Author: Xabi Otero
•1:47 PM
So many Climate changes have taken place throughout the history, and they've been very different. But it's amazing to read that an Icelandic volcano was the reason of a climate change that later spreads to most of the Northern hemisphere.

Icelandic volcanoes were under an icy layer, which are called glaciers, but the magma inside the volcanoes tried to go out the surface, and this fact repeatedly make glaciers dissapear. If we see the glacier from above (as we can see in the most important one, Vatnajökull), we can notice a concave form.

Once the glaciers have disappeared, the eruptions are harder, as the upper layer's already dissapeared. For example, Icelandic people would never forget the hard eruption of the Laki volcano in 1783. Then, the crops were burnt and animals were killed too, so there was a great famine in the whole country.

It seems that after that eruption (And the following 4 ones 3 years later), there was a climate change, specially in the Northern Hemisphere, but it wasn't known whether both facts were related. In order to prove that probable relationship, they tried to find the answer in the 4 eruptions which took place 3 years later. Then, lava went out for 8 months from the fissures (Icelandic volcanoes are very similar to the Hawaiians ones, because lava goes out from a fissure).

The geologists nowadays have found the answer in the rocks. The ones we can find around Laki are full of holes, and that means once magma ebaporated from there. In addition, as we can also see white marks, those are pure magma's rests. So, if we could analyze their composition, we could know the composition of the magma and they knew it was very rich in sulfur oxide.

Sulfur oxide later went up to the atmosphere and mixed with water vapour, creating a big fog. Then, that amazing cloud didn't let the sun arrive with so much strength (so, this is one reason of the descent of the temperatures). Moreover, we can't forget fog, like a cloud, has the capacity of reflecting the sun's rays, so a part of the sun's rays that reach that fog, came back to the atmosphere again. That's why the amount of radiation that reach the surface was extremely few and the tenperatures in Iceland went down 0'5 - 1º on average. Later, that fog spread to many countries in Northern - Central Europe, so there they also had colder climate. Although the descent of the tenperatures was quite little, it was enough to create a bigger layer of ice in winter, and as a result, when the ice layer fused in spring, floods abounded.

Those eruptions also had more consequences (the Indian drought, the Japanese colder winters...), but I guess this is enough.
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