Volcanic eruptions can affect the climate. Huge eruptions release millions of tons of sulphur dioxide into the air which then remains in the atmosphere for a few years, reflecting sunlight away from the earth and cooling down the planet.
Now new evidence suggests that the relationship can work in the opposite direction, meaning that changes to the climate can have an effect on volcanic eruptions; linking the two events even more.
A recent study by geologists has found a pattern that suggests large eruptions tend to occur every 41,000 years, a number very well known to paleoclimatologists. This is because every 41,000 years the Earth axis changes, tilting gradually forward, then backward. This change is called ‘Obliquity’ and is one of the three ‘Milankovitch Cycles’ that happen over huge periods of time and influence the climate.
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Scientists have suggested that these changes in the Earth’s axis may have a big effect on ice ages. Much as with our seasons, when the Earth tilts away from the sun it is winter, and towards the sun heralds summer. This long term axis cycle acts as an exaggeration of this effect. So when the earth tilts further away from the sun on it axis, the winters become more aggressive, and eventually they join together forming an ice age, because the summers are not warm enough to melt the winter ice and snow.
As an ice age starts to form, vast quantities, and therefore weight, of water moves from the oceans up onto the continents as mile thick ice sheets form, then as the ice age starts to end the water, and weight, returns to the oceans. The movement of this weight compresses the continental plates and shifts the magma below the Earth’s mantle leading to far more eruptions.
By. Joao Peixe of Oilprice.com
Joao is a writer for Oilprice.com