Previous studies of ice cores from Greenland and Antarctica have shown that when global climates warmed between 14,000 and 11,500 years ago, levels of methane in the atmosphere increased significantly. There was also an unidentified northern source of the gas at that time.
According to new research published in the latest edition of the journal Science (26 October), methane bubbling from Arctic lakes could have been responsible for up to 87 per cent of this northern source. The findings could help climate modellers to assess how warming affects atmospheric levels of methane, a potent greenhouse gas.
Previous hypotheses suggested that the increase came from gas hydrates or wetlands. The new study's findings indicate that methane bubbling from thermokarst lakes, which are formed when permafrost thaws rapidly, is likely to be a third and major source.
'Our research focused on areas of Siberia and Alaska which, during the last ice age, were dry landscapes underlain by deep permafrost,' commented co-author Professor Mary Edwards of the University of Southampton's School of Geography. 'As the climate warmed, the permafrost thawed, forming thermokarst lakes. When the permafrost around and under the lakes thawed, it would have released organic material into the lakes - primarily dead plant material - which would be a good energy source for methane-producing bacteria. Under such conditions, carbon which had been locked in the ground for thousands of years could rapidly be converted into potent greenhouse gases: methane and carbon dioxide.'
The group's calculations suggest that the lakes contributed 33 to 87 per cent of the methane increase from northern sources. The team examined lakes in Siberia and northern Alaska that currently release methane. They gathered samples of permafrost and thawed them in the laboratory to measure the levels of methane that permafrost soil can produce immediately after thawing. Using geological data they were able to reconstruct the pattern of lake formation since the end of the last ice age.
'Thermokarst lake formation is a source of atmospheric methane today, but it was even more important during the warming that took place at the end of the ice age,' continues Professor Edwards. 'It is possible that, with global warming, large releases from these lakes may occur again in the future.'
Sarah Watts | alfa
UCI and NASA document accelerated glacier melting in West Antarctica
26.10.2016 | University of California - Irvine
Ice shelf vibrations cause unusual waves in Antarctic atmosphere
25.10.2016 | American Geophysical Union
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences