Seascape Management- At a Glance
Coastal communities are vulnerable to environmental and coastal hazards and impacts of climate change. For example, a recent study reveals that mangrove habitats are declining at a rate of 0.66% per year. This trend is 3–4 times faster than global forest loss. Similarly, some 75% of the world's coral reefs are rated as threatened and 85% of oyster reefs have been lost globally. Stakeholders – including local, regional, and global actors worry about climate change impacts across all coastal ecosystems.
Sea level rise leads to coastal erosion, inundations, storm floods, tidal waters encroachment into estuaries and river systems, contamination of freshwater reserves and food crops, loss of nesting beaches, as well as displacement of coastal lowlands and wetlands. Sea level rise poses a significant risk to coastal regions and communities, contributing to a restructuring of coastal ecosystems with implications for ocean circulation, biogeochemical cycling and fishery yields.
Despite myriad coastal zone challenges, integrated coastal zone management (ICZM) offers a multi-stakeholder partnership approach and an ecosystem-based adaptation strategies for addressing coastal risk and building coastal community and ecosystem resilience. For example, coastal ecosystems such as mangroves and seagrass can provide protection and adaptation. Investing in nature-based or ecosystem-based adaptation (EbA) like mangrove restoration will promote both ICZM and integrated water resources management (IWRM). Coastal EbA supports coastal zone management and water resources conservation by reducing floods and coastal erosion, increasing infiltration rates for recharging groundwater aquifers, improving water quality downstream, reducing sediment export into the water bodies, preventing marine pollution, and avoiding water impairment for drinking and swimming. According to research findings from the World Bank’s EPIC Response framework on innovative governance on floods and droughts , ICZM is “fundamentally intertwined with marine spatial planning by virtue of common geomorphological dynamics and the ecosystems providing services (such as flood protection) and goods to coastal economies”.
The ocean twilight zone is poorly understood, but research is now indicating that it will significantly impact carbon sequestration and fisheries. The twilight zone is 200-1,000 meters, where light can reach 1,000 meters, but an insignificant level of light goes past 200 meters below the surface. Scientists previously disregarded this zone; however, researchers believe there may be ten times if not a hundred times more biomass than initially estimated. The twilight zone is also an area where there is the largest animal migration as plankton and fish travel up to the surface. The ecosystem is thought to have a substantial role in carbon sequestration, removing 2 to 6 billion metric tons of carbon annually, which is greater than the global annual emission of vehicles (roughly 3.6 billion tons of carbon dioxide).
Share of Carribean Coral with Acropora
Number of coral bleaching events
Coastal communities are economic drivers, but face risk from climate change and environmental degradation . Coastal communities are home to 60 percent of the world’s population , as well as crucial economic resources and priceless ecosystems. The climate crisis coastal communities face is multiplying. As nations continue to expand their blue economies, coastal zone management will become more critical. The coastal zone is a rich and distinctive environment on which animals depend for migration, breeding, feeding, and protection, while mangroves absorb nutrients from river flow. In addition, humans rely on the coast for fishing, commerce, energy, agriculture, and transportation. Seventy-four percent of the population is projected to reside within 50 kilometers of the shore. Furthermore, 47.9 percent of the coastal region has been subjected to elevated levels of human pressure, with eighty-four percent of nations' coastal areas degraded by more than half. The cumulative effect is that certain coastal ecosystems have been seriously harmed and may never recover.
Upstream watersheds are the primary source and important drivers of pollution in coastal areas. Recent studies through modelling estimate that more than 1,000 rivers account for 80% of global annual emissions, which range between 0.8 million to 2.7 million metric tons per year, with small urban rivers among the most polluting. However, it remains understudied, specifically in parts of the world where these water bodies contribute the most the global ocean plastic pollution.
The increasing impacts of climate change on coastal ecosystems is already disrupting and changing the coast and increasing risks to people and infrastructure in coastal areas. To mitigate this risk, there is a need to adapt through measures such as nature-based solutions and providing more sustainable, cost-effective, and climate-resilient alternatives to existing infrastructure. For example, a floodable park may be a solution to replace grey infrastructure sea walls.
The term “blue carbon” refers to the carbon stored in coastal and marine ecosystems. The ecosystems are made of mangroves, seagrasses, tidal and salt marshes, which make highly productive coastal ecosystems that are particularly important for their capacity to store carbon within the plants and in the sediments below. Scientific assessments show that they can sequester two to four times more carbon than terrestrial forests and are thereby considered a key component of nature-based solutions to climate change.
Often, the mitigation efforts on climate change are focused on terrestrial ecosystems. This is not doing justice to the tremendous potential of “Blue” ecosystems in sequestering carbon. The “Blue Carbon” sequestration of mangroves, tidal marshes, and seagrass meadows can be more effective than forests at sequestering carbon. However, according to the Blue Carbon Initiative , about 340,000 to 980,000 hectares of these ecosystems are destroyed each year (resulting in 0.15 to 1.02 billion tons of CO2 released annually), with two thirds of the global historical mangrove coverage, over half of the tidal marshes, and a third of the seagrass meadows lost. Mangroves alone are estimated to be worth US$ 1.6 billion each year in ecosystem services that support coastal livelihoods and human populations globally.