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How Does Climate Change Affect Our Oceans?

Around the world and throughout human history, oceans have served as a cultural bedrock for myths and traditions. Beyond providing us a sense of peace and stability, our oceans maintain us in even more concrete ways: they provide us with oxygen to breathe and food to eat.

Therefore, it is important that we understand how our oceans—an essential part of our lives—have been impacted by climate change. The ocean and atmosphere are intricately linked: oceans influence weather, and the atmosphere impacts properties of the ocean. As greenhouse gas concentrations have increased over the past 250 years, climate change has continually impacted our oceans—and below are a few of the most important of those impacts.

Increased Ocean Heat and Sea Surface Temperature

Rising greenhouse gas concentrations trap heat in Earth’s atmosphere. In fact, our oceans have done us an essential favor in that regard: the ocean has absorbed more than 90% of that extra heat since 1955, slowing atmospheric warming. However, consequently, sea surface temperature has also risen at an average rate of 0.14 degrees Fahrenheit per decade since 1901.

While heat absorption may benefit the atmosphere, rising sea temperature has its own implications. Firstly, since heat from ocean surface waters provides energy for storms, an increase in sea surface temperature alters weather patterns. Moreover, many ocean currents are driven by differences in temperature. Thus, increased heat absorption alters these currents—and the climate and ecosystems that depend on these currents. Lastly, since many plants, animals, and microbes are adapted to a certain water temperature, increasing the temperature can alter marine ecosystems, including migration and breeding patterns.

Sea Level Rise

Perhaps one of the most commonly cited impacts of climate change is sea level rise. Mean sea level has risen, on average, 0.06 inches per year over the 20th century, with the rate accelerating over recent years. However, the cause for this is not discussed as frequently. A warmer atmosphere is linked to sea level in two ways: firstly, as glaciers and ice sheets melt, this can increase the volume of water in the ocean. Secondly, as water warms, it expands slightly—and when accumulated across the entire ocean, this leads to increased ocean volume and, therefore, sea level.

Rising sea level can have a significant impact on coastal communities by inundating low-lying wetlands and dry lands. Moreover, a higher average sea level means reducing the gap between average sea level and the height of the land—thus, flooding happens more frequently.

Ocean Acidification

Finally, as the concentration of greenhouse gases such as carbon dioxide in the atmosphere increases, oceans absorb these molecules—changing the oceans’ acidity. According to the Environmental Protection Agency (EPA), oceans have absorbed about 28% of the CO2 produced by humans over the last 250 years. This CO2 reacts with seawater to produce carbonic acid. And as the concentrations of this substance increase, the ocean becomes more acidic overall.

Increased ocean acidity has significant effects on marine organisms. For example, a more acidic ocean creates more difficult conditions for corals and some types of plankton to produce calcium carbonate, a mineral that is essential for creating their shells. As these organisms struggle, this impacts the rest of the ecosystem—including humans.

Bottom Line

The impact of climate change on the ocean can seem overwhelming—but at Seaside Sustainability, we hope to conserve our oceans and educate others about the environmental concerns facing us all. There are many educational resources to help learn about this topic—in fact, the EPA website features a detailed description of each impact on our oceans. Our oceans truly provide us with everything from emotional peace to food and oxygen—so we encourage readers to learn more about the intricate connection between climate change and our oceans.


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