What is Ocean Warming?
Water is arguably the most important element on earth; it sets us apart from the rest of the solar system and sustains all life forms. Around 71% of the Earth is water-covered, with the ocean providing 95.5% of all of the Earth’s water. (USGS) Water is also frozen in glaciers, trapped in the air around us, and make up most of the human body. We depend on water every day for hydration, bathing, transportation, food, and even employment. When you think of climate change, you are likely to think of the effects on land, but there are impacts on marine life. Marine life and habitats are crucial for the earth; they comprise about 50% of global primary production and support extensive biodiversity. (Schneider & Mastrandrea, 2010) Oceans and other water sources are altering as glaciers melt, the water rises, and the Earth warms.
Ocean warming is caused by the increase in atmospheric carbon, which causes warming sea temperatures and alterations in our oceans’ chemical composition. This is a major problem for several reasons, and the destruction of marine life will only add to climate change. Oceans provide the second-largest carbon reservoir, which is around twenty and fifty times greater than those in the terrestrial biosphere or the atmosphere. The world’s oceans currently absorb, on average, about 1 metric ton of the CO2 produced by each person every year. (Schneider & Mastrandrea) Since the early 1800s, our oceans have buffered atmospheric climate change effects, causing a completely different but alarming product. Carbon dioxide reacts with seawater and forms carbonic acid, making the water more acidic; this is called ocean acidification. This process changes the water's pH level, with researchers claiming that the pH has dropped by about 0.1 unit since preindustrial times. Ocean pH could potentially fall as much as 0.4 units by 2100 and 0.7 units by 2300. Ocean pH will take around 10,000 years to return to preindustrial levels. (Schneider & Mastrandrea) A change in pH will cause numerous shell-producing and low lying species to become extinct. This is a major concern for marine scientists because bottom-dwelling species make up a vital part of the marine ecosystems.
Ocean warming will also cause a major loss in marine biodiversity, setting off a chain reaction within the entire food system. Once the water reaches a certain temperature and pH, entire species will have to learn to adjust to warmer weather, move to an ideal climate, or slowly go extinct. There are already strong signs of warming oceans, with one example being the decreasing population of codfish. According to marine scientists, reduced survival of young cod in the North Sea may be due to the increase in the sea surface temperature of around 1 degree Celsius. (Schneider & Mastrandrea). The loss of marine biodiversity has also led to unsustainable coral habitats. Coral bleaching happens when corals are stressed by changes in conditions such as temperature, light, or nutrients. The coral expels the symbiotic algae living in their tissues, causing them to turn completely white. (NOAA) Coral serves as a home to numerous fish and sea creatures, and without it, many species will have to find a new habitat.
Global warming and rising sea levels have led to ocean deserts or large unproductive waters in the mid-ocean. The melting of glaciers has caused thermohaline circulation, where large ocean currents carry heat around the ocean. Deep-ocean currents are driven by differences in the water’s density controlled by temperature (thermo) and salinity (haline). (NOAA). One example of this is Atlantic Heat Conveyor, which maintains mild temperatures in northwestern Europe and its seas. Researchers have observations to suggest that it is losing its strength. Ocean desserts will strongly affect the fishing profit in the sed area, causing a possible loss of protein for an entire region.
Ocean warming and acidification, and marine biodiversity loss are a few of the unfortunate side effects of climate change. As scientists continue to study the effects a warmer sea has on the animals, climate, and overall ecosystem, it is uncertain how much will change. However, it is clear that the oceans we know, love, and rely on are changing. If rising temperatures and sea levels continue to rise, there will be major impacts on those who live on the water and depend on its bounty for sustenance.
References
Schneider, S., Rosencranz, A., Mastrandrea, M., Kuntz-Duriseti, K. (2010). Climate Change Science and Policy. Island Press. Washington.
National Oceanic and Atmospheric Administration (NOAA). (2020). Thermohaline Circulation. Retrieved from https://oceanservice.noaa.gov/education/tutorial_currents/05conveyor1.html
National Oceanic and Atmospheric Administration (NOAA). (2020). What is Coral Bleaching? Retrieved from https://oceanservice.noaa.gov/facts/coral_bleach.html
