A new study shows that frozen methane emissions are more likely to melt due to climate change and could be released into the ocean.
An international research team led by the University of Newcastle has discovered that when frozen methane is discharged and ice melts, methane is released and travels from the deepest parts of continental slopes to the edges of underwater shelves.
They also found a pocket that had traveled 25 miles (40 km). Researchers said this means even more methane could potentially become vulnerable and released into the atmosphere as the climate warms.
research,’Long-distance transport and emission of methane from the bottom of the hydrate stability zone” is published. natural earth science.
How methane emissions contribute to climate warming
Methane hydrate, or fire ice, is an ice-like structure containing methane buried under the ocean.
Large amounts of methane emissions are stored in the ocean as marine methane. As the ocean warms, it melts, releasing methane, known as dissociated methane, into the ocean and atmosphere, contributing to global warming.
The researchers used advanced three-dimensional seismic imaging techniques to examine sections of hydrate that have dissociated during climate warming off the coast of Mauritania in northwest Africa.
Researchers identified cases in which dissociated methane emissions traveled more than 40 km during past warm periods and were released through underwater depressions known as pockmarks.
Professor Richard Davies, lead author of the study, said: “When I reviewed images of the geological formations beneath the modern ocean floor off the coast of Mauritania, I found 23 pockmarks.
“Our study shows that they formed because methane released from hydrates from the deepest parts of the continental slope was released into the ocean.
“Scientists had previously thought that these hydrates would be less susceptible to climate warming, but now it turns out that some of them are.”
methane is approaching land
Researchers have previously studied how changes in seafloor temperatures near continental margins affect methane release from hydrates.
However, these studies mainly focused on regions where only a small fraction of the earth’s methane hydrate exists.
This is one of the few studies to investigate methane emissions from the bottom of hydrate stability zones deep underwater. The results show that the methane released from the hydrate stability zone migrated significantly toward land.
“This is an important finding. Until now, research efforts have focused on the shallowest part of the hydrate stability zone, because we thought this was the only part that would be susceptible to climate change.” says Professor Christian Berndt, head of the Ocean Geodynamics Research Unit at GEOMAR in Kiel, Germany.
“New data clearly shows that far greater amounts of methane can be released from ocean hydrates. To better understand the role of hydrates in the climate system, we need to investigate this issue thoroughly. It needs to be clarified.”
The findings could play an important role in predicting and addressing the impact of methane on a changing climate.
Future uses of the research
The researchers plan to continue looking for evidence of methane vents along the margin and predict where large methane seeps may occur as the planet warms.
Researchers are now planning a scientific expedition to examine the pockmarks more closely and see if they can be more closely linked to past climate warming events.