HELCOM SPIA Tool#
Description#
Cumulative Effects Assessment (CEA)
CEA is the process of systematically analysing and assessing cumulative environmental change. The purpose of CEA is to ensure that the full range of consequences of actions is considered.
Cumulative impacts can occur over different temporal and spatial scales by interacting, combining and compounding so that the overall effect often exceeds the simple sum of previous effects.
The spatial scale can be local, regional or global, whilst the frequency or temporal scale includes past, present and future impacts on a specific environment or region. Cumulative effects can simply be defined as the total impact that a series of developments, either present, past or future, will have on the environment within a specific region over a particular period of time.
Source: DEAT (2004) Cumulative Effects Assessment, Integrated Environmental Management, Information Series 7, Department of Environmental Affairs and Tourism (DEAT), Pretoria.
HELCOM SPIA Tool
HELCOM SPIA tool enables the computation of spatial pressure and impact assessments utilizing the data layers employed in the HELCOM third holistic assessment (HOLAS 3) of the Baltic Sea. These data layers consist of 17 aggregated pressure layers and 57 ecosystem component layers. Users can perform pressure or impact calculations by utilizing all available data layers or by selecting specific combinations of layers.
The tool employs sensitivity scores derived from the HOLAS 3 SPIA assessment but also permits users to make edits to these scores. Within the tool, users can explore the available pressure and ecosystem component layers in the map viewer, access metadata descriptions, and modify sensitivity scores. Additionally, users can run pressure and impact calculations using input data and sensitivity scores of their choice, examine the results in the map viewer, including insights into the contribution of human activities, pressures, and ecosystem components to the impact, and download the result raster and statistics matrix. The tool encompasses the Spatial Impact Index (SII), which assesses the spatial distribution of cumulative effects in the Baltic Sea, taking into account sensitivity scores for pressure-ecosystem combinations.
The Baltic Sea Impact Index (BSII) quantifies holistic impact across all layers. The Spatial Pressure Index (SPI) calculates cumulative pressures from human activities in the Baltic Sea, leveraging aggregated pressure layers weighted by ecosystem component sensitivity scores to prevent overestimation of widespread, low-effect pressures. The Baltic Sea Pressure Index (BSPI) assesses cumulative pressure across all aggregated pressure layers.
Both the SII and SPI adhere to the concepts introduced by Halpern et al. (2008), calculating the sum of pressures or impacts in 1x1 km assessment units.