A. Why Oceans Matter
Earthrise was the first photograph to show our entire planet from beyond its own sky. Taken by astronaut William Anders during the Apollo 8 mission in December 1968, it revealed Earth as a blue sphere lifting above the grey horizon of the moon. A narrow band of sunlight traced the planet’s upper curve, and the rest floated against a backdrop of deep, unbroken black. Nature photographer Galen Rowell later called it “the most influential environmental photograph ever taken.” The image was captured almost by accident when Anders swung the camera toward the window. It offered a view that lasted only seconds, yet it reshaped how many people understood our place in the universe. It showed a world that was astonishingly small, improbably vibrant, and clearly alone.
From that vantage point, one truth stands out. Earth is blue. Its defining colour comes from the ocean, and without the ocean, our planet would bear little resemblance to the one we know. The chemical and thermal conditions that allowed early life to form around deep-sea vents would not have existed. The long arc of evolution that followed would not have unfolded. Every branch of life on this planet rests on the physical and chemical stability that seawater created long before there were continents or weather systems.
Seeing Earth as a blue sphere makes another truth impossible to ignore. The ocean does not sit beside life on Earth; it underwrites it. It may be picturesque, but it is more than a landscape. It is the operating system that makes our planet habitable. Its waters regulate temperature, give rise to oxygen, cycle nutrients, and move heat, carbon, and energy around the world in patterns that define the boundaries of what is possible on land. We live inside those boundaries every day, often without noticing them. We assume the climate will stay within the range our food systems can handle. We assume coastlines will remain stable. We assume storms will follow familiar patterns. We assume fisheries will replenish. We assume the world beneath our feet is steady.
All of those assumptions depend on systems that most people rarely contemplate. Earthrise made our planet look fragile because it is. That fragility is not poetic, but it is physical. And if we look closely enough, the ocean shows us that the conditions we depend on are beginning to shift.
Life emerged in the ocean long before the surface of the planet could support complex organisms. Early Earth was a place of intense heat, unstable atmosphere, and violent geological activity. In that environment, the first conditions that supported life existed only in the deep sea where mineral rich vents created natural laboratories of heat, chemistry, and energy. These settings allowed simple molecules to form, interact, and eventually assemble into the earliest living systems. Without the ocean’s buffering effect on temperature and its capacity to store and distribute energy, this early chemistry would not have unfolded in a way that led to anything more complex.
As the planet cooled and oceans expanded, they began shaping the atmosphere that still sustains us. Marine plants and plankton produced much of the oxygen that allowed life to move onto land. Over millions of years, ocean chemistry influenced the balance of gases in the air, slowly creating an environment that supported forests, mammals, and eventually human societies. The stability we now take for granted came from cycles that began in the sea and gradually extended outward.
The ocean also created the thermal and climatic conditions that human beings evolved within. Its capacity to absorb and move heat prevented the planet from swinging between extremes. Currents carried warm and cold water around the globe in patterns that shaped weather, rainfall, and the distribution of nutrients. These patterns set the boundaries within which food systems developed and where human settlements took root. Every harvest, every coastal port, and every stable growing season is linked to processes unfolding in seawater thousands of kilometres away.
This long history matters because it shows that the ocean is not simply one ecosystem among many. It is the original setting for life and the continuing regulator of the conditions that make life possible. The air we breathe, the food we grow, and the climate we live within are all tied to systems that formed in the ocean and continue to evolve through it. Understanding this foundation is essential for any discussion about ocean health today. It reminds us that changes in marine systems are not distant or abstract. They affect the physical structure of the world we inhabit and the stability that human beings have relied on for thousands of years.
The systems that support modern civilization are tied to the ocean in ways that remain largely invisible in daily life. The vast currents that move through the Atlantic, Pacific, and Indian Oceans act as global conveyors of heat. These flows regulate the temperature of continents, influence seasonal rainfall, and shape the patterns that allow agriculture to function. Regions that depend on predictable monsoons, steady trade winds, or temperate growing seasons rely on the stability of these currents.
Marine ecosystems also underpin food security for billions of people. Fisheries provide a major source of protein for many coastal and island nations, and entire economies depend on healthy fish populations and the habitats that sustain them. Coral reefs, mangroves, estuaries, and kelp forests act as nurseries for marine life. When these systems function as they should, they support livelihoods across fishing communities, processing industries, and global supply chains that reach far inland.
Coastal ecosystems provide more than food. They act as natural buffers that protect shorelines from erosion, storms, and rising seas. Mangroves and salt marshes absorb wave energy and store large amounts of carbon. Seagrass beds stabilize sediments and filter water. These habitats support biodiversity, but they also protect homes, ports, and infrastructure that sit close to the water. In many parts of the world, these natural systems serve as the first line of defense for cities, power grids, and transportation networks.
Trade, which is central to the global economy, also relies on ocean stability. Shipping routes cross the same waters that regulate climate and host marine life. Ports depend on predictable tides, steady sediment patterns, and navigable coastal conditions. Disruptions in ocean dynamics can affect everything from shipping safety to the timing of deliveries. The modern supply chain, which connects producers and consumers across continents, is inseparable from the physical behaviour of the ocean.
The ocean does not simply support civilization. It shapes the conditions that allow civilization to exist. Climate patterns, food systems, coastal protection, and global trade all depend on stable marine processes. When these processes shift, the consequences reach far beyond coastlines. They influence agricultural output, economic stability, and the safety of communities across the world. Understanding the ocean as a stabilizing force is essential to understanding why changes in marine systems are not distant environmental concerns. They are shifts in the foundation on which human societies rest.
The ocean has absorbed more change in the past century than at any point in human history. Since the beginning of the industrial revolution, greenhouse gas emissions have increased the amount of heat entering the Earth system, and the atmosphere can only absorb so much of it. The rest has moved into the ocean. Today, the ocean has taken in more than ninety percent of the excess heat added to the planet since the start of the industrial era. This has slowed the rate of warming on land, but it has also altered the basic conditions of marine environments.
Warming water expands, and this expansion combines with the melting of glaciers and ice sheets to raise sea levels. Together, these forces are reshaping coastlines and increasing the reach of storm surges. Shifts in temperature also influence the strength and direction of major current systems. Even small changes in circulation can affect rainfall, storm formation, and seasonal climate across entire regions. These changes alter growing conditions for agriculture, water availability for communities, and the broader patterns that food and energy systems depend on.
The chemistry of the ocean is changing at the same time. As more carbon dioxide enters seawater, the ocean becomes more acidic. This shift affects organisms that rely on calcium carbonate to build shells and skeletons, including corals, shellfish, and many forms of plankton. When these foundational species are stressed, the marine food web becomes less stable. Coral reefs bleach and die. Shellfish populations decline. The base of marine life, which supports fisheries across the world, becomes more fragile.
Species are responding to these pressures by moving into new areas in search of conditions they can tolerate. Some marine ecosystems can shift with them, but many cannot. As species move, the communities that depend on them face uncertainty in both harvest and income. Coastal economies built on predictable cycles of marine life are finding those cycles less reliable than they once were.
Natural buffers that protect coasts are also losing resilience. Mangroves are under pressure from rising seas and development. Seagrass beds struggle with warming waters and declining water quality. Kelp forests weaken under the combined effects of heat and invasive species. As these systems decline, the coasts they support become more exposed to erosion, flooding, and storm damage. The financial burden on households, businesses, and insurers increases as protective natural systems wear down, and infrastructure that once felt secure must now withstand greater environmental stress.
These changes originate in the ocean, but their influence extends deep into the structures that support modern life. Food production, trade routes, infrastructure planning, coastal safety, and economic stability all feel the effects. The conditions that have supported human societies for thousands of years are no longer guaranteed. The ocean, which once buffered the planet from extremes, now signals that its capacity to absorb additional pressure is reaching its limit.
The changes unfolding in the ocean create risks and pressures that no sector can ignore. They affect the security of food systems, the stability of coastlines, the reliability of trade routes, and the long term value of assets built along the water. These shifts also influence public finances, insurance markets, and the cost of protecting communities from rising seas and stronger storms. In this environment, the decisions made by lenders, investors, and policymakers carry real influence over how societies respond.
As the scale of ocean change becomes clearer, the work of finance takes on a broader significance. It remains grounded in risk, capital, and returns, but it also shapes how societies choose to respond. Many practitioners carry a sense of responsibility that extends beyond individual transactions. They want their skills to support outcomes that strengthen communities and ecosystems over time. That sense of purpose does not replace technical discipline. It reinforces it, and it encourages steadiness in decisions that affect long term resilience.
Finance shapes the way marine resources are used and how risks are understood. It determines which industries expand, which practices are rewarded, and which activities face limits. Capital flows influence whether damaged habitats are restored or left to decline. They also influence whether coastal infrastructure is designed for the world we have known or for the conditions that are emerging. When investment aligns with the health of marine systems, it can strengthen resilience. When it does not, it can increase vulnerability and accelerate loss.
These dynamics place finance inside the story of ocean change, not on the sidelines. They reveal that blue finance is not a product label or a niche category. It is the practice of aligning financial systems with the processes that make a stable world possible. It asks practitioners to understand the physical realities of the ocean and to recognize how their decisions affect those realities over time.
This book is written for people who carry some part of that responsibility. Lenders who need to evaluate exposure to coastal change. Investors who assess risk across shipping, fisheries, ports, and offshore energy. Policymakers who set the rules for marine development, conservation, and infrastructure. Development agencies and foundations that support coastal resilience. Scientists and researchers who interpret the signals coming from a fast changing ocean. Coastal communities and Indigenous Nations whose knowledge and stewardship remain essential to any lasting solution. These roles differ, yet all rely on the condition of the ocean and all influence it in return.
The chapters that follow explore these connections with a focus on clarity and practical value. They examine how shifting ocean conditions affect assets and liabilities, how governance structures shape incentives, and how financial instruments can support healthier and more resilient marine systems. The aim is to show how finance can help steward the largest living system on Earth and provide a foundation for sound decision making in a world where the stability of the ocean can no longer be assumed.
This essay will appear in the forthcoming book Blue Finance: Evolving Finance for a Living Ocean.