Definition and principle
Cumulative effects or impacts are any type of impact coming from an accumulation of direct or indirect significant or insignificant impacts of any type coming from a single project or multiple projects. Cumulative impacts are the result of complex interactions between biodiversity and the landscape, and this includes interactions with transport infrastructure. Such complexity renders a cumulative impact difficult to estimate and leads to an additional, operational challenge to distinguish ‘who is responsible for what?’ when considering multiple projects with major implementation differences.
Cumulative impact assessment and the management of cumulative impacts is currently not fully developed and requires further research, development, and innovation to improve its application. Nevertheless, key elements to perform relevant cumulative impact assessments, are outlined in dedicated guidelines such as the ‘Guidelines for the Assessment of Indirect and Cumulative Impact as well as Impact Interactions’ or the ‘Cumulative Impact Assessment and Management: Guidance for the Private Sector in Emerging Markets’.