2.2.2.2. Assessing the ‘Sensitivity’ Component of Climatic Vulnerability

The methods to be used for assessing ‘sensitivity’ depend on the particular sector and theme and are therefore multidisciplinary in nature. The main sectors and themes to be assessed are agriculture, water resources, forests, ecosystems, infrastructure and health. Key indicators and methods are summarized in the following tables.

Sensitivity of agriculture to climate and weather risks

Sensitivity of agriculture reflects how agricultural systems respond to changes in climate and weather patterns, considering both biophysical and socio-economic factors. Systematic assessment of agricultural sensitivity strengthens resilience to climate and weather extremes.
Key indicators	Examples	Methods
Crop and livestock yield variability	Sensitivity of staple crops (e.g., wheat, maize, rice) or livestock to extremes in temperature and precipitation	• Empirical Models: Regression or econometric models analyzing historical yield data against climatic variables (temperature, rainfall, extreme events). • Crop Simulation Models: Tools like DSSAT or APSIM to model crop growth under varying climate scenarios.
Soil health and fertility	Vulnerability of soil to erosion, salinity, or nutrient depletion due to climate change.	• Soil sampling and analysis for physical (erosion rates), chemical (nutrient levels), and biological properties (organic matter). • GIS-based mapping of areas prone to soil degradation or erosion under projected climate scenarios.
Water availability for agriculture	Dependence on rainfall, irrigation infrastructure, and vulnerability to droughts or floods.	• Analysis of irrigation efficiency and water use patterns. • Remote sensing and hydrological models (e.g., SWAT) to assess water resources under different climate conditions.
Susceptibility to pests and diseases	Increased vulnerability of crops or livestock to pests and diseases due to changing climate conditions.	• Monitoring pest/disease outbreaks and linking trends to climate variables. • Predictive models (e.g., CLIMEX) to assess shifts in pest and disease distributions under future climate scenarios.
Farming system	Smallholder farmers and traditional practices may be more sensitive to climate variability	• Household surveys to collect data on farm size, cropping patterns, and reliance on subsistence farming. • Sensitivity analysis of farming systems using socio-economic indicators.
Economic dependency on agriculture	Share of income derived from farming, and its sensitivity to climate shocks.	• National or regional economic data analysis to estimate agricultural GDP contribution and its fluctuation due to climate variability. • Household income surveys and market analysis.
Agro-biodiversity	Dependency on a narrow range of crops/varieties or livestock breeds increases sensitivity.	• Surveys and inventories of crop/livestock diversity. • Assessing the vulnerability of key species to climate variables using species distribution models

Sensitivity of water resources to climate and weather risks

Sensitivity of water resources is determined by how changes in variables such as precipitation, temperature, and extreme weather events affect the availability, quality, and management of water systems. Evaluating this sensitivity supports the development of targeted strategies for sustainable water management in a changing climate
Key indicators	Examples	Methods
Water availability and supply variability	Sensitivity of surface water (rivers, lakes) and groundwater to changes in rainfall and evaporation.	• Analysis of hydrographs to identify seasonal variations in water availability. • Hydrological modeling (e.g., SWAT, VIC) to simulate water flows and availability under varying climate conditions. • Analysis of long-term precipitation and runoff data to assess trends and variability.
Water quality	Sensitivity of water quality to increased temperatures, flooding, and pollutant loads.	• Sampling and testing of water for contaminants such as nutrients, pathogens, and heavy metals. • Predictive models linking water quality parameters (e.g., dissolved oxygen, turbidity) to climate drivers like temperature and flow changes.
Dependence on rainfed systems	Communities reliant on rainfed agriculture are more sensitive to climate variability.	• Surveys to determine reliance on rainfed water systems. • Analysis of regional rainfall patterns and their relationship to water-dependent activities.
Sensitivity of groundwater	Over-extraction and slow recharge rates make groundwater systems highly sensitive to climate stress.	• Monitoring of groundwater levels using piezometers or satellite-based tools like GRACE for large-scale groundwater changes. • Assessing recharge rates under different climate scenarios using hydrogeological models.
Ecological sensitivity of aquatic systems	Vulnerability of freshwater ecosystems (e.g., wetlands, rivers) to temperature and hydrological changes.	• Biodiversity assessments of aquatic species dependent on stable water conditions. • Modeling the flow-ecology relationship to identify thresholds for ecosystem health.

Sensitivity of forests to climate and weather risks

Sensitivity of forests refers to the response of forest ecosystems and their functions to climatic factors, including temperature, precipitation, and extreme weather events. It is shaped by ecological, physical, and socio-economic factors. Assessing forest sensitivity provides critical insights into vulnerabilities of this globally important ecosystem and the well-being of communities that depend on forests.
Key indicators	Examples	Methods
Forest health and productivity	Growth rates, tree mortality, and canopy health under changing climatic conditions.	Long-term monitoring of forest plots for growth and mortality rates. Use of remote sensing tools (e.g., NDVI, EVI) to assess vegetation health and productivity
Species composition and biodiversity	Forest sensitivity to shifts in species composition due to temperature or precipitation changes.	Biodiversity surveys to track changes in species richness and composition. Niche modeling (e.g., Maxent) to assess species distribution shifts under climate scenarios.
Pest and disease susceptibility	Increased vulnerability of forests to pests and pathogens under warming conditions.	Monitoring pest outbreaks and disease prevalence in forested areas. Predictive modeling of pest and pathogen spread under future climate scenarios.
Fire sensitivity	Increased forest vulnerability to wildfires due to higher temperatures and prolonged droughts.	Historical analysis of wildfire frequency and severity. Fire risk modeling based on fuel load, temperature, and moisture conditions (e.g., FlamMap).
Hydrological dependence	Sensitivity of forest ecosystems to changes in water availability and precipitation patterns.	Hydrological modeling to assess water availability for forested areas. Remote sensing of evapotranspiration and soil moisture.
Dependence on specific climatic ranges	Forests located at climatic extremes (e.g., tropical rainforests or boreal forests) are more sensitive to temperature and precipitation changes.	Climate-envelope modeling to identify the range of suitable conditions for key forest types. Spatial analysis of climate sensitivity zones using GIS tools.
Socio-economic importance	Dependence of local communities or industries on forest resources (e.g., timber, non-timber products).	Surveys and interviews to quantify reliance on forest resources. Economic analysis of forest-based livelihoods and their sensitivity to climate impacts

Sensitivity of ecosystems to climate and weather risks

Sensitivity of ecosystems depends on species composition, habitat conditions, ecological processes, and human interactions. Understanding ecosystem sensitivity is vital for safeguarding biodiversity, maintaining ecosystem services, and supporting adaptive management.
Key indicators	Examples	Methods
Species and biodiversity sensitivity	Species with narrow climatic tolerances, limited mobility, or specific habitat requirements are more sensitive	• Biodiversity surveys to measure species richness, abundance, and functional diversity. • Species distribution models (e.g., Maxent) to predict shifts in suitable habitats under climate scenarios.
Habitat condition and fragmentation	Ecosystems with degraded or fragmented habitats are more sensitive to additional climate stress	• Remote sensing and GIS mapping to assess habitat fragmentation and land-cover changes. • Ecological indices quantifying landscape connectivity or fragmentation.
Dependence on climate-regulated processes	Wetlands dependent on seasonal flooding or coral reefs sensitive to sea temperature	• Monitoring key ecological processes, such as water flow in wetlands or coral bleaching events. • Hydrological and oceanographic models to simulate climate impacts on ecosystem functions.
Soil and nutrient sensitivity	Sensitivity of ecosystems to soil degradation, nutrient cycling disruption, or changes in organic matter	• Soil sampling to measure nutrient levels, organic content, and erosion rates. • Coupling soil models (e.g., CENTURY) with climate variables to assess impacts.
Water dependency	Ecosystems like riparian zones or rainforests that rely on stable water availability are highly sensitive	• Hydrological modeling to assess water availability and variability. Remote sensing to monitor drought impacts (e.g., soil moisture, vegetation indices).
Susceptibility to extreme events	Sensitivity of ecosystems to floods, droughts, wildfires, or storms	• Analysis of historical data on extreme events and ecosystem responses. • Risk modeling to identify ecosystems at higher susceptibility to extreme events.
Dependence on external inputs or services	Managed ecosystems that rely on irrigation, pest control, or human maintenance	• Surveys and interviews to quantify reliance on external inputs. • System modeling to evaluate sensitivity under changing resource availability.

Sensitivity of infrastructure to climate and weather risks

Sensitivity of infrastructure reflects how changes in climate variables, such as temperature, precipitation, and extreme weather events, impact infrastructure performance, functionality, and longevity. Factors such as design, location, materials, usage, and maintenance play a key role. Assessing infrastructure sensitivity is essential for creating resilient systems capable of withstanding future climatic challenges.
Key indicators	Examples	Methods
Structural integrity and design	Sensitivity of buildings, bridges, and roads to temperature extremes, heavy precipitation, or high winds.	• Engineering assessments of structural materials and design thresholds (e.g., thermal expansion, wind resistance). • Stress testing and simulations of infrastructure under projected climate scenarios.
Exposure to extreme weather events	Sensitivity of coastal infrastructure to storm surges or urban infrastructure to heatwaves.	• Historical data analysis of damage caused by extreme weather (e.g., flood levels, wind speeds). • Scenario-based modeling to estimate impacts of extreme events on infrastructure.
Age and maintenance status	Older or poorly maintained infrastructure is more sensitive to climate impacts.	Surveys and inspections to assess the condition and remaining lifespan of infrastructure, including analysis of maintenance schedules and repair records to identify vulnerabilities.
Dependency on climate-sensitive systems	Infrastructure dependent on water resources (e.g., hydroelectric dams) or solar/wind-dependent energy grids.	• Hydrological and energy system assessments to determine climate sensitivity. • System modeling to analyze dependencies and cascading effects of climate impacts.
Location-specific sensitivity	Infrastructure in floodplains, coastal zones, or permafrost regions is more sensitive to climate changes.	• GIS mapping to overlay infrastructure locations with climate-sensitive zones (e.g., flood zones, erosion-prone areas). • Remote sensing to monitor environmental changes affecting infrastructure (e.g., coastal erosion).
Material sensitivity	Sensitivity of construction materials (e.g., asphalt, concrete, steel) to heat, moisture, or freeze-thaw cycles.	• Laboratory testing of materials under varying climate conditions. • Thermal and moisture sensitivity analysis using material performance models.
Urban heat island (UHI) effects	Urban infrastructure is sensitive to amplified heat in densely populated areas.	• Satellite-based thermal imaging to assess UHI effects. • Temperature monitoring within urban areas to analyze heat sensitivity.

Sensitivity of health to climate and weather risks

Assessing sensitivity of health in this context involves identifying factors that influence how susceptible populations are to climate-related health outcomes.
Key indicators	Examples	Methods
Prevalence of climate-sensitive diseases	Malaria, dengue, cholera, heat stress, respiratory illnesses	• Epidemiological studies to track incidence and prevalence rates in relation to climate variables (e.g., temperature, precipitation). • Correlation analysis between disease outbreaks and climate events.
Population health status	Rates of malnutrition, pre-existing chronic illnesses, immune-compromised individuals	• Health surveys to measure the prevalence of conditions exacerbated by climate variability. • Analysis of hospital admissions or health service utilization during climate-related events (e.g., heatwaves).
Access to healthcare	Availability of clinics, hospitals, and medical staff during climate extremes	• Geospatial mapping of healthcare facilities relative to climate-vulnerable areas. • Accessibility surveys (e.g., travel time, costs, infrastructure reliability).
Nutrition and food security	Dietary deficiencies linked to agricultural disruptions caused by climate variability.	• Household surveys assessing dietary diversity and caloric intake. • Statistical models linking crop yields, food prices, and nutrition outcomes to climate data.
Water and sanitation conditions	Exposure to waterborne diseases due to floods	• Assessment of water quality and availability during extreme events. • Surveys measuring reliance on unimproved water sources and sanitation facilities.
Demographic vulnerability	Proportion of persons physiologically more sensitive to climate-related health risks (children, elderly, and pregnant women).	• Demographic analysis using census data or household surveys. • Studies on differential mortality or morbidity rates during climate events.