2 Coastal restoration: a priority for biodiversity, climate and policy
The relationship between humans and the natural world is not sustainable and has not been for a long time. Production and consumption continue at a pace faster than the resources we rely on can recover. The consequences of these actions are increasingly becoming apparent: the climate is changing at an unprecedented rate and species from the highest mountains to the deepest ocean are being lost. We are in a climate and biodiversity crisis and society is at crossroads. The decisions and actions taken now will have implications for the generations that follow.
The severity of the situation and the impetus for action are recognised across society. Governments, businesses and citizens are calling for a change in the status quo and an acceleration of solutions. Policies, frameworks and commitments at local, national, regional and international scales have been agreed in order to reduce and repair our impact on the natural world. The Sustainable Development Goals (SDGs) provide a blueprint for how we can transition to a more sustainable future, addressing global challenges, including poverty, inequality, climate change, environmental degradation, peace and justice, and specific frameworks and agreements exist and are being improved to combat biodiversity and climate risks. As several significant global frameworks commence, 2021 marks a âsuper yearâ and a pivotal time for people and nature. Under the Post-2020 Biodiversity Framework of the Convention on Biological Diversity (CBD), countries will agree to new global goals and targets to improve conservation of biodiversity and develop strategies for its sustainable use (Convention on Biological Diversity, 2020); the United Nations Framework Convention on Climate Change (UNFCCC) will hold the 26th Convention of the Parties to encourage greater commitments to reduce carbon emissions by 2030 (UNFCCC, 2015); and the UN Decade of Action (2021â2030) will support the acceleration of sustainable solutions to achieve the SDGs by 2030.
Transcending sectors, geographies and ecosystems, the above frameworks call for governments, the private sector, academia and civil society to undertake urgent actions to address societal challenges, including climate change and biodiversity loss. Within this context, it is important to note the contribution that nature has in terms of tackling these risks and how the climate change and biodiversity agendas of these global frameworks are therefore intrinsically linked. Human actions, such as habitat destruction and pollution, contribute to biodiversity loss and climate change, whilst a decrease in biodiversity can increase the vulnerability of local people and species to climate change impacts and result in further biodiversity loss. The close relationship between the challenges faced requires integrated solutions that provide benefits across the climate-biodiversity nexus.
Ecosystem restoration can provide such solutions. Commonly defined as the âprocess of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyedâ (SER Primer, 2004), restoration is increasingly seen as central to conserving biodiversity, stabilising the Earthâs climate and helping people and nature adapt to climate change impacts. For example, a global meta-analysis indicated that the restoration of degraded systems enhanced overall biodiversity by 44% and provided a range of benefits across degraded ecosystems (Benayas et al., 2009).
The momentum for ecosystem restoration has been growing steadily in recent years, including through the declaration of the UN Decade on Ecosystem Restoration 2021â2030 (A/RES/73/284), which seeks to upscale the restoration of damaged, degraded and destroyed ecosystems. The UN Decade on Ecosystem Restoration will accelerate the attainment of existing global restoration goals, such as the Bonn Challenge, which aims to restore 350 million hectares of degraded land by 2030 â an area almost the size of India. Through the Bonn Challenge, more than 70 pledgers from more than 60 countries have so far committed to bring over 210 million hectares of degraded and deforested lands under restoration. This endeavour builds on regional efforts such as the Initiative 20Ă20 in Latin America that aims to restore 20 million hectares of degraded land by 2020, and the AFR100 African Forest Landscape Restoration Initiative that aims to bring 100 million hectares of degraded land under restoration by 2030. Such international initiatives are, however, predominantly terrestrial. Despite the oceans covering 70% of the Earth and holding some of our most biodiverse ecosystems, some of which have greater climate mitigation potential than their terrestrial counterparts, international support for coastal and marine ecosystem restoration lags (Waltham et al., 2020). A target for marine and coastal ecosystems restoration is yet to be set for the UN Decade on Ecosystem Restoration (UNEP and FAO, 2020) and currently, the Global Mangrove Alliance is the only comparable global restoration initiative, aiming for a 20% increase in the global area of mangroves by 2030. Acknowledgement of this needs to accelerate global ocean science for sustainable development is demonstrated by declaration of the UN Decade of Ocean Science for Sustainable Development (A/RES/72/73) which will commence in 2021 alongside the UN Decade on Ecosystem Restoration.
2021 offers unparalleled opportunities to generate science and implement actions to conserve, restore and sustainably develop our oceans for the benefits of society, climate and biodiversity. In order to capitalise on the opportunities and deliver the intended benefits of the UN Decade on Ecosystem Restoration, it is vital to understand the current evidence and identify gaps and opportunities moving forward. With coastal ecosystems at the front line of biodiversity loss and climate change impacts, this chapter will explore coastal restoration in the context of safeguarding biodiversity and mitigating climate change.
We define seascape as the marine and coastal ecosystems â from shallow littoral ecosystems to deep-sea habitats, including the biodiversity above and below the water.
In the rest of this section, we explore the need for coastal restoration and the global policies that aim to address current biodiversity and climate crises through restoration. In Section 3, we will explore the underlying factors that are required to inform restoration actions of these global policies and the challenges we face within these components. Reflecting on these challenges, in Section 4, we propose several opportunities that could help bring together biodiversity and climate into coastal restoration action as we move into the super year and beyond.
3 The need for policy landscape relating to coastal restoration
Coastal habitats, including mangroves, seagrasses, saltmarshes and coral reefs are incredibly rich in life, providing homes, feeding grounds and nursery areas for numerous species (Hemminga and Duarte, 2000), whilst also acting as natural barriers against storm surges and helping prevent coastal erosion (HerkĂŒl and Kotta, 2009). Annually, mangroves, for example, protect more than 15 million people and reduce property damage by more than $US 65 billion (MenĂ©ndez et al., 2020). Healthy coastal ecosystems are also hugely effective carbon sinks, sequestering 20 times more carbon than terrestrial ecosystems. Annual estimations predict this to be as high as 30 million tonnes of carbon sequestration by mangroves, 80 million tonnes by saltmarshes and 100 million tonnes by seagrass meadows (National Academies of Sciences, Engineering, and Medicine, 2019).
However, it is estimated that we have lost over 85% of wetlands area between 1700 and 2000 (DĂaz et al., 2020). Habitat-specific estimates predict a 35% decline in seagrass meadows during the past 40 years (Waycott et al., 2009), a 50% decline in saltmarsh and mangroves (Burke et al., 2011; Valiela et al., 2001; Zedler and Kercher, 2005) and more than 85% loss of oyster reefs (Beck et al., 2011). Since the 1870s, more than 50% of live coral cover of warm-water corals has been lost (DĂaz et al., 2020) and currently 90% of warm-water coral reefs are threatened (Burke et al., 2011). Cumulatively, it is estimated that 66% of marine ecosystems are damaged, degraded or modified (DĂaz et al., 2020). The consequences of such large losses are already being felt at the species and genetic levels. Global losses, such as 36% loss of populations of coastal and marine species since 1970 (WWF, 2018), are linked to regional and local losses, such as the 50â80% loss of wetland in the Yellow Sea contributing to declining migratory bird populations in Asia (Larson, 2015).
With marine ecosystems particularly vulnerable to climate change (Gattuso et al., 2015; Pinsky et al., 2019), such losses are predicted to continue to increase (Harley et al., 2006). 70â90 percent of remaining corals are projected to decline when exposed to a temperature increase of 1.5 degrees Celsius (IPCC, 2018), with even greater losses predicted with more extreme levels of warming. These changes will undoubtedly lead to further declines in biodiversity and impacts upon society. Degradation of these habitats is estimated to release 0.15â1.02 billion tons of carbon dioxide into the atmosphere annually (Pendleton et al., 2012), and climate change impacts such as sea-level rise and storms pose an increased risk to small island developing states (Hay, 2013).
It is evident that we must take action to address the current climate and biodiversity crises in a sustainable manner, using tools that work for both people and nature. Nature-based solutions have been proposed as such an approach. Posed as a broad umbrella term, the Global Standard for Nature-based Solutions defines this as âactions to protect, sustainably manage, and restore natural or modified ecosystems, that address societal challenges effectively and adaptively, simultaneously providing human well-being and biodiversity benefitsâ. Within this, coastal restoration can therefore be classified as a nature-based solution â providing a means of adapting to and mitigating climate change in an efficient and integrated manner whilst also providing biodiversity benefits (Figure 2.1). Here it is important...
