Environmental sensitivity atlases are tools that display relative sensitivity of areas to any given pressure. There have been a range of approaches developed for different geographies and sectors, capturing aspects of the importance of a predicted impact upon environmental assets.  Atlases are used to screen areas for development, support the Environmental Impact Assessment (EIA) process or respond to incidents. The goal is to help decision-makers understand where vulnerable assets are located and where to plan industrial operations in order to minimise the environmental and social risk.   In general, the development of an environmental sensitivity atlas should follow the procedure outlined in Figure 1, however each step can be adapted to the local context based on the intended use of the atlas, stakeholders’ values, drivers of change, data availability and the technical capacity of the users.

MESA (Mapping Environmentally Sensitive Assets) is a tool intended for a broad audience of individuals working on the development and use of environmental sensitivity maps in various contexts. It provides a step-by-step protocol for developing an environmental sensitivity atlas based on a standardised methodology that was developed following a review of multiple existing methods. This protocol is combined with an FME-based tool for the processing of environmental data and QGIS for visualising the final atlas. It can be applied for a variety of intended uses (e.g. strategic planning, project management and emergency response) and includes context-specific considerations to be made during the mapping process. Its key purpose is to support environmental management of the oil & gas sector, which is referred to throughout, but it is equally applicable to other sectors.

The document was originally developed to support a regional environmental sensitivity mapping workshop in Arusha (Tanzania), in September 2019, under the Oil for Development programme.