| Abbreviation | Definition |
|---|---|
| ISTEC | Intertanko Safety Technical And Environmental Committee |
| ISWA | International Solid Waste Association |
| ITAP | International Transport of Air Pollutants |
| ITBC | Institute of Tropical Biology Conservation |
| ITEA | Institute of Tokyo Environmental Allergy |
| ITEC | Inter Tribal Environmental Council |
| ITEE | Information Technologies in Environmental Engineering |
| ITOP | Intercontinental Transport of Pollution |
| ITTO | International Tropical Timber Organization |
| ITWE | Integrated Total Warming Effects |
| IUCL | Intensive Use of Cultivated Land |
| IUED | Israel Union for Environmental Defense |
| IUFRO | International Union of Forest Research Organizations |
| IWEN | Irish Womens Environmental Network |
| IWGCBC | International Working Group on Coastal Blue Carbon |
| IWM | Integrated Waste Management |
| IWMS | Identified Wildlife Management Strategy |
| IWMS | Integrated Waste Management Solution |
| IWMS | Integrated Water Management System |
| IWMS | ISEM (Integrated Safety and Environmental Management) Work Management System |