According to the NCA5, Colorado is part of the Southwest region. 

Here are applicable Key Messages for the Southwest related to Agriculture and Land Use. 

Key: blue highlight = historical trends, yellow highlight = projected trends, and green highlight = both historical and projected trends. 

Summary

The Southwestern region of the United States is “among the fastest growing and most economically productive areas of the country… provid[ing] society with food, energy, and water” (18). However, the Southwest is currently experiencing increasing temperatures, as well as changes in timing, form, and amount of precipitation - which is expected to continue as the climate changes (2, 18). The long-term aridification and episodic drying in the western US has contributed to extended droughts, along with compounding events, that affect agriculture, forestry, and other land-based industries and activities (2). 

“Monitoring indicators of climate impacts on agriculture can improve understanding and help with adaptation efforts” (20)

Figure 28.6: "Climate change impacts to the Southwest's agriculture include longer growing seasons, a northward shift in plant hardiness zones, expanded areas of heat stress, and higher rates of evapotranspiration, increasing demand for fresh water for irrigation. Monitoring the indicators helps us understand how impacts are experienced and how to adapt to risks. Figure credit: New Mexico State University and Utah State University" (20).

• Temperatures are increasing - including “annual average minimum temperatures, growing degree days, and average number of days above 86°F (the threshold used to define heat zones)” - which will result in “longer growing seasons, a northward shift in plant hardiness zones, and expanded areas of heat stress exposure to crops and livestock” (20). For Colorado and the intermountain west, “false springs” are expected to increase vulnerability of crops to “late-season freeze events” (20). 
• Drought: While the Southwest has historically experienced “episodes of intense drought and precipitation,” the Southwest and Great Plains regions will experience the greatest increase in climatic water deficit (CWD) of the United States - meaning, these regions will experience a great shortfall of water necessary to fulfill supply vegetation requirements (19, 2). 
• Floods: Many areas in the Southwest have already experienced damaging floods, and increasing flood activity can threaten human environments - including structures and water quality - as well as natural environments (3). In urban areas, surfaces such as concrete, asphalt, and pavement do not absorb water, which can lead to intense, concentrated floods (3). Meanwhile, rural areas may experience less concentrated floods, except where intensive agriculture has reduced the infiltration and capacity of soils; this creates an increase in runoff, which results in flooding (3). Large-scale floods can also cause disruptions to transportation infrastructure as well as agricultural production (3). 
• Changes in precipitation: While much of the United States is expected to receive an increase in precipitation, the Southwest will experience a decrease, which may have a disproportionate influence on the region’s water resources compared to other regions in the US (2). These changes in precipitation and additional changes in temperature will exacerbate drought conditions (2). 
• Reduced flows in major river basins such as the Colorado and Rio Grande are expected to affect the landscape on a large scale; in addition, the effect of climate change on watersheds can be amplified by “gradual and episodic stressors” (19, 9)

"Climate effects on watersheds exemplify the amplifying impacts of gradual and episodic stressors" (9) 

Figure 8.4: "Both gradual and episodic (short-lived) climatic drivers alter the transport of water, nutrients, and sediments from terrestrial watersheds to downstream water bodies. These drivers affect aquatic ecology and ecosystem services throughout the hydrological system, even in areas distant from drivers of change (e.g., more intense rainfall leading to leaching of fertilizers that stimulate harmful algal blooms downstream). The frequency and intensity of episodic extreme events is projected to increase (KM2.2), raising risks for many species (Figure 8.10). Figure credit: Cary Institute of Ecosystem Studies" (9).

• Changes in evapotranspiration: Actual evaporation, or the “water that evaporates from soil and surface water or transpires from plants,” will decrease in the Southwest as rates of evapotranspiration increase (2, 20). 
• Soil moisture decreases: While more soil moisture observations are needed, it seems that soil moisture may increase if areas in the Southwest receive more summer precipitation in the future (2). However, there is consensus that soils are becoming drier in the Southwest and that the region will most likely experience decreasing annual soil moisture (2). While this will affect all agricultural industries, the “producers most vulnerable to local precipitation deficits are dryland farmers growing rain-fed crops and producers raising livestock on rangelands” (20). Furthermore, wind erosion and dust production from exposed soils are expected to increase, which will require “careful management… [of] agricultural practices such as fallowing and grazing” (20). 
• Changes in snowpack and groundwater: Since mountain snowpack is “one of the most important sources of water in the Southwest… declines in western snowpack over the last century” will affect water availability throughout the region (19). Acequias, “community-based snow-fed irrigation systems in high-elevation watersheds of New Mexico and Colorado,” will be disproportionally affected by decreasing snowpack (20). While irrigated agriculture in the Southwest was initially “thought to be less vulnerable to climate change than… other parts of the country,” this reliance on irrigation makes the Southwest more vulnerable to climate change as the “future irrigation supply is uncertain… depend[ing] on dwindling ground and surface water supplies” (20). In addition, natural groundwater recharge will decrease slightly in the Southwest, which, along with increasing temperatures, will increase irrigation demand (2). This may lead to an increase in demand for groundwater pumping, which in turn can reduce streamflow (3, 11). 
• Ecosystem services: Effects of drier conditions include changes in ecosystem composition, including those of insects and diseases that may affect agriculture, forestry, and other land-based industries (5). Additionally, since climate change is projected to affect forest growth, wood and paper industries will experience impacts of varying strengths depending on both the condition of the ecosystem and the management actions taken in response (6). The strength of climate change effects on forest ecosystems is “uncertain due to disturbances, such as droughts, wildfires, insects, and diseases, that limit forest growth” (6). 

"Ecosystems provide a broad range of relational benefits, from the material to the spiritual" (11) 

Figure 8.17: "Ecosystem services, also called "nature's contributions to people," are the benefits that humans receive or derive from ecosystems. These are both material (e.g., energy sources) and non-material (e.g., sense of place), and contribute to the regulation of ecosystem processes. The broad categories of benefits pictured are fluid and overlapping. People value nature in multiple ways, such as "living as" nature (Figure 16.3) or "living from" nature (e.g., people's dependency on key services). Adapted from O'Connor and Kenter 2019" (11).

• Recreation industries will also experience impacts due to climate change; warming temperatures and reduced snowpack have negatively impacted winter sports while positively impacting some summer sports; however, summer sports have also been impacted by smoke due to increasing wildfires (6, 7). Additional tourism-based industries, such as birdwatching, may impact communities dependent on local populations as range shifts occur due to climate change (10). 
• Ecosystem changes: Ecosystem transformation can be “gradual or relatively abrupt,” depending on the complexity and resilience of the system; ecosystems with “higher biodiversity have more species interactions and often exhibit slow changes at first followed by abrupt shifts” (9). However, “multiple stressors” can interact, leading to more abrupt changes (9). In the Southwest, sagebrush ecosystems are an example of ecosystem transformation and management. (Learn more about the NC CASC’s Rapid Climate Assessment Program (RCAP), many of which involve sagebrush ecosystems, here.) Additionally, changes in phenology - the timing of seasonal events - and changes in species’ ranges are expected in the Southwest; this will have impacts on a variety of land-based industries, including agriculture, as harvesting times, planting times, and species ranges shift in response to climate effects (10). 

"Climate change interacts with other stressors to cause synergistic effects, and resulting ecosystem changes can be abrupt and difficult to reverse" (9). 

Figure 8.6: "In western US, drought and longer, hotter growing seasons combined with invasive grasses and overgrazing have transformed sagebrush shrublands past a tipping point into annual grasslands that experience more frequent wildfires and no longer support native biodiversity and livestock grazing. Removing invasive grasses and seeding with native plants often does not restore the original shrubland ecosystem. Adapted from Foley et al. 2015" (9).

• Effects on threatened species: local-scale conditions can create complex patterns of environmental stressors, and conditions are changing faster in some places than others; this creates climate refugia, which are expected to support specialized and often threatened species (10). These refugia, along with corridors that connect them, will be particularly impacted by the effects of climate change and may disappear altogether (10). 

"Climate refugia are locations where environmental conditions are changing more slowly than the surrounding region" (10). 

Figure 8.12: "Refugia help populations survive extreme events, and when connected via dispersal currents and corridors can serve as rescue sites. Understanding variations in environmental exposures and organism sensitivities to extreme conditions helps forecast climate impacts and inform management strategies. Adapted from Morelli et al. 2016" (10).

• Disease risk in humans and wildlife: As increased temperatures and changes in precipitation occur, numerous diseases are “becoming more common as climate change expands vector ranges and changes species interactions and habitat preferences” (10). For example, “viral hemorrhagic septicemia damages wild and farm-raised fish such as rainbow trout, with patterns of spread and establishment being highly correlated with climatic variables (temperature and precipitation)” (10). 
• Invasive species: Climate change can have positive, negative, or net-zero effects on invasive species, depending on the species’ tolerance for temperature and precipitation as well as their ability to adapt (10). 
• Mountain pine beetles, while not an invasive species, are having “larger, more frequent, and more severe outbreaks… negatively affecting the quality and quantity of timber available to the region’s forestry and forest products industries (20). 

• Wildfires, although a natural and necessary part of Southwestern ecosystems, have been intensified by both climate change and “long-standing policies and forest management” (21). Specifically, practices of “fire suppression, widespread logging and livestock grazing, and elimination of Indigenous fire use” in combination with climate change have “contributed to high tree densities, compromised ecosystem function, and the diversity or heterogeneity of forest attributes such as species, size classes, and geographic distributions” (21). Therefore, forests and “fire-prone wildlands” in the Southwest “are susceptible to climate-mediated impacts including droughts, pests and disease, and devastating wildfire” (21). 

  Wildfires in the Southwest have increased in size, severity, and frequency, “with clear evidence of climate change as a major cause” (21). Wildfires have also caused ecosystem transformations; for example, “semiarid to arid forest systems… have experienced conversion to native grassland, shrubland, or non-native grassland” (21). In addition to impacts on “watersheds and aquatic resources,” ecosystem transformation due to wildfire “include  degradation of riparian systems; risks to riparian and riverine species, as well as to threatened and endangered species, from erosion caused by extreme precipitation events; and increased invasions by non-native species” (21). Postfire conditions for “water availability, quantity, and quality” have led to “interactions between wildfire and natural drought variability [which is] expected to increasingly exacerbate dry conditions… and drive future shifts in species composition or vegetation type” (21). Certain ecosystems are more vulnerable to postfire transformation than others, such as sagebrush ecosystems (learn more about the NC CASC’s Rapid Climate Assessment Program (RCAP), many of which involve sagebrush ecosystems, here). 

“Climate change is leading to larger and hotter fires and resulting in shifts in vegetation” (21). 

Figure 28.9: "Data from the states of California, Arizona, Colorado, and New Mexico show that approximately half (about 50%) of vegetation type change (e.g., forests transiting to shrublands or grasslands) is a function of high-severity fire. Adapted from Guiterman et al. 2022" (21).

Wildfires will impact human structures and property as well, such as the 2021 Marshall Fire in Colorado, which “burned more than 1,000 homes in just a few hours” (21). Wildfires are expected to affect most, if not all, land-based industries in the Southwest; however, particularly vulnerable industries “include wineries, tourism, forest products, and legal cannabis cultivation” (21).  

• Effects on human health and food security: Increased average and extreme temperatures are negatively affecting the health of farmers and outdoor workers in the Southwest (12). In addition, changes in temperature and precipitation will affect agriculture, which can in turn affect food security (14). This will have uneven impacts on food-insecure households in addition to “subsistence-based people” (14). In addition, rural communities may be threatened by compounding risks of climate change and “structural trends such as dependence on goods produced outside the area, digitization of economic and social life, and demographic change that may reduce resilience and rural quality of life” (15). 
• In areas of the Southwest where crop production is “unprofitable or infeasible,” livestock production is the dominant use of agricultural land (20). Climate change is expected to negatively impact the “livestock food supply chain, affecting production and nutritional quality of forage, livestock health on rangelands and in transport due to heat stress and pest exposure, and shelf life of products during transport and storage” (20). 

“Climate change has cascading and compounding effects on all stages of the food supply chain” (14)

Figure 11.10: "Extreme events fueled by climate change (first row, icons) can affect each stage of the food supply chain (second row, dark blue), resulting in compounding and cascading effects on the food system (third row, light blue). Adapted with permission from Davis et al. 2021" (14).

How are communities addressing these changes?

• Water policy innovations, such as those implemented by Colorado, are encouraging “rural-to-urban transfers while minimizing impacts in rural areas; [however] adoption has been slow due to distrust on the part of agricultural communities and uncertainty about trade-offs” (20). 
• Monitoring networks - for both species and ecosystems - can help reduce risks of abrupt ecosystem transformation (9). In addition, adaptive management, or “iteratively planning, implementing, and modifying strategies for managing resources,” can help to coordinate efforts, manage uncertainty, and provide “decision-making processes” (9). The Resist-Accept-Direct (RAD) framework is one way managers have examined decisionmaking under uncertain climate futures. The NC CASC is contributing to an ongoing Cross-Park RAD project with resource managers at the Glacier National Park and the Confederated Salish and Kootenai Tribes - learn more here! 
• Nature-based solutions (NBSs), or “ecosystem-based mitigation and adaptation opportunities,” are another pathway for adapting management practices to climate change; when NBSs are “managed in collaboration with affected communities and… local knowledge,” these can be effective solutions for addressing multiple management goals in an inclusive, cost-effective method (11). Ecosystem-based adaptations, a type of NBS, have been used in solutions such as “protecting and restoring floodplains to help reduce flood impacts or helping farmers cope with drought through soil conservation measures” (11). 
• Agroecology is an agricultural practice utilizing applied “ecological concepts, principles, and knowledge” to form “sustainable agricultural ecosystems… [that] includes the roles of human beings as a central organism” (13). Agroecology can include “matching species to the environment, organic matter-driven nutrient cycling, integrated management, and natural pest controls,” which can result in reduced reliance on chemical inputs, increased ecosystem diversity, and potentially, reduction of greenhouse gas emissions (13). Emissions from US agriculture, which have increased over the last thirty years, are still increasing; however, utilization of alternative farming techniques, increases in overall productivity, and implementation of new technology can decrease these emissions (13). 
• Improving irrigation efficiency faces barriers such as “farm or ranch location, access to surface water and groundwater, water rights, current irrigation methods, and crop types;” however, advancing irrigation efficiency can “reduce risks to farming and ranching operations [caused by] increasing temperatures, unreliable precipitation, and reduced water resources” (20). 
• Adaptive livestock management can reduce the livestock industry’s significant greenhouse gas emissions through “ruminant feed supplements and energy capture from liquid manure systems” (13). 

"Agroecological approaches seek to achieve beneficial agricultural outcomes while promoting ecosystem services and rural livelihoods" (13) 

Figure 11.5: "Science-based application of agroecological approaches results in outcomes that balance agricultural productivity and profitability with ecosystem services and societal well-being. Figure credit: USDA" (13).

• Alternative protein sources, such as plant-based meats, also offer a reduction in greenhouse gas emissions; while some approaches require establishment of infrastructure (thus resulting in more “energy inputs per unit of food production”), balancing this with the impacts of protein production and animal agriculture can result in a reduction of emissions. (13) 
• “Adaptive conservation management approaches” aim to reduce soil disturbance while “maximizing soil cover, biodiversity, and the presence of living roots” (20). Strategies such as cover cropping and reduced- or no-tillage farming are examples of adaptive conservation management (20). 
• Localized adaptation strategies, such as “crop- and locality- specific combinations of irrigation, site management (e.g., use of cover crops), and cultivar selection,” have been implemented across the Southwest (20). In addition, “climate change poses risks to productivity and quality of [produce, requiring adaptations on farms and throughout the supply chain, including changes in crop calendars, nutrient and pest management strategies, post-harvest, and preservation methods” (20). 

“Greenhouse gas emissions from protein production vary greatly according to protein type” (13)

Figure 11.8: "Estimated greenhouse gas (GHG) emissions from protein production vary widely depending on food type. Global median emissions (in kg of carbon dioxide [CO2] equivalents for every 100g of protein produced) are shown here for 11 major protein sources. Although cereal grains have lower protein content, they are included here because they contribute 41% to global protein intake. While US emissions values may differ slightly from global values, the relative differences in GHG emissions by protein intake. Figure credit: USDA, NOAA NCEI, and CISESS NC" (13).

• Tribes are utilizing increased funding to transition towards renewable energy, resulting in higher resilience to climate change, self-determination and sovereignty in energy production, and income opportunities from renewables. 

“The breadth of project type and funding amounts have increased for federally funded renewable energy projects” (17)

Figure 16.4: "The figure shows federally funded Tribal renewable energy and energy-efficiency projects between 1994 and 2022. The size of the circles indicates the number of projects: the larger the circle, the more projects of that energy type were funded that year. Historically, projects like retrofitting to improve energy efficiency, as well as renewable energy projects including solar, wind, and biomass, often received funding. The more recent trend toward microgrid and solar projects mirrors efforts to build Tribal energy sovereignty. Figure credit: DOI, NOAA NCEI, and CISESS NC" (17).

• Resilience to wildfires “may be enhanced by thinning trees, leveraging low- and moderate-severity wildfires with traditional forest management treatments that adjust fuels, and better incorporating managed wildfire;” utilizing a combination of prescribed fire and “mechanical forest treatments, such as thinning or pruning, also reduces tree densities and fuels,” which can also increase resilience (21). 
• Cultural burning practices by Indigenous and Tribal communities “can be compatible with traditional fire application and help advance increased resilience to climate change” (21). 
• Power shutoff policies have been implemented in some areas of the Southwest “to reduce wildfire risk when extreme wind events are predicted to topple powerlines and telecommunications infrastructure” (21). By preemptively shutting off power sources, decisionmakers can avoid occurrences of compound events of extreme winds, power loss, and wildfire (21).