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Global Warming Blog

The Methane Menace
New findings show methane feedback loops may be well underway
Posted September 9, 2006 by Nathan Cool

Carbon dioxide gets all the attention these days as the iniquitous bearer of worldly warmth. Although widely abundant, CO2 is not necessarily the most menacing of heat-trapping gases posing threats of torridity to our planet. Methane, a gas released from various natural and human sources, is second in the lineup of greenhouse gas troublemakers, being 20 times more capable of holding in heat than carbon dioxide. While methane deserves attention, it recently--and rightfully--stole the spotlight as new studies discuss how nature, being influenced by a cyclic effect of climate change, may be releasing copious quantities of methane into the atmosphere--possibly far more than was anticipated by earlier studies. What's worse though is that a naturally occurring spiral of intensification known as a "feedback loop" is expected to make this problem even worse.

One of the uncertainties in climate science is how feedback loops may intensify the global warming effect in a world where temperatures are beginning to rise. In chapter 5 of Is it Hot in Here?--The simple truth about global warming, I discussed how a feedback loop is similar to holding a microphone in front of an amplifier: a cyclic loop of cause and effect feeds on itself, escalating a process already underway. In the case of the microphone and amplifier, the sound of the amplifier's speaker is sent into the microphone, which is sent to the amplifier, which adds more noise into the microphone, which is sent into the amplifier...again, and again, until an annoying, ear-piercing squeal rings ever so loudly. This kind of feedback also happens in nature.

In the case of global warming, the feedback involves greenhouse gases and heat--instead of a microphone and amplifier. For instance, abundant quantities of methane await their release in old, rotted foliage lying in the cold grips of permafrost covering the icy ground of Arctic tundra. If the tundra thaws out, then this methane can be released. If methane is released, then global temperatures could rise further from these unconfined greenhouse gases, which could cause further permafrost melting, which could lead to more methane being released, which could lead to further warming, and so on, and so on, etc., until the shrill of the global warming alarm bell screams loud and clear. Or so the theory goes. It is a plausible theory, well accepted in fact, but the gray area lies within the understanding of just how these feedback loops will react, and how far they may--or may not--spiral out of control.

Three recent reports show that some feedback loops may be primed for what could result in precarious consequences. One study, conducted by researchers from the University of California, Davis, was published in the Proceedings of the National Academy of Sciences (Click here for their report.) The UC Davis team found that after digging into seafloor sediments off the California coast and analyzing methane content trapped within ancient layers of tar, a 32,000-year-old diary of the past revealed some seemingly disturbing trends. The UC Davis team found that when global temperatures rose, massive quantities of methane were released from the oceans--something the UC Davis team theorizes occurred at the end of our last ice age. Using this data, the UC Davis team posits that as the world warms, oceans release more methane. As more methane is then released, the feedback loop can intensify, and warming could be exacerbated.

But, another study in the journal Science, conducted by researchers from the University of Victoria, (discussed here) shows that the warm-up our world experienced at the end of the last ice age had nothing to do with methane being released from oceans; instead, it points to permafrost. This aligns with findings being published in the journal Nature by an international team of U.S. and Russian scientists who found that thawing permafrost is enlarging northern lakes, which is assisting the thawing effect, which is releasing methane that was once frozen safely away in the Arctic ground.

In all of these studies, researchers do agree on one thing: the methane currently being released from lakes, oceans and permafrost, as well as the feedback loops underway, seem to be greater than expected. These studies though are still underway, and much is still unknown about the diaries of the past being analyzed in seafloor sediments, frozen layers of permafrost, ice core samples, modern measurements of methane, and how much natural variability is to blame. Many questions remain.

For instance, when it comes to feedback loops like this whole methane mess, it's assumed that worldwide warming will continue. But other elements of nature are affected when the world starts to heat up. Clouds, for instance, may become more abundant as the atmosphere becomes more laden with moisture. This moisture has to come down somewhere, and in places experiencing temperatures below 32°F in the winter, this means snow--possibly more than received now. Winters could be shorter, but snowfall could become more abundant, thus keeping extra layers of ice over now-melting permafrost.

The proliferation of clouds in a warming world could also dim energy from the Sun and cool things down as well. So, could the feedback loops underway now find an eventual point of equilibrium, equal out, and then retreat? Possibly.

Last week, climate scientists with the IPCC reportedly downgraded the severity of the effects of a warming world--something I discussed here. Yet this week, a trilogy of reports now sways to the gloom and doom idea. So what gives?

One of the things I stress in Is it Hot in Here? is that scientific study takes rigor, data, trial and error. A new study does not alone provide ample evidence that something is indeed fact (that's why these things are called theories). After all, just 30 years ago there were fears of an upcoming ice age. Today though, only a few decades later, mentioning that idea labels one as nonsensical--a reminder of the nascent nature of global warming research, and how much is still unknown.

Continued research, such as that being conducted by the various teams looking into these methane feedback loops is critical. Science deserves the fair shake--not sky-is-falling alarmism or forget-about-it hand waving. Knowing the facts, and keeping an eye on the truth within the developments of this burgeoning science will help to guide us all toward a safer, environmentally sound and balanced future. Future methane concentration measurements could serve as bellwethers of feedback loops, but should we wait that long to see a possible crisis unfold? Or should we invest and finance technologies now to avoid what could be a significantly balmy future? There's a price to pay either way--the monetary alternative though may be more logical, and a surefire, safe bet.

More information on feedback loops, future projections, effects from methane and their sources, greenhouse gas concentrations, bellwethers and other topics discussed in this blog can be found in my new book, Is it Hot in Here?--The simple truth about global warming. Click here to get your copy.