Climate Change: Volcanic vs. Anthropogenic Carbon Dioxide

Reader Contribution by Richard Hilderman and Ph.D.
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In the past two years there have been major volcanic eruptions in Iceland that have ejected ash and carbon dioxide into the atmosphere. These eruptions have led some people to speculate that volcanic carbon dioxide emissions are far greater than the emissions produced by human activity. This would suggest that human induced release of carbon dioxide from the burning of fossil fuel plays an insignificant role in the current global warming trend. However, scientific data does not support this school of thought.  

The annual anthropogenic carbon dioxide emissions exceed the annual volcanic emissions by two orders of magnitude! Global carbon dioxide emissions from volcanoes is 0.13 to 0.44 billion metric tons (gigatons) per year while the 2010 anthropogenic carbon dioxide emission is estimated to be 35 gigatons. Clearly, volcanic carbon dioxide release is insignificant when compared to anthropogenic release. Indeed, the annual amount of carbon dioxide released by volcanoes is equivalent to the amount released by two 1000 megawatt coal-fired power plants (0.22 gigaton per year) which is just 2 per cent of the world’s coal-fired electricity generating capacity.

It is also important to keep in mind that carbon dioxide emitted from volcanoes is part of a natural process which recycles carbon between long and short term reservoirs. Volcanic emitted carbon dioxide comes from the long term reservoir and is used to restore carbon in the short term reservoir. To maintain a global temperature and ocean pH suitable for life the planet must regulate the amount of carbon dioxide in the short term reservoir. Carbon dioxide found in the short term reservoir is also utilized by plants during photosynthesis and is part of the shells of various marine organisms (my posting entitled The Carbon Cycle).    

On the other hand, burning of fossil is considered an unnatural release of carbon dioxide because this carbon dioxide enters the short term reservoir and overwhelms/disrupts the planet’s ability to cycle the excess carbon into the long term reservoir. This excess carbon dioxide is responsible for the greenhouse effect and thus global warming. In addition, some of the excess carbon dioxide enters the ocean and contributes to ocean acidification (my postings entitled Solar activity, Greenhouse Gas Levels and Climate Change on Our Earth and Atmospheric Carbon Dioxide Levels and Ocean Acidification).

We can’t continue to use volcanic carbon dioxide emissions as an excuse for our failing to curtail the use of fossil fuel.

Photo Credit: Fotolia/Beboy