How Volcanoes Affect our Climate

Had you been around in 1815 somewhere near Indonesia you would have seen one of the earth’s most terrifying spectacles. The largest volcanic eruption for centuries. The volcano Tambora blew its top and emitted vast amounts of ash and lava, created a Tsunami and killed tens of thousands.

However, its effects were not only felt locally. It was this volcano and not the battle of Waterloo in which Napoleon was finally defeated that that really changed the course of history. Why? Because it changed our climate, our weather and our food production – around the globe. It shows you how volatile our climate system is.

When a volcano erupts, it emits lava, ash and gases into the atmosphere. The gases stay in the atmosphere for years and travel around the world. They shield the earth against some of the sunlight, reflecting it back into space. It is the opposite of global warming. A single large volcanic eruption can lead to years of global cooling, shifting important weather patterns such as the monsoons.

A colder climate also leads to less rainfall. This can hit very different regions around the world. In the case of the volcano Tambora, it led to food shortages and starvation in Europe, China and the US in the following year 1816. Winters went on much longer and the summers were cold.

What Happens, If a Large Volcanic Eruption Occurs Today?

More recent eruptions like Pinatubo in the Philippines or Mount St. Helena in the US were small in comparison with Tambora. At the same time, the Tambora eruption was small as compared to some volcanic eruptions thousands of years ago. How do we know? We can measure the amount of certain chemical substances emitted by volcanoes in the Arctic and Antarctic ice shields. These are our climate history books.

So: it can, potentially get much worse. Remember, according to one theory, it was a volcanic eruption that killed the dinosaurs, which had lived for millions of years. The good news is: we are getting better at monitoring our volcanoes.

Volcanoes: The Ring of Fire

The most active volcanic region is the Pacific rim, a so-called “ Ring of Fire” stretching from Chile to Mexico and Hawaii on the American side and then via Alaska to Japan, the Philippines, Indonesia and the Southern Pacific on the Asian side. If things really blow up, it will likely be somewhere here.

Researchers are keeping a close watch on the activities of most known volcanoes. Many of them will show signs of a looming eruption in the form of smaller eruptions or puffs of smoke. However, some of them don’t… And if we witness a really major eruption, that will impact the world’s climate and food supplies, then even advance notice will not be of much help.

The Costs of Volcanic Eruptions

Luckily, it’s not very likely that we will experience such a catastrophic volcanic eruption in our lifetime. However, even the more normal eruptions we know, will come at steep costs.

The planet is more densely populated today than ever before. Evacuating local populations could thus become challenging. The economic costs will also be very high. Do you remember, when a small volcano in Iceland interrupted the air traffic between Europe and the US for days? It cost the airline industry around $ 2bn. On the positive side, we are also more resilient today: our food production covers many parts of the worlds and trade ensures that few corners of the planet are isolated.


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Tobias Engelmeier
Tobias Engelmeier
Tobias Engelmeier is an entrepreneur and very passionate about the climate, sustainability, solar energy and India. He is a German Indophile. You can find out more about Tobias on and on LinkedIn. He is also active on Twitter (@TEngelmeier).
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