Effects of volcanoes on climate change
Friday 28, May 2010
The eruption of the Eyjafjallajökull volcano in Iceland is the latest in a series of volcanic events across the globe. But what effect do volcanoes have on our climate?
A double impact
We know volcanoes emit two gases which can have an impact on global temperatures — sulphur dioxide and carbon dioxide (CO2). They each have very different effects and work on different timescales:
Case study — Mount Pinatubo, Philippines
Recent history has given us a good case study of the impact of a large volcanic eruption. Mt Pinatubo in the Philippines erupted in 1991, marking one of the biggest volcanic events of the 20th century.
It put about 20 million tonnes of sulphur dioxide into the stratosphere. As we’d expect, this impacted global temperatures. The average for the following year was reduced by between 0.1 °C and 0.2 °C, although temperatures quickly recovered the year after.
A large amount of CO2 was also emitted, with an estimated 250 million tonnes being put into the atmosphere. This is a significant amount, but is still much smaller than produced from human activity, such as burning fossil fuels and changing land use, which is estimated to put out about 26,000 million tonnes of CO2 a year.
So far (May 2010), the indications are that the recent eruption in Iceland won’t have a significant impact on our climate. Compared to an eruption such as Mt Pinatubo, Eyjafjallajökull has been very small. The quantities of both sulphur dioxide and CO2 emitted are far smaller, and are unlikely to have a discernable impact.
Volcanoes, human activity and climate change
The effect of volcanoes on our climate has led some to doubt human impact on climate change. For example, it has been suggested volcanoes put out more CO2 than human activity, but this is not the case.
In an average year, volcanoes put out an estimated 100—130 million tonnes of CO2 globally. Estimates suggest human activity puts out more than 2,000 times as much — about 26,000 million tonnes of CO2 per year.
Volcanic activity has been fairly consistent over a long period of time. While there are some major eruptions which cause brief changes in climate, the amount of CO2 in the atmosphere has balanced out fairly quickly due to natural cycles.
The 35% increase in CO2 which has been observed over the last century is believed to be unprecedented, and the only plausible explanation for that increase is human activity. All the evidence suggests it is this increase in CO2 which is magnifying the greenhouse effect and causing our climate to change.
More and more travellers think that researching and planning a European city break is half the fun and they're not interested in pre-arranged trips or escorted tours. Self-guided tours offer a lot of advantages but require some guidance and good resources.
With the recent wild fires, disrupting flights and increasing air pollution, environmental quality is a growing factor in attracting tourists.
The hotel price comparison site www.trivago.co.uk has put together a list of the fifteen most spectacular hotel rooftop terraces in the world.