Environmental Vulnerability Index

Environmental Vulnerability Index (EVI) for Gulf Coast counties

Synopsis of the EVI

The purpose of the Environmental Vulnerability Index (EVI) is to increase individual and community understanding of the susceptibility of harm to local ecosystems. Specifically, the index is used to assess the vulnerability of the environment itself to both human and natural hazards. This tool is at the national level, summarized by county, to make it applicable for local use. The EVI should be used by community planners as a tool to help shape decisions about how to make their regions more resilient. Concerned and empowered citizens can also use EVI information to lobby their local policymakers to provide mitigation and restoration strategies in their communities.

The EVI provides a snapshot of ecosystem conditions at the county level. This snapshot includes approximately 50 variables that evaluates the resiliency/vulnerability of a given county. To account for differences in county land area or population, each variable is standardized accordingly. Each variable value is then converted to a 'vulnerability scale' which represents the resiliency or vulnerability of that variable for a given county. The final EVI score for each county is the average of all 50 variables.

Raw Input Variables Used to Construct EVI

Variable Definition
High Winds Average annual excess wind over the last five years (summing speeds on days during which the maximum recorded wind speed is greated than 20% higher than the 30 year average maximum wind speed for that month) averaged over all reference climate stations.
Dry Periods Average annual rainfall deficit (mm) over the past 5 years for all months with more than 20% lower rainfall than the 30 year monthly average, averaged over all reference climate stations.
Wet Periods Average annual excess rainfall (mm) over the past 5 years for all months with more than 20% higher rainfall than the 30 year monthly average, averaged over all reference climate stations.
Hot Periods Average annual excess heat (degrees) over the past 5 years for all days more than 5*C (9*F) hotter than the 30 year mean monthly maximum, averaged over all reference climate stations.
Cold Periods Average annual heat deficit (degrees) over the past 5 years for all days more than 5*C (9*F) cooler than the 30 year mean monthly minimum, averaged over all reference climate stations.
Sea Temperatures Average annual deviation in Sea Surface Temperatures (SST) in the last 5 years in relation to the 30 year monthly means (1961-1990).
Volcanoes Cumulative volcano risk as the weighted number of volcanoes with the potential for eruption greater than or equal to a Volcanic Explosively Index of 2 (VEI 2) within 100km of he country land boundary (divided by the area of the land).
Earthquakes Cumulative earthquake energy within 100km of country land boundaries measured as Local Magnitude (ML) ≥ 6.0 and occuring at a depth of less than or equal to fifteen kilometres (≤15km depth) over 5 years (divided by land area).
Tsunamis Number of tsunamis or storms surges with runup greater than 2 metres above Mean High Water Spring tide (MHWS) per 1000 km coastline since 1900.
Slides Number of slides recorded in the last 5 years (EM-DAT defintions), divided by land area.
Land Area Total land area (km2).
Country Dispersion Ratio of length of borders (land and maritime) to total land area.
Isolation Distance to nearest continent (km).
Relief Altitude range (highest point subtracted from the lowest point in county).
Lowlands Percentage of land area less than or equal to 50m above sea level.
Borders Number of land and sea borders (including EEZ) shared with other counties.
Ecosystem Imbalance Weighted average change in trophic level since fisheries began (for trophic level slice ≤3.35).
Environmental Openness Average annual USD freight importants over the past 5 years by any means per km2 land area. (INDICATOR COULD CHANGE…)
Migrations Number of known species that migrate outside the territorial area at any time during their life spans (including land and all aquatic species) / area of land.
Endemics Number of known endemic species per million square kilometre land area. --Unique to that specific area!
Introductions Number of introduced species per 1000 kilometres of land area.
Endangered Species Number of endangered and vulnerable species per 1000 sq km land area (IUCN definitons).
Extinctions Number of species known to have become extinct since 1900 per 1000 sq km land area (IUCN definitions).
Vegetation Cover Percentage of natural and regrowth vegetation cover remaining (include forests, wetlands, prairies, tundra, desert and alpine associations).
Loss of Cover Net percentage change in natural vegetation cover over the last five years.
Habitat Fragmentation Total length of all roads in a country divided by land area.
Degradation Percent of land area that is either severely or very severely degraded (FAO / AGL Terrastat definitions).
Terrestrial Reserves Percent of terrestrial land area legally set aside as no take reserves.
Marine Reserves Percentage of continental shelf legally designated as marine protected areas (MPAs).
Intensive Farming Annual tonnage of intensively farmed animal products (includes aquaculture, cattle, pigs, poultry) produced over the last five years per square kilometre land area.
Fertilizers Average annual intensity of fertiliser use over the total land area over the last 5 years.
Pesticides Average annual pesticides used as km/km2/year over total land area over last 5 years.
Biotechnology Cumulative number of deliberate field trials of genetically modified organisms conducted in the country since 1986.
Productivity Overfishing Average ratio of productivity: fisheries catch over the last 5 years.
Fishing Effort Average annual number of fishers per kilometre of coastline over the last 5 years.
Renewable Water Average annual water usage as percentage of renewable water resources over the last 5 years.
SO2 Emissions Average annual SO2 emissions over the last 5 years.
Waste Production Average annual net amount of generated and imported toxic, hazardous and municipal wastes per square kilometre land area over the last 5 years.
Waste Treatment Mean annual percent of hazardous, toxic and municipal waste effectively managed and treated over the past 5 years.
Industry Average annual use of electricity for industry over the last 5 years per square kilometre of land. - polluting industries and consumption by industry
Spills Total number of spills of oil and hazardous substances greater than 1000 litres on land, in rivers or within territorial water per million km maritime coast during the last five years.
Mining Average annual mining production (include all surface and subsurface mining and quarrying) per km2 of land area over the past 5 years.
Sanitation Density of population without access to safe sanitation (WHO definitions).
Vehicles Number of vehicles per square kilometre of land area (most recent data).
Population Total human population density (number per km2 land area).
Population Growth Annual human population growth rate over the last 5 years.
Tourists Average annual number of international tourists per km2 land over the past 5 years.
Coastal Settlements Density of people living in coastal settlements (i.e. with a city centre within 100km of any maritime or lake coast).
Environmental Agreements Number of environmental treaties in force in a country.
Conflicts Average number of conflict years per decade within the country over the past 50 years.