Nature-based solutions (or nature-based systems, and abbreviated as NBS or NbS) is the sustainable management and use of natural processes to tackle socio-environmental issues. These issues include for example climate change mitigation and adaptation, water security, and disaster risk reduction. The aim is that resilient ecosystems (whether natural, managed, or newly created) provide solutions for the benefit of both societies and biodiversity. The 2019 UN Climate Action Summit highlighted nature-based solutions as an effective method to combat climate change. For example, nature-based systems for climate change adaptation can include natural flood management, restoring natural coastal defences, and providing local cooling.: 310  The concept of NBS is closely related to the concept of ecological engineering and ecosystem-based adaptation.: 284  Restoring mangroves along coastlines uses nature-based solutions to achieve several goals. Mangroves moderate the impact of waves and wind on coastal settlements or cities, and they sequester carbon. They also provide nursery zones for marine life which is important for sustaining fisheries. Additionally, mangrove forests can help to control coastal erosion resulting from sea level rise. Green roofs or walls (as part of green infrastructure) are also nature-based solutions that can be implemented in urban areas. They can reduce the effects of urban heat islands, capture stormwater, abate pollution, and act as carbon sinks. At the same time, they can enhance local biodiversity. Nature-based systems are more and more often forming a part of national and international policies on climate change. They are included in climate change policy, infrastructure investment, and climate finance mechanisms. The European Commission has been giving increasing attention to NBS since 2013. Yet, nature-based systems encounter numerous challenges during implementation. The IPCC pointed out that the term is "the subject of ongoing debate, with concerns that it may lead to the misunderstanding that NbS on its own can provide a global solution to climate change".: 24  To clarify this point further, the IPCC also stated that "nature-based systems cannot be regarded as an alternative to, or a reason to delay, deep cuts in GHG emissions".: 203  Source: Wikipedia (en)