Radar readings: Image shows a British Antarctic Survey aircraft conducting the survey.
Credit: Carl Robinson/British Antarctic Survey.
PARIS: A powerful volcano erupted under the icesheet of Antarctica around 2,000 years ago and it might still be active today, a finding which raises questions about ice loss from the white continent.
The explosive event – rated "severe" to "cataclysmic" on an international scale of volcanic force – punched a massive breach in the icesheet and spat out a plume some 12 kilometres into the sky, said British scientists behind the find.
Occasional volcanism
Most of Antarctica is seismically stable. But its western part lies on a rift in Earth's crust that gives rise to occasional volcanism and geothermal heat, occurring on the Antarctic coastal margins.
This is the first evidence for an eruption under the ice sheet itself – a slab of frozen water, hundreds of metres thick in places, that holds most of the world's stock of fresh water.
Reporting in the journal Nature Geoscience this week, the investigators from the British Antarctic Survey (BAS), In Cambridge, England, describe the finding as "unique."
It extends the range of known volcanism in Antarctica by some 500 km and raises the question whether this or other sub-glacial volcanoes may have melted so much ice that global sea levels were affected, they said.
The volcano, located in the Hudson Mountains, blew around 207 BC, give or take 240 years, according to their paper.
Anomalous radar readings
Evidence for this comes from a British-American airborne geophysical survey completed between 2004 and 2005. This used radar to delve deep under the ice sheet to map the terrain beneath. The team spotted anomalous radar reflections over 23,000 square kilometres - an area bigger than Wales.
They interpret this signal as being a thick layer of ash, rock and glass, formed from fused silica, that the volcano spewed out in its fury.
The amount of material – 0.31 cubic kilometres – indicates an eruption of between three and four on a yardstick called the Volcanic Explosive Index (VEI).
By comparison, the eruption of Mount St. Helens in 1980, which was greater, rates a VEI of five, and that of Mount Pinatubo in 1991 is a VEI of six.
Choices
A man and his family buy a nice little house on a piece of land overlooking the coast. They immediately decide they need an addition. They figure the addition would make more sense on the back of their house, but the building inspector warns them that building the addition in the back is more risky because it’s getting awfully close to the cliff at the back of their yard. He suggests building it in the front of the house. They nonetheless build it out back. Several years later they decide on another addition, and once again the building inspector warns them of building it in the back. He tells them their plan is to build the addition right on the edge, and asks them why they would tempt fate when they have a huge area out front….
Does it really matter who is right here? Maybe the guy can build a third addition, perhaps even a fourth, but one of these days part of his house is likely going down the cliff…and all he had to do was build in a different direction.
Now it was asked: How can any intelligent person argue against decreasing our burning of fossil fuels, especially scientists?
Scientists said that lead in gasoline was perfectly safe.
Scientists said smoking is harmless.
Scientists said asbestos was fine.
Scientists today tell us that aspartame and fluoride and genetically modified foods are safe.
Scientists are just as greedy as everyone else, that’s how.
Scientific data can often be used to prove both sides of an argument, so be careful of statistics and such that are obviously biased towards corporate interests.
Look around. Since 1992, there has been a steadily increasing amount of scientific warnings and sense of urgency regarding the environment. There has been a rise in atmospheric carbon dioxide and global temperature. Fisheries around the world have collapsed. We bear witness to species destruction, extinction and habitat destruction, toxic pollution of air, water and soil, and lack of clean fresh water. And at the same time, we see poverty and inequity on a massive scale. While production increases, while trade and commerce increase, while wealth increases, so does poverty, because you see wealth and poverty don’t just live together shamefully in contrast; they’re there in a dynamic interrelationship, because it is wealth that creates poverty. And so we see a world where the rich are getting richer and the poor are getting poorer. Environmentalists struggle rightly to protect endangered species and threatened habitats and ecosystems but when half the world struggles to survive on two dollars or less a day, the obscenely wealthy nations of North America, Europe and East Asia continue to demand more and more steady growth.
We are now approaching that cliff face rapidly, and we’ll be hanging over it soon enough, ready to tumble at any moment. It is well past the time to begin building in a new direction. And that new direction must surely be sustainable and ecologically sound, unlike the hydrocarbon economy we have built now.
It's sure getting cold!
I recently watched a documentary on the National Geographic Channel. It was about a scientist that drills thousands of feet down into arctic ice to examine ice layers, and determine how our past climate were like.
To his astonishment, he concluded that the last 10,000 years has been abnormal in terms of calmer climate. This in turn might have given rise to the growth of mankind in a much stable environment where we didn't have to expend too much energy just to survive, and could involve ourselves in other creative endeavors that increased our knowledge, and intelligence.
What we are seeing now with all the crazy weather, is probably the climate moving to a more normal state.
There's global warming, then there's global cooling, then there's global warming, then there's global cooling. What we should all do is relax, and know that this is all just part of the norm!
I prefer global warming because I heard that plants, and animals thrive when the climate is warmer, and I could use a tan if I said so myself!