| Similarity | Rank | |
|---|---|---|
| ozone | 0.807 | 5037 |
| anthropogenic | 0.783 | 51620 |
| acidification | 0.780 | 21870 |
| stratospheric | 0.780 | 25293 |
| organochlorine | 0.774 | 48475 |
| eutrophication | 0.771 | 42648 |
| tropospheric | 0.770 | 67421 |
| carcinogen | 0.762 | 23531 |
| nox | 0.759 | 28969 |
| caesium-137 | 0.758 | 59747 |
| deforestation | 0.753 | 16781 |
| malathion | 0.751 | 55530 |
| salinisation | 0.749 | 55212 |
| vocs | 0.747 | 67555 |
| desertification | 0.747 | 27119 |
| uv-b | 0.746 | 63631 |
| phytoplankton | 0.744 | 28965 |
| pollutant | 0.744 | 10281 |
| photochemical | 0.741 | 30345 |
| salinity | 0.739 | 22106 |
| nitrate | 0.735 | 7756 |
| overgrazing | 0.733 | 43790 |
| contaminant | 0.731 | 23773 |
| polonium-210 | 0.730 | 71984 |
| overfishing | 0.729 | 60336 |