Human Activities Thematic Assessment

Analysis of cumulative effects

Pressures can lead to changes in ecosystem state either singly or collectively (cumulative effects). The application of the ecosystem approach integrates conservation and management approaches in all of OSPAR’s work and helps to adapt the management of human activities to the complex and dynamic nature of marine ecosystems. To apply the ecosystem approach and to consider cumulative effects in thematic assessments requires an understanding of:

• the drivers of change [D]
• how human activities and pressures affect ecosystems [AP]
• the health, integrity and dynamics of marine ecosystems – baseline vs impacted state [S]
• the impact of changes on ecosystem goods and services [I]    
• integrated management measures (responses) [R]

In recognition of the connectivity and inter-relationships between these components OSPAR has developed a DAPSIR framework (Figure CE.1) to structure the thematic assessments.

Adapted from Elliott et al., (2017), application of the DAPSIR framework allows us to consider how multiple drivers (D) lead to multiple human activities (A) which exert multiple pressures (P) causing multiple changes in ecosystem state (S). These state changes have impacts (I) on multiple ecosystem services and the goods and benefits these provide to society which in turn influence the drivers of change. Management measures to prevent change or to mitigate the effects of change from these cumulative pressures are also incorporated into the assessment as responses (R). The section of this assessment on drivers describes some of the predominant drivers and the sections on activities, pressures and responses describe the predominant human activities, the associated pressures and management responses (DAPR). The section on impacts describes the work being progressed to incorporate the impact on ecosystem services (I) into the framework as well as OSPAR’s consideration of how to adopt natural capital accounting and the synergies with the DAPSIR framework.

The earlier subsection on renewable energy activities concludes that the scale of offshore wind installation in the OSPAR Maritime Area is expected to increase greatly in the next decade and beyond, primarily in the Greater North Sea and Celtic Seas. As such, renewable energy development (and in particular offshore wind) provides a useful case study for cumulative effects assessment (Figure CE.2).

The expansion of renewable energy will be associated with increases in construction activity (including piling) and turbine operation, as well as corresponding increases in shipping (construction, supply and maintenance vessel movements and operations); power cable laying and maintenance activities; and dredging and deposit operations associated with ground preparation and installation of offshore wind infrastructure. The range of pressures associated with these activities will also increase. OSPAR has a suite of indicators describing state change and these state changes can be influenced by pressures from offshore wind farm development (e.g,. impulsive noise; non-indigenous species; marine bird abundance; cetacean abundance and distribution; seal abundance and distribution; condition of benthic habitats). The outputs from these indicator assessments quantify such changes and these can be considered alongside the trends in human activities and pressures as part of a simplified cause and effect analysis. The overall objective is for OSPAR Contracting Parties to progress development to manage risks so as to avoid or minimise ‘unacceptable environmental impact from offshore wind activities’. A range of ecosystem services are impacted (positively and negatively) by offshore wind farm development and the type and extent of impact has consequences for the drivers. Consideration of the effectiveness of management measures is a critical part of the assessment of cumulative effects in terms of how impacts are prevented or mitigated. A single pathway of the DAPSIR connections for underwater noise from offshore wind farm development is shown in Figure CE.3. Quantifications will be added once available from each of the individual indicator and thematic assessments.

Figure CE.3 highlights the need for decision-makers to consider the negative environmental effects (e.g., underwater noise) and how these may be managed to reduce impacts (e.g., noise dampening) alongside the positive effects (e.g., mitigating the effects of climate change, renewable energy as alternatives to burning fossil fuels). This means there is a need to consider both the direct adverse effects on ecosystem status from offshore wind farm construction and operation and the adverse effects on the ecosystem if climate change effects are not abated. To ensure that society’s needs for energy are maintained, it may not be possible (or appropriate) to restrain the scale of offshore wind farm development in the North-East Atlantic. Instead, responses may need to focus on directing development to areas of lesser environmental sensitivity, developing and applying effective measures to mitigate adverse effects or applying compensation measures, such as habitat creation / restoration. This can only be achieved by applying a systemic approach to the assessment and management of the ecosystem, such as the DAPSIR being applied in the QSR 2023 to consider the collective pressures form human activities on ecosystem state.