Marine and coastal ecosystems are invaluable as they provide important resources and services to humanity. In particular, the storage of CO₂ in intact coastal and marine ecosystems play an important role as they contribute to climate change mitigation and provide major adaptation benefits. Nevertheless, human activities such as overfishing, pollution, and the effects of climate change are causing significant degradation of these ecosystems.

This policy paper addresses the restoration of marine and coastal ecosystems. There is a great need for their restoration, but so far there has been comparatively little political attention and implementation of restoration measures. The UN Decades of Ecosystem Restoration and Ocean Science for Sustainable Development are highlighted as important platforms that can support needed changes and contribute to the achievement of UN Sustainable Development Goal 14. This goal seeks to conserve the oceans and marine resources. The new Global Biodiversity Framework (GBF) of the Convention on Biological Diversity (CBD) is seen as an ambitious step, if strengthened and mainstreamed into national strategies. It includes specific targets for ecosystem restoration under "Goal A Target 2." If implemented ambitiously (as the Aichi Targets of the previous GBF were largely not met and another failure must be avoided), these could result in significant improvement of marine and coastal ecosystems. Restoration of marine and coastal ecosystems needs to be.

The policy paper argues for synergies among UN decades and highlights the need to integrate different approaches to restoring marine and coastal ecosystems. The "ridge to reef" approach, which considers the interplay of land and marine systems, and the development of "seascape" approaches to ecosystem identification and restoration, are of particular importance. The paper calls for increased financial support for large-scale projects and research in marine ecosystem restoration. It also stresses the need to consistently implement regional legal mechanisms such as the EU's proposed regulation on nature restoration (NRL) and to adopt them in other regions. The NRL legally binding targets, including for nature restoration on 20% of the EU's land and marine areas by 2030 and for restoration of all ecosystems by 2050, but again its impact will depend on an effective national implementation by Member Stats. In the face of accelerated climate change, the development of integrated approaches and adaptive management plans is recommended. Multidisciplinary and cross-sectoral collaboration, e.g., in implementing GBF targets at the national level, can help improve resilience and sustainable management of marine and coastal ecosystems. Reducing overfishing and its harmful impacts and improving enforcement capacity are identified as fundamental requirements for this.