Table 1. Summary of environmental vulnerability indices (EVIs) for Tobago. The types of EVI indicators include indicators of environmental risk (ERI), intrinsic resilience (IRI), and environmental degradation (EDI). The indicator subcategories include meteorological events (Met), geological events (G), country characteristics (CC), biological factors (B), and anthropogenic factors (A). The range is the range of units for the score obtained, and the unit is the unit of measurement. VEI stands for "volcano explosivity index," and MHWS for "mean high water spring."

EVI no.  
Type
 
Subcategory
 
Description
 
Score
 
Range
 
Unit
2  
REI
 
Met
  Number of days over the last 5 yr with a maximum wind speed > 20% higher than the average maximum for that month  
3
 
11–20
 
Days
3  
REI
 
Met
  Number of months over the last 5 yr with rainfall > 20% lower than the 30-yr average for that month  
4
 
16–20
 
Months
4  
REI
 
Met
  Number of months over the last 5 yr with rainfall > 20% higher than the 30-yr average for that month  
4
 
16–20
 
Months
5  
REI
 
Met
  Number of days over the last 5 yr with a temperature > 5°C higher than the mean monthly maximum for that month  
1
 
0–10
 
Months
6  
REI
 
Met
  Number of days over the last 5 yr with a temperature > 5°C lower than the mean monthly maximum for that month  
1
 
0–10
 
Days
7  
REI
 
G
  Number of volcanoes with potential for eruption ≥ VEI 4 within 100 km of country land boundary/area of land  
1
 
0
 
volcanoes/km2
8  
REI
 
G
  Earthquakes over the last 5 yr with magnitude ≥ 6.0 and depth ≥ 15 km  
2
 
0–1
 
earthquakes/km2
9  
REI
 
G
  Number of tsunamis or storm surges with a run-up > 2 m above MHWS/100 km coastline since 1900  
1
 
0
 
tsunamis/km2
10  
IRI
 
CC
  Total land area  
6
 
100–1000
 
km2
11  
IRI
 
CC
  Length of ocean shoreline or land border divided by total land area  
3
 
0.1–0.5
 
km/km2
12  
IRI
 
CC
  Distance to nearest continent within 10 degrees latitude  
2
 
> 0–500
 
Kilometers
13  
IRI
 
CC
  Altitude range  
5
 
101–1000
 
Meters
14  
IRI
 
CC
  Percent of land area < 10 m above sea level  
5
 
5.1–10
 
%
16  
IRI
 
CC
  Number of known endemic species  
4
 
31–50
 
spp./km2
17  
REI
 
B
  Number of reported and verified organism outbreaks over last 5 yr per square kilometer of land area  
3
 
11–30
 
outbreaks/km2
18  
REI
 
B
  Total tonnage of freight imported per year per square kilometer of land area  
4
 
201–300
 
t • km-2 • yr-1
19  
REI
 
B
  Number of introduced species per square kilometer of land area since 1900  
2
 
> 0–100
 
spp./km2
22  
REI
 
B
  Percentage of natural and regrowth vegetation remaining  
3
 
41–60
 
%
23  
REI
 
B
  Tonnage of intensively farmed animal product per square kilometer of land area per year  
2
 
> 0–1
 
t • km-2 • yr-1
24  
REI
 
B
  Percentage of fisheries stocks overfished  
3
 
> 0–20
 
%
25  
EDI
 
A
  Density of people living in coastal settlements with a city center within 20 km of the coast  
7
 
> 200
 
persons/km2
26  
REI
 
A
  Total human population density  
6
 
101–200
 
persons/km2
27  
REI
 
A
  Annual population growth rate averaged over the last 5 yr  
4
 
0.51–1
 
%
28  
REI
 
A
  Net percentage of land area changed by removal of natural vegetation during the last 5 yr  
7
 
> 5
 
%
29  
REI
 
A
  Annual number of international tourists times average days stayed divided by 365 divided by square kilometers  
1
 
0–10
 
persons • km-2 • d-1
30  
REI
 
A
  Litres of untreated industrial and domestic wastewater discharged per square kilometer of land area per day  
5
 
4001–6000
 
l • km-2 • d-1
31  
REI
 
A
  Total tonnage of generated and net imported toxic, hazardous, and municipal waste per square kilometer of land area per year  
6
 
51–60
 
t • km-2 • yr-1
33  
REI
 
A
  Number of spills of oil and hazardous substances > 1000 L during the last 5 yr on land, in rivers, or within territorial waters divided by land area (*1000)  
1
 
0
 
spills/km2
34  
REI
 
A
  Number of nuclear, chemical, and other major industrial facilities that would cause significant damage  
1
 
0
 
facilities/km2
35  
REI
 
A
  Number of vehicles  
1
 
0–5
 
vehicles/km2
36  
REI
 
A
  Maximum 24-hr sulfur dioxide concentration  
1
 
...
 
µg/m3
37  
REI
 
A
  Metric tons of NPK fertilizers used per square kilometer of agricultural land area per year (*1000)  
1
 
0–20
 
t • km-2 • yr-1
38  
REI
 
A
  Metric tons of pesticides and fertilizers used per square kilometer of agricultural land area per year (*1000)  
3
 
41–60
 
t • km-2 • yr-1
40  
REI
 
A
  Percentage of land area degraded since 1950  
7
 
> 10
 
%
41  
REI
 
A
  Mean rate of water usage per capita per day  
7
 
> 200
 
t • person-1 • d-1
43  
REI
 
A
  Percentage of land area affected by mining and quarrying  
2
 
> 0–1
 
%
44  
REI
 
A
  Percentage of terrestrial zone set aside as reserves  
2
 
11–20
 
%
45  
REI
 
A
  Percentage of marine zone set aside as reserves  
5
 
0.5–1
 
%
46  
REI
 
A
  Number of wars or civil uprisings over the last 50 yr within the territory  
1
 
0
 
Years
47  
REI
 
A
  Percentage of population with access to safe sanitation  
1
 
No levels
 
No units