How does climate change affect the pH of the Southern Ocean?

Arabia Weather - The effects of global warming extend to the Southern Ocean, where extreme weather phenomena and unprecedented climate disasters are witnessed.

In the southern hemisphere, Antarctica is located, a place where peace and tranquility are characterized, mixed between the whisper of the wind and the sounds of some animals searching for their food. This continent is surrounded by the Southern Ocean, which is considered the fourth largest ocean in the world. However, a recent study has revealed the circulation of climate change in this region, where ocean acidity is expected to rise by 2100, portending a negative impact on marine life and threatening areas with rich biodiversity.

The results of this study were published in the journal Nature Communications on January 4, 2024.

Ocean acidity

“Ocean acidification” is a term that refers to a reduction in the pH level of seawater, meaning an increase in pH. According to the study, researchers expect the pH level to drop by as much as 0.36, indicating an increase in water acidity of more than 100% compared to water pH levels in the 1990s. The upper part of the ocean waters, up to 200 meters high, is seeing an increase in this acidity, and the increase is expected to be greater at the depth of the ocean.

This increase in water acidity is a threat to biodiversity in these areas, as many marine organisms, such as penguins and whales, depend on certain acidity conditions to survive. In addition, this negative impact of ocean acidity extends deeper into the water, making it a greater threat to marine biodiversity at all depths.

Global warming phenomenon

The phenomenon of global warming worsened significantly after the beginning of the industrial revolution, which negatively affected ecosystems and had clear impacts on the life of creatures on Earth. In 2015, the twenty-first session of the Conference of the Parties (COP21) was held in Paris, where parties committed to working to maintain global average temperatures, not exceeding 1.5 degrees Celsius by 2030. However, things appear to have gone beyond expectations, The year 2023 recorded the highest temperatures ever recorded, reaching 1.48 degrees Celsius above pre-industrial revolution levels.

On the other hand, the oceans play an essential role in moderating the planet's temperature, absorbing about 30% of the carbon dioxide produced by human activity around the world. However, as the amount of carbon dioxide dissolved in ocean water increases, the pH level decreases and the acidity of ocean water increases.

Simulating climate scenarios

There are some protected areas in the waters of the Southern Ocean, where human activities, such as fishing, are prohibited. Scientists suggest protecting more marine areas, covering about 60% of this area, especially since it includes a wide range of marine species. Among those areas proposed for protection, the Weddell Sea stands out as a haven for many marine organisms.

However, when researchers ran a computer model to simulate changes in Southern Ocean waters over the course of the 21st century, they found that even marine protected areas, including the Weddell Sea, would face a significant rise in pH by the end of this century. They created some scenarios:

In a worst-case scenario, where researchers expect anthropogenic emissions to increase without mitigation and emissions reduction measures, the Ross Sea is expected to see an average rise in water acidity of 104% by 2100, which would pose a major challenge for this region, which is the largest marine reserve. In the world, it is located off the northern tip of Antarctica.

In the case of the second scenario, which depends on a moderate reduction in carbon emissions, the acidity of the Ross Sea water is expected to rise by 43%. Although this scenario is considered less dire than the first, it has potentially unsustainable impacts on marine organisms, including phytoplankton that form an important part of the food web.

The study's authors stress the need to strengthen efforts to reduce emissions and adapt the marine environment to these severe transformations, noting the importance of immediate action to save the current situation, especially in light of the rapid increase in global average temperatures.

Source: al-ain