Volcanic numbers10 countries with the most volcanoes.[1]
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A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.[2]
Volcanic activity
According to the National Museum of Natural History’s Global Volcanism Program, more than 1,500 volcanoes on the planet have erupted at some point in the last 11,500 years, the current geological epoch otherwise known as the Holocene period.[1]
Global warming
A 2017 study published in the Geology journal researched a link between melting glaciers and ice caps and an increase in volcanic activity. Looking at a period of cooling about 5,500 years ago in Iceland, the researchers found that growing ice coverage coincided with a decrease in eruptions. The same was true in reverse: when the ice retreated, the number of eruptions increased. As the world’s ice sheets shrink and glaciers melt, it has been suggested the retreat could usher in a new era of volcanic activity.[1]
Oppenheimer
- Increased activity
Clive Oppenheimer, professor of volcanology at the University of Cambridge, says there has not been an increase in volcanic activity.[1]
- “There have been quite a few eruptions in the news lately, so people question whether there’s an increase in rates of volcanism that we’re seeing just now, and this isn’t really the case,” he said.
- “Eruptions are happening all the time - some make the news headlines and others don’t.
- “If we look at the statistics back in time, the main thing we see is a reporting bias. There are not many eruptions during World War Two, for example, when people had other things to really worry about.
- “So of course things will flare up in one place or another place and then it will be very much how those eruptions affect people and where abouts in the world [as to] whether that then becomes newsworthy.”
- Global warming
Oppenheimer explained the link between ice ages and rates of volcanism.
“We do see effects with deglaciation of the last ice age with the relatively sudden unloading of volcanic regions that might have been under two to three kilometres of ice,” he said. “When that is moved that can cause melting that fuels volcanoes, it can trigger eruptions, and that leads us to the question well then what about the future, as we are seeing global warming and more deglaciation.
“But it’s something one could only really study from the point of view of models perhaps, but also from statistics so you’d really want lots and lots of data.
“I think we can kind of do that when we look back at the end of the last ice age, but as we’re going forward in the next century, I don’t think we will see any kind of statistical blip related to anthropogenic climate change today.”