Blogs / 80beats

Alarming but preliminary reports of methane gas bubbling up from the Arctic Ocean have raised the specter of precipitous global warming in the minds of some climate scientists.

While aboard a research ship sailing off the coast of Siberia, scientists observed high levels of methane in the water, and then spotted several areas where the gas bubbles were fizzing up from the ocean floor, which contains vast amounts of frozen methane. That was enough to ring the alarm bells: Methane is about 20 times more powerful as a greenhouse gas than carbon dioxide and many scientists fear that its release could accelerate global warming in a giant positive feedback where more atmospheric methane causes higher temperatures, leading to further permafrost melting and the release of yet more methane [The Independent].

While the news seems disquieting, some researchers are expressing some skepticism about the findings, which haven’t yet been published in a peer-reviewed journal. The initial word from a heap of scientists who are focused on sub-sea methane deposits, including a group that videotaped big burps of methane bubbles off Santa Barbara, Calif., a few years ago, is a note of caution about overinterpreting the Arctic bubbling and high gas concentrations as something a) new or b) driven by human-caused global warming [The New York Times, Dot Earth blog].

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Methane, a natural gaseous byproduct of both rotting garbage in landfills and raw sewage, is increasingly regarded as being valuable. Instead of allowing methane to float up into the atmosphere, waste companies are increasingly harnessing it for use as heating gas and as a means to produce electricity [San Francisco Chronicle blog]. It seems to be an alternative energy whose time has come: Methane landfill projects are already online in almost every state, and San Antonio has just signed on to become the first city to harvest methane from its sewage treatment facility.

Harvesting methane serves a two-fold purpose: If it is not captured, the E.P.A. says, landfill methane becomes a greenhouse gas at least 20 times more potent than carbon dioxide, the principal greenhouse gas, when it rises into the atmosphere. The agency estimates that landfills account for 25 percent of all methane releases linked to human activity. As a result, capturing methane at former and active landfills is a global housekeeping benefit as well as an important alternative energy niche [The New York Times].

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The Earth was an inhospitable place 635 million years ago, when ice sheets that extended to the equator. Scientists have long wondered how the planet rebounded from that icy era, known as “Snowball Earth.”

Now a new study suggests that a stream of methane gas escaping from the ice brought the planet to a climate tipping point and transformed it into a lush, tropical world, in what researchers called one of the most severe climate change events recorded in Earth history [Nature, subscription required].

Paleoclimatology has become a hot field, as researchers believe that the planet’s dramatic prehistoric climate shifts can help predict the effects of present-day global warming. Since methane figures into one of the most ominous global warming scenarios, this latest study is being eagerly scrutinized for clues to our planet’s fate.

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