New Source of Global Warming Discovered in the Canadian Arctic

It turns out that permafrost may be contributing more to greenhouse gases than we thought. Scientists have discovered that methane emissions produced by thawing permafrost in the Canadian Arctic are greatly underestimated in current climate models. The findings reveal the importance of taking every factor into account when it comes to creating future models.

The culprits in this case are small thaw ponds. These ponds are a significant source of methane emissions. During the course of the study, the scientists compared ponds of different shapes and sizes and studied their physiochemical properties and microbial technology. Using radiocarbon dating as well as next-generation molecular tools, they studied the sediment and examined the carbon transformation process.

"We discovered that although the small shallow ponds we studied represent only 44 percent of the water-covered surface in a Bylot Island valley, they generate 83 percent of its methane emissions," said Karita Negandhi, one of the researchers, in a news release.

What is more interesting is where the methane from these ponds comes from. The isotopic signatures of the methane emitted from the ponds indicate that the gas comes from old carbon reserves that have been sequestered in the permafrost for millennia. As the permafrost thaws, organic matter becomes more abundant and promotes the proliferation of aquatic microbes such as methanogenic Archaea, which use various sources of carbon, then release it into the atmosphere in the form of methane and CO2. Consequently, longer summers could lead to an increase in these emissions.

So how did this source of emissions remain unnoticed for so long? The small thaw ponds are located in remote regions. This means that there are logistical restraints when it comes to studying them. Yet in the context of global warming, studying them may very well be worth it. They could have an increasingly significant incidence of transfer of greenhouse gases into the atmosphere in the future.

The findings are published in the journal PLOS One.