By Gary Thomas
Geothermal Energy from
Sources and Further Reading
A volcanic eruption is one of the most awe-inspiring sites in
nature, but these phenomenal natural events are seen as a danger on a
grand-scale. Volcanic eruptions can devastate whole communities, cause
death and destruction and even render entire islands almost
uninhabitable. They have also been blamed for global warming. But are
volcanoes really all that bad? This article explores how much volcanoes
contribute to climate change, and whether they can contribute
significantly to clean technology.
The monumental eruption of Mount Pinatubo,
Philippines on June 12, 1991. Image Credit: USGS,
When a volcano erupts, it releases billions of tonnes of gas into
the atmosphere, some of which can have a drastic impact on the global
climate. Sulphur dioxide is released into the atmosphere which can lead
to global cooling and carbon dioxide is also released which can lead to
Some people are under the impression that volcanoes emit more CO2
per year than human activity, and are therefore a bigger threat
to global warming. However, it has been proved time and time again this
that is simply not true. In fact, it has never been show that
contemporary volcanic eruptions have caused any degree of global
warming. It is debated that large scale volcanic activity could have
caused short-term global warming in the past, and even contributed to
mass extinctions such as the end of the dinosaurs, but nothing on this
scale has been experienced in recorded history.
Studies show that the amount of CO2 released by volcanoes
each year is less than 1% of the CO2 emissions caused by
human activities. In an average year, all volcanoes erupting on Earth
will collectively emit a maximum of 0.26 billion metric tons(Gt) of CO2.
This may sound a lot, but it is dwarfed by the 35Gt currently released
by humans every year-and this is ever increasing. Even some of the
largest volcanic events in history, such as the eruptions of Mt. St.
Helens, 1980 (0.01Gt of CO2) and Mount Pinatubo, 1991
(0.05Gt of CO2) would barely be felt amongst the total
A slightly more viable concern is volcanoes contributing to global
cooling. The sulphur dioxide emitted by a volcano is converted into a
fine aerosol of sulphuric acid in the atmosphere, which reflects
sunlight back into space, leading to cooler temperatures.
A famous historical example of this occurred when the craters of
Laki in Iceland erupted, between 1783 and 1784. This eruption was the
second largest in the last thousand years and spewed out an estimated
120 million tons of sulphur dioxide, along with around 8 million tons
of hydrogen fluoride. This cloud of gas rose high into the atmosphere
and spread across Europe, causing widespread devastation. Many people
died as a direct result of this gas, due to the sulphur dioxide mixing
with water vapour and choking people to death.
The eruption also caused wild fluctuations in the climate of Europe:
In Britain, the July of 1783 was the warmest month ever recorded.
However, the worst consequence of the eruption was the following winter
which was the most severe in recorded history, with major crop failures
and loss of livestock. As a result, a 5th of the population of Iceland
was wiped out, along with many thousands across Europe.
There are similar examples dotted throughout history. The eruption
of Mount Pintubo in 1991 threw so much SO2 into the
atmosphere that the Earth cooled by 1.3oC, and the effect
was felt for years afterwards.
Though unlike CO2 the SO2 emissions of a
volcanic eruption do have a measurable effect on the climate, these
affects are short-term and do not affect overall warming trends over
decades or centuries, let alone millions of years.
So if volcanoes are not causing global warming, is it possible they
could help us to prevent it? Recent research has shown that it may be
possible to harness the immense geothermal energy produced by volcanoes
and use it as a renewable fuel source, thus cutting the worlds
dependence of CO2-producing fossil fuels.
MIT has presented research that suggests that if even 2% of the
heat below the Earth’s volcanoes is harnessed, it could provide enough
energy for the entire United States 2500 times over. Furthermore,
unlike solar and wind power, this geothermal energy is not reliant on
Knowing that the energy is there is one thing, but actually
harnessing it in a safe and consistent way is a very different
prospect. The favoured method of accessing this energy currently is
EGS, or Enhanced Geothermal Systems. . This involves pumping millions
of gallons of water into dormant volcanoes via wells, which is then
heated by the thermal energy under the volcano. Once this water has
been heated to extremely high temperatures, it is transported to the
surface where the heat energy is then extracted.
One of the major issues is whether enough water can be pumped
through the system to make this form of energy economically viable.
Another major concern is whether the ‘hydroshearing’ used to create the
wells will lead to earthquakes. This is still somewhat an unknown
quantity and so the jury is still out on whether volcanoes can becomes
man’s new best friend.
Sources and Further
Volcanos the New Sources of Geothermal Energy? Energy Digital,
Plus Side of Volcanoes: Geothermal Energy USGS
do volcanoes affect the climate? The Guardian
Gases and Climate Change Overview USGS
The eruption that
changed Iceland forever BBC News Magazine, 16/04/10