Posted on 10/02/2014 2:08:23 PM PDT by Ernest_at_the_Beach
From the National Post Is it volcano season? From Japan to Iceland, scientists probe the reasons why there are so many eruptions lately
Eruptions caused by climate change
In recent decades, it has become apparent that the consequences of planetary ice loss might not end with rising sea levels. Evidence has been building that in the past, periods of severe loss of glaciers were followed by a significant spike in volcanic activity.
Around 19,000 years ago, glaciation was at a peak. Much of Europe and North America was under ice. Then the climate warmed, and the glaciers began to recede. The effect on the planet was generally quite favourable for humankind. But, since the mid-1970s, a number of studies have suggested that, as the ice vanished, volcanic eruptions became much more frequent. A 2009 study, for example, concluded that between 12,000 and 7,000 years ago, the global level of volcanic activity rose by up to six times. Around the same period the rate of volcanic activity in Iceland soared to at least 30 times today’s level.
There is supporting evidence from continental Europe, North America and Antarctica that volcanic activity also increased after earlier deglaciation cycles. Bizarrely, then, volcanic activity seems — at least sometimes — to rise and fall with ice levels. But why? Again, this strange effect might come down to stress.
Eruptions cause by the melting of ice
Ice sheets are heavy. Each year, Antarctica’s loses around 40 billion metric tons of ice. The sheets are so heavy, in fact, that as they grow, they cause the Earth’s crust to bend — like a plank of wood when placed under weight. The corollary of this is that, when an ice sheet melts, and its mass is removed, the crust springs back. This upward flexing can lead to a drop in stress in the underlying rocks, which, the theory goes, makes it easier for magma to reach the surface and feed volcanic eruptions.
The link between climate change and volcanism is still poorly understood. Many volcanoes do not seem to have been affected by it. Nor is it a particularly pressing concern today, even though we face an ice-free future. It can take thousands of years after the glaciers melt for volcanic activity to rise.
Yet while it may not be an immediate hazard, this strange effect is a reminder that our planet can respond to change in unforeseen ways. Contrary to their brutish reputation, volcanoes are helping scientists understand just how sensitive our planet can be.
h/t to reader Cam_S
They are equating the loss of mile thick ice sheets with the very small reductions of ice cover (if it’s happening) we may be seeing today. This is an argument in search of a problem. For the most part, volcanos are the result of sea floor subduction at plate margins. There are also hot spots which remain poorly understood but which show no sensitivity to climate. Sounds like the bloviating of a charlatan to me.
Nice list,
Why not both?
Gay meter pegged to right.
Let's just leave it at that.
Around 19,000 years ago, glaciation was at a peak. Much of Europe and North America was under ice. Then the climate warmed
And it was all the Fault of HUMAN GREED /s
Bingo! And, the very suggestion of such a mechanism, whether it exists or not, is a reminder that the earth's climate, besides being governed by non-linear dynamics, and thus insusceptible to long-term prediction, is an open system with unknown inputs, which make long-term prediction even more dubious.
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