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Table 1 Definition of vulnerability components (sensitivity, exposure, and adaptive capacity) for four sectoral areas to describe methods of assigning components. TR, thermal range; RCP, representative concentration pathway; CDL, cropland data layer: Tmax, maximum temperature; Tmin, minimum temperature; MACA, multivariate-adaptive constructed analogues

From: Diverse landscapes, diverse risks: synthesis of the special issue on climate change and adaptive capacity in a hotter, drier Southwestern United States

  Definition Sector
Rangelands (Havstad et al.) Forests (Thorne et al.) Specialty crops (Kerr et al.) Field crops (Elias et al.)
Exposure Exposure refers to the nature of the external stress imposed on a system. Complexity of input data for analyses typically defines complexity of exposure metrics and measures “Unquantified,” however, incorporated via discussion of abiotic stressors (i.e. precipitation, temperature) Bioclimatic envelope assuming exposed vegetation is within or beyond the most marginal 1% of the current climate space. Summer Tmax; Winter Tmin a. Summer Tmaxb. Crop-specific thermal tolerance based on historic TRc. Days with temperature > 35 °Cd. Cumulative hours of crop exposure per 1 °C increment from 32 to 34 °C and ≥ 35 °C
Historic Past climatic conditions (time-period varies by sector and, for field crops, analysis. na 50-year mean (1950–2000) of 19 bioclimatic variables. MACA downscaled county-level data; PRISM 30-year normals (1971–2000) a. PRISM 30-year mean (1971–2000)b. 30-year mean (1971–2000) and USDA CDL (4 km2). TR is 95% of summer Tmax coincident with crop location.c. Days > 35 °C April to August using MACA 20 model mean (1950–2005).d. 1950–2005 hourly temperature exposures April to August for 20 MACA models.
Future Future climatic conditions na Two climate models (MRI-CGCM3 and MIROC-ESM-CHEM (2061–2080) Mean of 20 CMIP-5 models (2040–2069) a. Mean of 20 CMIP-5 models (2040–2069)b. Same as a. (above)c. Days > 35 °C using mean of the 20 MACA models (2040–2069).d. 2040 to 2069 hourly temperature exposures (Tmax and Tmin) April to August for the 20 MACA models.
Emission scenario RCP from the coupled model intercomparison project 5 na RCP4.5 and RCP8.5 RCP8.5 RCP8.5
Sensitivity Sensitivity is the degree of negative or positive change induced in a system because of exposure to the effects of climate change. Sector-dependent definition including abiotic and biotic impacts, as well as socio-economic variables. Impact-driven from a livestock perspective (biophysical and socio-economic considerations; e.g. land degradation, reduced forage supply, increased heat stress, reduced livestock grazing-carrying capacity; reduced operations options) Endemic drivers of stress: wildfire, drought, pathogens, and pests (scored from 0 to 3). Literature synthesis to create a sensitivity index from 1 to 4 to both winter Tmin and summer Tmax. Biophysical (crop yield effects)a. Literature synthesis for crop sensitivity factor (SF) (scale 1 to 3) to summer Tmax.b. Shifts in and out of TRc. Areal extent with increased temperatured. Crop yield effects
Adaptive capacity Adaptive capacity describes management practices for helping the system tolerate changes in the magnitude, frequency, duration, and areal extent of external stressors. Response and adaptive capacity will rely upon proven management strategies of the past (reduced stocking rates, proper grazing management and diversified income, alternative forage supplies, and practices to reduce heat stress. Mechanistic species-specific response to disturbance (i.e. sensitivity): presence of fire-adaptive traits, modes of dispersal, seed longevity (scored from 1 to 3). Impact-based crop acreage/value. Adaptive measures discussed but not modeled (i.e. use of heat- and drought-tolerant crops). Adaptive measures discussed include increasing irrigation and water security, earlier planting—supported by spatially explicit vulnerability analysis, selecting and developing drought-tolerant cultivars, prioritize adaptation using spatially explicit methods.
Vulnerability Outcome vulnerability is the potential for climate change impacts on an exposure unit after feasible adaptations. Contextual vulnerability is influenced by biophysical conditions as well as dynamic social, economic, political, institutional, and technological factors (O’Brien et al. 2007). Contextual Outcome Outcome Outcome
Spatial unit of analysis Spatial area where variables (exposure, sensitivity, and adaptive capacity) are summarized and impacts evaluated NRCS Land Resource Regions (LRR)Major Land Resource Areas (MLRAs)Ecological site 1 km2 grid from LANDFIRE grouped into 10 major categories according to similar species composition, geographical distribution, and ecological function (summarized at SW, forest type, and US level III ecoregion scales). County level (California) County level (Southwest US) and 2012 crop locations as defined by the USDA Crop Data Layer
Spatial unit is a function of, but not the recommendation listed above. Factors used to define spatial unit of analysis Climate, land use, soils, vegetation Climate, modeled land types, soils, vegetation Political administration Political administration