How oceans cool the climate: sulfur emissions and global warming

Oceans emit far more sulfur compounds than previously thought. These emissions play a crucial role in cooling the climate, changing our understanding of the processes regulating Earth’s temperature. The latest findings, based on advanced mathematical models and detailed field measurements, reveal for the first time the significant role of the ocean in the climatic balance of Earth.

A new perspective on sulfur emissions

Previous research primarily focused on the role of dimethyl sulfide (DMS), a key sulfur gas emitted by oceans. DMS participates in the creation of sulfur aerosols, which increase the ability of clouds to reflect solar radiation, contributing to the cooling of the atmosphere. However, recent studies published in Science Advances point to another significant compound – methanethiol (MeSH). Arising from biological processes occurring in the oceans, methanethiol has a significant impact on the chemical composition of the atmosphere, and its role in climate regulation had long been overlooked.

Methanethiol – the hidden hero of the climate balance

Methanethiol (CH₃SH), also known as MeSH, is a highly reactive gas that is difficult to detect using traditional research methods. Thanks to advanced analytical technologies, scientists discovered that MeSH accounts for a significant portion of the sulfur emitted by oceans, especially in regions like the Southern Ocean. According to researchers, emissions of this gas could increase the amount of sulfur aerosols in the atmosphere by 30–70%, significantly strengthening the cooling effect on the climate.

Advanced technologies for studying emissions

Scientists have created a global database of methanethiol concentrations in ocean waters, including samples collected from various parts of the world, including extreme conditions in the Arctic and Southern Oceans. Through the analysis of this data, precise maps of gas emissions were created, allowing for a more accurate estimation of its impact on the atmosphere.

Research utilized mathematical modeling combined with satellite data, providing detailed information about the chemical composition of the atmosphere. Scientists demonstrated that the presence of methanethiol in the atmosphere extends the lifespan of dimethyl sulfide, allowing it to be transported over greater distances and enhancing the global cooling effect.

The Southern Ocean as a key research area

The Southern Ocean has proven to be a particularly important research area. Methanethiol emissions in this region are exceptionally intense, making the Southern Ocean one of the most crucial elements of global climate regulation. Its importance stems from its key role in global atmospheric and oceanic circulation, influencing energy transport, gas exchange, and climate stability.

Sulfur aerosols, formed from MeSH emissions, increase the albedo of clouds over the Southern Ocean, i.e., their ability to reflect solar radiation. This reduces the amount of energy reaching the Earth’s surface, leading to local and global cooling of the atmosphere. The Southern Ocean, acting as a natural climate buffer, thus slows down the pace of global warming.

Additionally, this region is one of the main sites for absorbing carbon dioxide (CO₂) from the atmosphere thanks to the biological carbon pump processes, supported by phytoplankton activity. Methanethiol emissions may affect phytoplankton ecosystems, changing the dynamics of CO₂ absorption and potentially modifying processes related to the carbon cycle.

The Southern Ocean also plays a crucial role in global oceanic circulation, including the thermohaline circulation process. Changes in the salinity and temperature of waters in this area can significantly affect the intensity and direction of global ocean currents. These, in turn, impact the climate in other parts of the world, shaping phenomena such as the intensity of monsoons in Asia or weather patterns in Europe and North America.

Significance of research for climate policy

These discoveries have far-reaching consequences for both science and climate policy. A better understanding of the role of oceans in regulating global temperature enables the development of more effective strategies to combat climate change. The research results may also influence international negotiations on greenhouse gas emissions, emphasizing the importance of protecting marine ecosystems as a key element of climate strategies.

The research also provides precise data that can be incorporated into climate models used to predict temperature increases. This is an immensely important contribution to shaping climate policy and developing effective adaptation plans.