Heating of the seas. - North Sea hits record high temperatures: the cause explained.
Oceans, which used to be regarded as cooling agents of the Earth, are now showing signs of heating up. While the land and air are rapidly heating due to human-caused climate change, the oceans remained unaffected for quite a while - but not anymore. Scientists are alarmed as they witness ocean temperatures hitting new records. The North Sea is also showing signs of warming: The average water temperature in 2023 was almost 11.9 degrees, which is the highest recorded temperature since measurements started back in 1962 at the Biological Station Helgoland of the Alfred Wegener Institute in Bremerhaven.
This warm trend has continued into 2024, with the first four months registering some of the warmest temperatures since 1962. March 2024, in particular, saw the highest average water temperature - 6.9 degrees Celsius.
According to the Alfred Wegener Institute, each month in the German Bight has experienced temperatures relatively similar to those on the German mainland. Professor Karen Wiltshire, the director of the Biological Station Helgoland, explains why this is happening: "The North Sea is warming up fast because it's a shallow sea surrounded by land masses. It's like a large puddle that warms up quickly," she said. The temperatures rising on the mainland are in line with the rising water temperature in the North Sea. Moreover, marine heatwaves could potentially affect not only the surface waters but also the habitats on the seabed.
We're not sure why the oceans are heating up further
The reasons behind the oceans' heating up are not entirely clear. Scientists cannot provide a definite explanation for the ocean temperature increase just yet. There are several theories, but none have been confirmed. One potential reason could be the natural event of El Niño on the west coast of South America. This natural ocean current leads to warmer temperatures.
However, climate scientists believe that greenhouse gas emissions might be contributing to it as well. Since the Industrial Revolution, the oceans have absorbed about a third of global emissions, which amounts to approximately 24 million tons a day. These values are higher than they've been for over 20 million years.
The oceans have been crucial in mitigating climate change by storing vast amounts of carbon. They either transport the gas to the deep sea and deposit it there or convert it into carbon dioxide near the ocean surface through photosynthesis performed by algae and plankton. However, the impact of the increased CO2 content on ocean temperatures is still being investigated.
