New research reveals that fire ice or frozen methane trapped under the ocean is in danger of melting due to climate change, potentially releasing large amounts of methane into the atmosphere. Using advanced seismic imaging techniques, the team found that dissociated methane can travel great distances, challenging previous assumptions about methane's stability.

Research shows that ocean fire ice or frozen methane can easily melt due to climate change, posing a significant threat to release methane into the atmosphere. An international team of researchers led by Newcastle University has found that as frozen methane and ice melt, methane - a potent greenhouse gas - is released and moves from the deepest parts of the continental slope to the edge of the underwater continental shelf. They even found a pocket of methane that traveled 25 miles (40 kilometers).

Writing in the journal Nature Geoscience, the researchers said this means more methane may be vulnerable to being released into the atmosphere due to climate warming.

Methane Hydrates: A Hidden Climate Threat

Methane hydrate, also known as fire ice, is an ice-like structure buried under the sea that contains methane. Large amounts of methane are stored on the seafloor as marine methane. When the ocean warms, it thaws, releasing methane, known as dissociated methane, into the ocean and atmosphere, causing global warming.

Scientists used advanced three-dimensional seismic imaging technology to study the fraction of hydrates that dissociate as the climate warms off the coast of Mauritania in northwest Africa. They found one specific case where dissociated methane migrated more than 40 kilometers during past warming periods and was released through an underwater depression known as a "pocket."

Researchers at Newcastle University have found that frozen methane trapped under the ocean is easily melted by climate change and could be released into the sea. Source: Newcastle University

Discovery and Impact

Lead author Professor Richard Davies, Vice-Chancellor for Global and Sustainability at Newcastle University, said: "During the COVID-19 epidemic, I re-examined the imaging of modern seafloor strata offshore Mauritania and almost accidentally discovered 2 3 pockmarks. Our work shows that they form as methane is released into the ocean from hydrates in the deepest parts of the continental slope. Scientists previously thought these hydrates were not affected by climate warming, but our study shows that some of them are."

Researchers have previously studied how changes in underlying water temperatures near continental margins affect the release of methane from hydrates. However, these studies have focused on regions where only a small portion of the world's methane hydrates are located. This study is one of the few to examine methane release at the bottom of the hydrate stability zone (further underwater). The results show that methane released from the hydrate stabilization zone travels great distances landward.

Broader research prospects and future plans

Professor Dr. Christian Berndt, Director of the GEOMAR Marine Geodynamics Research Unit in Kiel, Germany, added:

"This is an important finding. Until now, research efforts have focused on the shallowest parts of the hydrate stability zone because we thought this was the only part that would be sensitive to changes in climate. The new data clearly show that the amount of methane being released from ocean hydrates could be much greater, and we really have to figure this out to better understand the role of hydrates in the climate system."

Methane is the second largest anthropogenic greenhouse gas after carbon dioxide. According to the U.S. Environmental Protection Agency, methane accounts for about 16% of global greenhouse gas emissions.

The findings could play a key role in helping predict and address methane's impact on our changing climate.

The team plans to continue looking for evidence of methane vents along the edge and try to predict where large methane seeps might occur as the planet warms. The researchers are now planning a scientific cruise to drill through the pockmarks to see if they can more closely link them to past warming events.

Reference: "Long-distance migration and emission of methane at the bottom of the hydrate stability zone" published by Richard J. Davies, Jinxiu Yang, Mark T. Ireland, Christian Berndt, Miguel Ángel Morales Maqueda and Mads Huuse on December 6, 2023, "Nature - Earth Sciences".

DOI:10.1038/s41561-023-01333-w

Compiled source: ScitechDaily