An investigation led by Lancaster University has revealed that glaciers are a potential source of large methane emissions. The Sólheimajökull glacier, which flows from the active volcano Katla in Iceland, was found to release up to 41 tons of methane through meltwaters every day during the summer months.
Study co-author Dr. Peter Wynn is a glacial biogeochemist from the Lancaster Environment Centre.
“This is a huge amount of methane lost from the glacial meltwater stream into the atmosphere,” said Dr. Wynn. “It greatly exceeds average methane loss from non-glacial rivers to the atmosphere reported in the scientific literature. It rivals some of the world’s most methane-producing wetlands; and represents more than twenty times the known methane emissions of all Europe’s other volcanoes put together.”
“Methane has a global warming potential 28 times that of carbon dioxide (CO2). It is therefore important that we know about different sources of methane being released to the atmosphere and how they might change in the future.”
“There has been a lot of speculation about whether or not glaciers can release methane. The beds of glaciers contain the perfect cocktail of conditions for methane production – microbes, low oxygen, organic matter and water – along with an impermeable cap of ice on the surface trapping the methane beneath.”
“However, nobody has thoroughly investigated this in the field before and this is the strongest evidence yet that glaciers are releasing methane.”
Dr. Rebecca Burns, who participated in the study as a graduate researcher, collected water samples from the edge of the melt water lake in front of the Sólheimajökull glacier. She measured the methane concentrations and compared them with methane levels in nearby rivers and sediment.
“The highest concentrations were found at the point where the river emerges from underneath the glacier and enters the lake. This demonstrates the methane must be sourced from beneath the glacier,” explained Dr. Wynn.
Using a mass spectrometer, the researchers determined that the methane is originating from microbiological activity in the bed of the glacier. The team attributes this activity to the Katla volcano.
“We believe that while the volcano is not producing the methane, it is providing the conditions that allow the microbes to thrive and release methane into the surrounding meltwaters,” said Dr. Wynn.
Study co-author and volcanologist Dr. Hugh Tuffen added, “The heat from Katla volcano may greatly accelerate the generation of microbial methane, so in fact you could see Katla as a giant microbial incubator.”
“Scientists have also recently discovered that Katla emits vast amounts of CO2 – it’s in the top five globally in terms of CO2 emissions from volcanoes – so Katla is certainly a very interesting, very gassy volcano.”
Dr. Burns pointed out that there are many other ice-covered, active volcanoes and geothermal systems in Iceland and Antarctica.
“The recent International Panel on Climate Change (IPCC) report highlights that current trajectories indicate global warming is likely to reach 1.5oC between 2030 and 2052, with greatest perceived climate sensitivity at higher latitudes,” said Dr. Burns. “If methane produced under these ice caps has a means of escaping as the ice thins, there is the chance we may see short term increases in the release of methane from ice masses into the future.”
The study is published in the journal Scientific Reports.