Last ned - Direktoratet for naturforvaltning

Klimaendringer, havforsuring og langtransportert forurensning
Summary
This report is an assessment of the impacts of climate change, ocean acidification and long-range
pollution, and has been drawn up as part of the scientific basis for the preparation of an integrated
management plan for the North Sea and Skagerrak. Similar reports have been drawn up for fishing
and aquaculture, maritime transport, petroleum activities, renewable energy production (offshore
wind turbines) and land-based and coastal activities.
The North Sea and Skagerrak are under more pressure from human activities than other Norwegian
sea areas. There are large population centres in many of the surrounding countries, and the North
Sea–Skagerrak area itself shows the impacts of a high level of activity in many different sectors and
industries.
The report reviews current knowledge about pressures and impacts related to climate change, ocean
acidification and long-range pollution, and the effects these pressures may have on a predefined set
of ecosystem components. It also assesses the severity of these effects both at present and in the
future.
Two scenarios were developed for each of the three main themes of the report, one using positive
trends for most variables, and the other using mainly negative trends. The scenarios for long-range
pollution describe the expected situation in 2030, while the scenarios for climate change and ocean
acidification describe trends for the period 2050–2100. The scenarios have been used as a basis for
predicting effects on ecosystem components in the management plan area. There has been little
focus on assessing the current effects of climate change and ocean acidification, because it is so far
very difficult to distinguish between natural variations and more long-term trends.
Climate change
To provide a better basis for describing mechanisms through which climate change may result in
ecosystem change, 14 different pressures and impacts were identified. The report describes each of
these factors and assesses their effects on the different ecosystem components. The factors that are
considered to have the greatest potential for effects on ecosystem components are changes in ocean
temperature; changes in stratification, ocean circulation and current patterns; and changes in species
distribution. They are expected to have major effects in the management plan area in future, but the
level of uncertainty is very high for all three factors. The effects of the remaining pressures and
impacts are predicted to be moderate or minor. However, for alien species: increase in survival and
establishment, the effects are considered to be unknown, because they depend entirely on which
alien species become established in the management plan area. Climate change is likely to have a
wide range of impacts, and all the ecosystem components that have been assessed will be affected
to some extent.
Given the range of pressures and impacts associated with climate change and the fact that, even
considered alone, several of these are expected to have major effects, it is logical to conclude that
major cumulative effects are to be expected in the management plan area in the future.
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