What distinguishes a checklist screening methodology from a threshold screening methodology?

The key distinction between a checklist screening methodology and a threshold screening methodology lies in how they determine the need for an EIA. A checklist screening methodology uses a list of pre-defined criteria or questions to assess the potential environmental impacts of a project. These checklists typically cover a range of environmental issues, such as air and water quality, biodiversity, and social impacts. If the project triggers one or more items on the checklist, an EIA is usually required. The checklist approach is often qualitative, relying on expert judgment to determine whether the project is likely to have significant impacts. A threshold screening methodology, on the other hand, relies on specific quantitative thresholds or criteria to determine the need for an EIA. These thresholds might be based on project size, location, or the quantity of pollutants emitted. If the project exceeds one or more of these thresholds, an EIA is required. For example, a threshold might specify that an EIA is required for any project that involves clearing more than a certain number of hectares of forest or that emits more than a certain amount of air pollutants. The threshold approach is more objective and less reliant on subjective judgment than the checklist approach. A checklist would ask 'Does the project affect a protected area?' while a threshold method might state 'EIA is required if project is within 5km of a protected area'.