by faster | Feb 17, 2019 | Blog
SOURCE: The Guardian DATE: February 17, 2019 SNIP: Dramatic rises in atmospheric methane are threatening to derail plans to hold global temperature rises to 2C, scientists have warned. In a paper published this month by the American Geophysical Union, researchers say sharp rises in levels of methane – which is a powerful greenhouse gas – have strengthened over the past four years. Urgent action is now required to halt further increases in methane in the atmosphere, to avoid triggering enhanced global warming and temperature rises well beyond 2C. “What we are now witnessing is extremely worrying,” said one of the paper’s lead authors, Professor Euan Nisbet of Royal Holloway, University of London. “It is particularly alarming because we are still not sure why atmospheric methane levels are rising across the planet.” [Ed note: Perhaps these guys need to get together with these guys.] During much of the 20th century, levels of methane, mostly from fossil fuel sources, increased in the atmosphere but, by the beginning of the 21st century, it had stabilised, said Nisbet. “Then, to our surprise, levels starting rising in 2007. That increase began to accelerate after 2014 and fast growth has continued.” Studies suggest these increases are more likely to be mainly biological in origin. However, the exact cause remains unclear. Some researchers believe the spread of intense farming in Africa may be involved, in particular in tropical regions where conditions are becoming warmer and wetter because of climate change. However, other scientists warn that there could be a more sinister factor at work. Natural chemicals in the atmosphere – which help to break down methane...
by faster | Feb 12, 2019 | Blog
SOURCE: Yale Climate Connections DATE: February 12, 2019 SNIP: About a fifth of the Northern Hemisphere landmass is permafrost, ground that has been mostly frozen for half a million years or more. Now there are signs of thaw appearing in many places across this vast landscape circling the Arctic, and at accelerated rates. It is only a matter of time until the incremental thawing of the permafrost reaches a tipping point of no return, a state of accelerated and irreversible change, the side effects of which might well push other parts of the Arctic beyond their own tipping points. Quite possibly, we are poised to witness such a transformation within our lifetimes – ice sheet loss, increased frequencies of fires in the tundra and boreal forests, and complete habitat loss for marine mammals, to name just a few examples of the changes that could occur. The major side effect of a thawing permafrost is that it will further enhance global warming with the release of large quantities of methane, a potent greenhouse gas. The permafrost contains organic matter, and thawing will enable bacterial decomposition that will release methane as a byproduct of anaerobic respiration. The last time there was a large-scale thaw of the permafrost was four interglacials ago. Evidence of this thawing event can be found in Siberian caves where stalactites and stalagmites growth last occurred at that time. Such deposits can only form when there is liquid water flowing. At the time of the thaw, about 450,000 years ago, the climate was about 1.5°C warmer than pre-industrial temperatures. Today, the temperature is nearly as warm – 1°C...
by faster | Jan 3, 2019 | Blog
SOURCE: Phys.org DATE: January 3, 2019 SNIP: The Greenland Ice Sheet emits tons of methane according to a new study, showing that subglacial biological activity impacts the atmosphere far more than previously thought. An international team of researchers led by the University of Bristol camped for three months next to the Greenland Ice Sheet, sampling the meltwater that runs off a large catchment (> 600 km2) of the Ice Sheet during the summer months. As reported in Nature, using novel sensors to measure methane in meltwater runoff in real time, they observed that methane was continuously exported from beneath the ice. They calculated that at least six tons of methane was transported to their measuring site from this portion of the Ice Sheet alone. Professor Jemma Wadham, Director of Bristol’s Cabot Institute for the Environment, who led the investigation, said: “A key finding is that much of the methane produced beneath the ice likely escapes the Greenland Ice Sheet in large, fast flowing rivers before it can be oxidized to CO2, a typical fate for methane gas which normally reduces its greenhouse warming...
by faster | Nov 20, 2018 | Blog
SOURCE: Newsweek and Scientific Reports DATE: November 20, 2018 SNIP: Huge amounts of methane are being released from a glacier connected to Katla—one of Iceland’s largest and most active volcanoes. Researchers found that up to 41 tonnes of methane is released through meltwater from the Sólheimajökull glacier every day over the summer months. The study, published in Scientific Reports, is the first to show methane is released from glaciers on such a large scale. Methane is a greenhouse gas far more potent than carbon dioxide. It is becoming of increasing concern because of its potential to contribute to climate change. In Arctic regions, methane is locked up in permafrost—ground that is permanently frozen. As global temperatures increase, the soil thaws and methane is released, contributing to further warming. Identifying and understanding previously unrecognized sources of methane—like the latest study on glaciers—is hugely important to climate change models. If this volcano and glacier is representative of other similar systems, it could mean masses of previously unaccounted methane are being released into the atmosphere. The team took water samples from the edge of the lake in front of the glacier to measure the concentrations of methane. They found that compared to other nearby rivers and sediments, the levels were far higher. The highest concentrations of methane were at the point where the river emerges from beneath the glacier. Further analysis allowed them to find the exact sources of the methane—microbiological activity on the glacier bed. When methane comes into contact with oxygen it normally combines to form carbon dioxide. However, at Sólheimajökull when the meltwater reaches the bed of the glacier...
by faster | Nov 13, 2018 | Blog
SOURCE: EOS and Journal of Geophysical Research DATE: November 13, 2018 SNIP: As cities around the world continue to swell, urban dwellers account for a larger and larger share of the world’s greenhouse gas emissions. In fact, the 2014 Intergovernmental Panel on Climate Change report attributes more than 70% of anthropogenic emissions to cities. To mitigate climate change, scientists and policy makers believe it is crucial to establish reliable estimates of urban emissions and their sources. Recent research suggests that state and national greenhouse gas inventories poorly characterize urban emissions—particularly for methane, which carries more global warming potency than carbon dioxide on a per mass basis over a 20-year horizon. Now Ren et al. suggest these inventory estimates may actually be lower than observed values, by a factor of nearly 3 in some metropolitan areas. The results indicate that landfills play a more significant role in methane emissions than previously believed: The total methane emitted from the monitored dumps exceeded prior estimates by a factor of roughly 2. One site alone, the Brown Station landfill, spewed greater than 9 times more methane than the values reported by the Environmental Protection Agency’s Greenhouse Gas Reporting Program, even though the landfill gas collection and control system was in operation on the site. The study also found that the region’s natural gas system—another major source of pollution—accounts for 40%–60% of the region’s methane emissions. The researchers have been working closely with the Maryland Department of the Environment to get the best possible inventories so that the state can reach its rigorous greenhouse gas reduction...
