods and services from forest lands, including development, abandonment and expansion of agricultural land, and incentives for reforestation and conservation.47 Mixed land uses such as agroforestry are expected to increase soil water infiltration compared to agriculture alone, providing protection against warming, drought, and soil erosion due to overland flow during extreme precipitation events.48 Forest land-use transitions intended to mitigate climate change must be carefully assessed to prevent unintended consequences, such as net losses of carbon, biodiversity, habitat, soil quality, or other ecosystem services when converting mature forest to bioenergy crop cultivation (e.g., Harper et al. 201849).