Warming ocean contributes to global warmingAugust 17, 2009Global warming The warming of an Arctic current over the last 30 years has triggered the release of methane, a potent greenhouse gas, from methane hydrate stored in the sediment beneath the seabed. Scientists at the National Oceanography Centre Southampton working in collaboration with researchers from the University of Birmingham, Royal Holloway London and IFM-Geomar in Germany have found that more than 250 plumes of bubbles of methane gas are rising from the seabed of the West Spitsbergen continental margin in the Arctic, in a depth range of 150 to 400 metres. Methane released from gas hydrate in submarine sediments has been identified in the past as an agent of climate change. The likelihood of methane being released in this way has been widely predicted. The data were collected from the royal research ship RRS James Clark Ross, as part of the Natural Environment Research Council's International Polar Year Initiative. The bubble plumes were detected using sonar and then sampled with a water-bottle sampling system over a range of depths. The results indicate that the warming of the northward-flowing West Spitsbergen current by 1° over the last thirty years has caused the release of methane by breaking down methane hydrate in the sediment beneath the seabed. Professor Tim Minshull, Head of the University of Southampton's School of Ocean and Earth Science based at that the National Oceanography Centre, says: "Our survey was designed to work out how much methane might be released by future ocean warming; we did not expect to discover such strong evidence that this process has already started." Methane hydrate is an ice-like substance composed of water and methane which is stable in conditions of high pressure and low temperature. At present, methane hydrate is stable at water depths greater than 400 metres in the ocean off Spitsbergen. However, thirty years ago it was stable at water depths as shallow as 360 metres. This is the first time that such behaviour in response to climate change has been observed in the modern period. While most of the methane currently released from the seabed is dissolved in the seawater before it reaches the atmosphere, methane seeps are episodic and unpredictable and periods of more vigorous outflow of methane into the atmosphere are possible. Furthermore, methane dissolved in the seawater contributes to ocean acididfication. Graham Westbrook Professor of Geophysics at the University of Birmingham, warns: "If this process becomes widespread along Arctic continental margins, tens of megatonnes of methane per year - equivalent to 5-10% of the total amount released globally by natural sources, could be released into the ocean." The team is carrying out further investigations of the plumes; in particular they are keen to observe the behaviour of these gas seeps over time. National Oceanography Centre, Southampton (UK) |
|||||||||||||||||||||
| Related Global Warming Current Events and Global Warming News Articles Oceans' uptake of manmade carbon may be slowing The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. Research challenges for understanding landscape changes identified Nine research challenges and four research initiatives that are poised to advance the study of how Earth's landscapes change were unveiled today in a new report by the National Research Council. Study: Sea stars bulk up to beat the heat A new study finds that a species of sea star stays cool using a strategy never before seen in the animal kingdom. The sea stars soak up cold sea water into their bodies during high tide as buffer against potentially damaging temperatures brought about by direct sunlight at low tide. Drug industry, nonprofits join forces to fight world's neglected diseases Drug companies and nonprofit organizations are joining forces to develop new drugs and vaccines to target so-called "neglected" diseases that claim millions of lives in the developing world each year. Health care accounts for 8 percent of US carbon footprint The American health care sector accounts for nearly a tenth of the country's carbon dioxide emissions, according to a first-of-its-kind calculation of health care's carbon footprint. Cave Study Links Climate Change to California Droughts California experienced centuries-long droughts in the past 20,000 years that coincided with the thawing of ice caps in the Arctic. Reducing greenhouse gases may not be enough to slow climate change Because land use changes are responsible for 50 percent of warming in the US, policymakers need to address the influence of global deforestation and urbanization on climate change, in addition to greenhouse gas emissions. Past climate of the northern Antarctic Peninsular informs global warming debate The seriousness of current global warming is underlined by a reconstruction of climate at Maxwell Bay in the South Shetland Islands of the Antarctic Peninsula over approximately the last 14,000 years, which appears to show that the current warming and widespread loss of glacial ice are unprecedented. Climate variability impacts the deep sea Deep-sea ecosystems occupying 60% of the Earth's surface could be vulnerable to the effects of global warming warn scientists writing in the Proceedings of the National Academy of Sciences. Interactions with aerosols boost warming potential of some gases For decades, climate scientists have worked to identify and measure key substances -- notably greenhouse gases and aerosol particles -- that affect Earth's climate. More Global Warming Current Events and Global Warming News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||