Validation! I’ve been saying this for years!* Underwater volcanic activity changes with the seasons and Earth’s orbit, and correlates with the Milankovitch (ice-age) cycle.
“Seafloor volcano pulses may alter climate,” says a news release from The Earth Institute at Columbia University.
A new study has found that volcanoes lurking hidden under the world’s oceans may play a far greater role in climate change than previously thought.
Underwater volcanoes, which were long assumed to ooze lava at relatively steady rates, in fact erupt in “strikingly regular cycles” that can range from just a couple of weeks to 100,000 years, the study found.
“People have ignored seafloor volcanoes on the idea that their influence is small — but that’s because they are assumed to be in a steady state, which they’re not,” said the study’s author, marine geophysicist Maya Tolstoy of Columbia University’s Lamont-Doherty Earth Observatory. A related study by a separate team this week in the journal Science bolsters Tolstoy’s case by showing similar long-term patterns of submarine volcanism in an Antarctic region Tolstoy did not study.
Mid-Atlantic Ridge – Courtesy USGS
“Volcanically active mid-ocean ridges crisscross earth’s seafloors like stitching on a baseball, stretching some 37,000 miles. They are the growing edges of giant tectonic plates; as lavas push out, they form new areas of seafloor, which comprise some 80 percent of the planet’s crust. Conventional wisdom holds that they erupt at a fairly constant rate–but Tolstoy finds that the ridges are actually now in a languid phase.
“Even at that, they produce maybe eight times more lava annually than land volcanoes,”** the article from Columbia University continues. “Due to the chemistry of their magmas, the carbon dioxide they are thought to emit is currently about the same as, or perhaps a little less than, from land volcanoes** — about 88 million metric tons a year. But were the undersea chains to stir even a little bit more, their CO2 output would shoot up, says Tolstoy. (See larger map of Mid-Atlantic Ridge)
May act in concert with Milankovitch cycles
“Some scientists think volcanoes may act in concert with Milankovitch cycles–repeating changes in the shape of earth’s solar orbit, and the tilt and direction of its axis — to produce suddenly seesawing hot and cold periods. The major one is a 100,000-year cycle in which the planet’s orbit around the sun changes from more or less an annual circle into an ellipse that annually brings it closer or farther from the sun. Recent ice ages seem to build up through most of the cycle; but then things suddenly warm back up near the orbit’s peak eccentricity. The causes are not clear.” (Notice that it has nothing to do with human activity.)
Alternating ridges and valleys formed by underwater volcanoes near the East Pacific Rise, a mid-ocean ridge in the Pacific Ocean. The ridges and valleys indicate ancient highs and lows of volcanic activity. Credit: Haymon et al., NOAA-OE, WHO
“Enter volcanoes. Researchers have suggested that as icecaps build on land, pressure on underlying volcanoes also builds, and eruptions are suppressed. But when warming somehow starts and the ice begins melting, pressure lets up, and eruptions surge. They belch CO2 that produces more warming, which melts more ice, which creates a self-feeding effect that tips the planet suddenly into a warm period.
Video - Watch a violently erupting underwater volcano with WHOI expedition leader Will Sellers.
Could increased CO2 from undersea eruptions trigger global warming?
Surprise, surprise! Yes, The Columbia University paper actually asks that question.
“A 2009 paper from Harvard University says that land volcanoes worldwide indeed surged six to eight times over background levels during the most recent deglaciation, 12,000 to 7,000 years ago. The corollary would be that undersea volcanoes do the opposite: as earth cools, sea levels may drop 100 meters, because so much water gets locked into ice. This relieves pressure on submarine volcanoes, and they erupt more. At some point, could the increased CO2 from undersea eruptions start the warming that melts the ice covering volcanoes on land? (Italics added)
“That has been a mystery, partly because undersea eruptions are almost impossible to observe. However, Tolstoy and other researchers recently have been able to closely monitor 10 submarine eruption sites using sensitive new seismic instruments. They have also produced new high-resolution maps showing outlines of past lava flows. Tolstoy analyzed some 25 years of seismic data from ridges in the Pacific, Atlantic and Arctic oceans, plus maps showing past activity in the south Pacific.
“Closely related changes in earth’s orbit”
Again, I’ve been saying this all along.
“The long-term eruption data, spread over more than 700,000 years, showed that during the coldest times, when sea levels are low, undersea volcanism surges, producing visible bands of hills. When things warm up and sea levels rise to levels similar to the present, lava erupts more slowly, creating bands of lower topography. Tolstoy attributes this not only to the varying sea level, but to closely related changes in earth’s orbit. (Italics added)
“When the orbit is more elliptical, Earth gets squeezed and unsqueezed by the sun’s gravitational pull at a rapidly varying rate as it spins daily — a process that she thinks tends to massage undersea magma upward, and help open the tectonic cracks that let it out. When the orbit is fairly (though not completely) circular, as it is now, the squeezing/unsqueezing effect is minimized, and there are fewer eruptions.
“The findings may now mean that models predicting how human activity will change the climate will need to be adjusted,” the article suggests. Volcanic eruptions are known to throw huge amounts of gas into the atmosphere, including carbon dioxide, that are (mistakenly) thought to increase global warming.
Dr Tolstoy’s data showed that almost all undersea eruptions recorded in the past 25 years occur in the first six months of the year.
This may be because the Earth is closest to the sun in January and at it’s farthest in July, creating slight squeezing and unsqueezing as it moves.
This may be similar to the effect that Dr Tolstoy detected on longer timescales as the shape of the Earth’s orbit changes.
* (See “Not by Fire but by Ice,” in particular the chapter entitled “Fish Stew”.)
** Eight times more lava annually than land volcanoes? Where in the world does that figure come from? Scientists estimate that there are more than three million underwater volcanoes, of which more than 140,000 are active. That “eight times more lava annually” figure is woefully inadequate. (See “Three million underwater volcanoes can’t be wrong“)
*** The carbon dioxide that submarine volcanoes are thought to emit “is currently about the same as, or perhaps a little less than, from land volcanoes.” Again, I question that assumption. I see no way that 140,000 underwater volcanoes could be emitting less carbon doioxide than land-based volcanoes.
See entire article from Columbia University:
http://www.earthinstitute.columbia.edu/articles/view/3231
See also, “Inconvenient study”:
http://wattsupwiththat.com/2015/02/05/inconvenient-study-seafloor-volcano-pulses-may-alter-climate-models-may-be-wrong/
http://www.sciencedaily.com/releases/2015/02/150205142921.htm
http://www.livescience.com/49710-sea-level-changes-underwater-eruptions.html
http://phys.org/news/2015-02-seafloor-volcano-pulses-climate.html
http://www.dailymail.co.uk/sciencetech/article-2942510/
Thanks to Matt Willington, J.H. Walker, Don Brown, J. Bird, John the 1st, Catherine Lawson, Ronald Baker, Vern Peterman, Petsku P, Laurel and Peter Pesola for these links
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