Earth’s Energy Imbalance Is Heating Up Our Oceans
UNESCO reports that the Earth is warming because more energy from the sun is staying trapped in our atmosphere due to greenhouse gases. These gases, like carbon dioxide, come from human activities such as burning coal, gas, and oil. But what many people don’t know is that the oceans are taking in most of this extra heat.
Since 1960, the top 2,000 meters of the oceans have been absorbing this heat at an average rate of 0.32 watts per square meter. In just the past 20 years, this number has gone up to 0.66 watts per square meter. That may seem small, but when spread across all the world’s oceans, it adds up to a massive amount of energy.
Even over hundreds or thousands of years, the alterations brought about by this warming may not be reversible deep inside the ocean. Because of this, scientists are urging the world to collect more frequent and detailed data about ocean temperatures. Knowing how much heat is being stored in the ocean can help track how climate change is unfolding across the planet.
UNESCO: Human Activities Are Making the Ocean Sick
The ocean is changing in various ways as a result of human activity, particularly the emission of greenhouse gases. The most serious change is the warming of ocean waters, which is already harming the marine environment.
The oceans absorb about 90% of the Earth’s energy imbalance. The ocean’s heat content rises significantly as a result, particularly in the higher layers. Warmer waters reduce ocean mixing. That means less cold water rises from below and fewer nutrients get moved around. It also reduces oxygen in deeper waters, causing something called deoxygenation.
Deoxygenation is bad for fish and other marine life. If the ocean doesn’t have enough oxygen, sea creatures can’t survive. This threatens the entire ocean food chain, which includes the seafood that many people around the world rely on. It also affects the “blue economy”—industries like fishing, tourism, and shipping that depend on a healthy ocean.
Acid Oceans and Rising Seas Are Alarming Signs
Another serious problem is ocean acidification. As the ocean takes in more carbon dioxide from the air, its water becomes more acidic. This change in the ocean’s chemistry can make it hard for animals like corals, oysters, and crabs to grow their shells.
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Since the late 1980s, the average ocean surface pH has decreased by 0.017 to 0.027 units every ten years. Even though it may not seem like much, scientists are concerned about it. By 2024, 638 monitoring stations were reporting ocean pH levels, but the data is still not enough. Many parts of the world, especially near coastlines, do not have enough information to understand how acidification is spreading or worsening.
At the same time, sea levels are rising. The average worldwide sea level rose by 3.4 millimeters annually between 1993 and 2023. Rising seas are one of the clearest signs of climate change and can lead to flooding of coastal towns and cities. Advanced tools from space and in the ocean are needed to keep a close eye on how quickly and where this is happening.
UNESCO: New Tech Aims to Fight the Carbon Crisis—But Raises Questions
To help deal with the problem of too much carbon in the atmosphere, scientists and engineers are working on new technologies. One group of these is called marine carbon dioxide removal (mCDR). These methods try to use the ocean to soak up more carbon from the air.
Some of the ideas include changing the chemistry of seawater so it can take in more carbon or adding nutrients like iron to boost the growth of tiny plants called phytoplankton. As they develop, these plants take up carbon dioxide. Since 2020, there’s been a big rise in interest, with start-ups and governments investing in these methods.
But there are still many questions. Can these technologies really remove enough carbon? Could they cause other problems in the ocean? No one knows yet. Alongside this, there’s also growing interest in restoring coastal habitats like mangroves and seagrass meadows, which naturally store carbon. However, there’s still doubt about whether these projects can succeed in the long run.
The UNESCO State of the Ocean Report 2024 brings all these facts together. It indicates that the ocean is changing fast and in dangerous ways, mostly because of human activities. Understanding and tracking these changes better is now more important than ever.
