Science

What is the global coastal ocean?

The coastal ocean connecting the land and the open ocean is a region of immense societal, ecological and Earth System’s importance that is under unprecedented pressure from global climate and demographic change. The global coastal ocean is changing rapidly, both in terms of its environment and the vulnerability of adjacent coastal populations and infrastructure.

Why study it?

Global heating drives changes to temperature, stratification, circulation and oxygen content (alongside many other physicochemical properties). Increased dissolved inorganic carbon and hence ocean acidification (another consequence of increased atmospheric CO₂) impacts widely on marine ecology and ecosystem services.

Sea level rise is a robust outcome of anthropogenic climate change; global sea level has already risen by 20cm (1901–2018) and projected to rise by a further 28–101cm by 2100. Climate change impacts on extreme storms are less certain, however, the frequency of extreme storm surge events increases disproportionately with mean sea level rise. Human population is projected to rise to over 10 billion by 2100, with much of this growth concentrated in coastal mega-cities. Without careful adaptation measures this represents a substantial increase in vulnerability to coastal hazards. This population growth in turns grows the demand for marine resources and increases the potential for land-based pollution impacting the coastal ocean. For example, ~50% of human food production requires nitrogen-based fertilizer and ~50% of this ends up in the marine environment, leading to coastal eutrophication and hypoxia. Globally, almost 50% of coastal regions and marine protected areas are heavily impacted by human activities. Cities themselves are increasingly directly impinging on neighbouring coastal environments, and we now need to consider the urban ocean.

Understanding, predicting and developing solutions for these multiple impacts in the highly heterogenous coastal ocean environment is a substantial scientific challenge of global importance. It is projected that by 2030 the global marine and maritime economy will be worth $3 trillion. For example, about 80% of all tourism takes place in coastal areas and over 90% of fish catches come from the coastal ocean; ~950 million people rely on fisheries and mariculture for their main source of animal protein.

Coastal flooding impacts lives, livelihoods, food production and infrastructure; more than 600 million people live at less than 10m above sea level and it is projected that by 2100 between 176–287 million people may be exposed to episodic coastal flooding.

While coastal oceans are under immense pressure, they also provide part of the solution to managing and adapting to future change. Natural coastal habitats are regions of great biodiversity that can provide effective protection from coastal flooding (e.g. mangroves and salt marshes), sequester substantial quantities of carbon and mitigate land-based pollution. Below the seafloor, geological structures provide a resource for storing captured CO₂ to mitigate emissions during the energy transition away from fossil fuels.

What will FOCUS do?

In FOCUS we will bring to bear the full range of oceanographic tools to address the pressing challenges of the global coastal ocean. These tools include numerical models, satellite remote sensing, field surveys and laboratory work. Extensively we will reanalyse existing data from around the world in novel and innovative ways and we will engage with scientists from many regions (such as South and South East Asia and the Caribbean), to build on existing knowledge, in a spirit of mutual respect and transparency, freely sharing methods and data.

Work Packages