Oceans and Climate Change


By Ananya Chaturvedi

15th November 2021

Why are Oceans Important?

The ocean has a tremendous influence on the environment of our world. The ocean covers around 70% of the Earth's surface. According to the National Ocean Service, the ocean creates half of the world's oxygen and absorbs 50 times more carbon dioxide than our atmosphere. It also transfers heat from the equator to the poles, controlling our temperature and weather patterns. It's not surprising that it has a big influence on the Earth's ecology as nothing more than a consequence.


If the ocean did not exist, the Earth would be far hotter than it is now. This is due to the fact that water absorbs solar heat and disperses it more evenly throughout our planet.


Water in the ocean absorbs energy (heat) when the Earth warms and distributes it more evenly throughout the globe. Carbon dioxide from the atmosphere is also absorbed by the water. The increased heat and carbon dioxide in the water can change the environment for the many plants and animals that live there. Numerous fish, animals, plants, birds, and other species call the ocean home and rely on it for nourishment.


What is the issue?

Changes in ocean systems often occur over far longer time scales than changes in the atmosphere, where storms can arise and dissipate in a single day. Interactions between the seas and the atmosphere take months to years, as does water movement within the oceans, including the mixing of deep and shallow waters. As a result, trends can last for decades, centuries, or even millennia. As a result, even if greenhouse gas emissions were to be stabilized tomorrow, it would take many more years, decades to centuries, for the seas to respond to already-occurring changes in the atmosphere and climate.


As greenhouse gases capture more energy from the sun, the seas absorb more heat, leading to higher sea surface temperatures and increasing sea level. Changes in ocean temperatures and currents caused by climate change will cause changes in climatic patterns all across the planet. Warmer seas, for example, may stimulate the formation of stronger storms in the tropics, which can inflict property damage and loss of life. Coastal towns are particularly vulnerable to the effects of rising sea levels and greater storm surges.

Although the oceans assist to mitigate climate change by storing enormous amounts of carbon dioxide, rising dissolved carbon levels are altering the chemistry of saltwater and making it more acidic. Certain species, such as corals and shellfish, find it more difficult to construct their skeletons and shells when ocean acidification increases. These impacts, in turn, have the potential to significantly alter the biodiversity and productivity of ocean ecosystems.

The negative consequences that we have already begun to notice:

The ocean and coastlines provide important ecological services such as carbon storage, oxygen creation, food production, and revenue generation. Coastal habitats such as mangroves, salt marshes, and seagrass beds are critical for carbon storage and sequestration. They store carbon quicker and more efficiently per unit of area than terrestrial forests. Massive volumes of CO2 — an estimated 0.15-1.02 billion tons per year – are released into the atmosphere or ocean when these ecosystems are degraded, destroyed, or transformed, accounting for up to 19% of global carbon emissions through deforestation. They also lose the ecological services they provide, such as flood and storm protection.


The deterioration of coastal and marine habitats endangers the physical, economic, and food security of coastal populations, which account for around 40% of the global population. Climate change is already having an impact on local fishermen, indigenous and other coastal populations, multinational commercial organizations, and the tourist sector, notably in Small Island Developing States and many Least Developed Countries.


Weakening or even loss of ecosystems increases human vulnerability to climate change and undermines nations' ability to undertake climate change adaptation and catastrophe risk reduction strategies, such as those included in Nationally Determined Contributions.


Ocean warming and acidification are already having an impact on coastal and marine organisms and habitats, present levels of Carbon dioxide in the atmosphere are already too high for coral reefs to flourish, putting food provision, flood protection, and other functions provided by corals at danger. Furthermore, increasing GHG emissions worsen the impact of pre-existing stresses on coastal and marine ecosystems caused by land-based activities and the unsustainable use of these systems (e.g. overfishing, deep-sea mining and coastal development). These cumulative effects reduce the ocean's and coastlines' capacity to provide important ecological services.


Climate change is already affecting half of the world's oceans and by 2030, with devastating implications for marine life. Because warmer water temperatures mean less oxygen in the ocean, many creatures will be unable to survive in their existing habitats and will be forced to move. The oceans are a vital part of the Earth's ecology, providing biodiversity, food, and life. Over 40% of the world's population lives within 100 kilometers of the shore,  as a result, better ocean resource management is critical to maintaining global food security.