There is growing evidence that current levels of pressures and human activities cause adverse effects on marine ecosystem. This report has compiled information from previous summaries and made supporting analyses to bring this evidence to a single report.
Management of human activities impacting the marine environment could follow a tiered approach, where:
areas of high cumulative impacts in CIAs are hot spots for management (e.g. HELCOM)
spatio-temporal characteristics of the pressures in the area are estimated (e.g. acute and spatially limited, long-lasting and widespread; see
Table 1),
severity of the activity is assessed in relation to other activities (e.g.
Figure 2),
known change points for impacts are assessed (e.g.
Figures 3 and
4 and summaries in this report),
impact distances are noted (see
Table 2).
It may be possible to observe thresholds or change points in ecosystem responses to specific adverse effects of human activities. Using these to determine “safe levels” or “sustainable levels” of human activities is not straightforward since they are associated with great uncertainty, arising from variation in local conditions and in the recipient ecosystem components. Hence, setting a “safe” level for an activity depends on how much risk one is willing to accept.