Jul 4, 2014
Bishop Hill in Climate: carbon budget

Robin Wylie, an academic at University College London, has written a fascinating piece at Live Science on volcanic emissions of carbon dioxide, which is an area of geoscience that is, like so many others, characterised more by ignorance than understanding - only 33 of the known 150 "smokers" have been examined by scientists.

According to Wylie, the latest research suggests that volcanic emissions are many times what they were thought to be a couple of decades ago:

In 1992, it was thought that volcanic degassing released something like 100 million tons of CO2 each year. Around the turn of the millennium, this figure was getting closer to 200. The most recent estimate, released this February, comes from a team led by Mike Burton, of the Italian National Institute of Geophysics and Volcanology – and it’s just shy of 600 million tons. It caps a staggering trend: A six-fold increase in just two decades.

More remarkably, Wylie notes that there may be hundreds more volcanoes that are technically inactive but which are still emitting substantial quantities of carbon dioxide.

Even more incredibly, it even seems that some volcanoes which are considered inactive, in terms of their potential to ooze new land, can still make some serious additions to the atmosphere through diffuse CO2 release. Residual magma beneath dormant craters, though it might never reach the surface, can still 'erupt' gases from a distance. Amazingly, from what little scientists have measured, it looks like this process might give off as much as half the CO2 put out by fully active volcanoes.

Even with these new sources accounted for, I think that known volcanic emissions will still be much lower than anthropogenic ones, but the very fact that we are uncovering new sources suggest that we still have a lot to learn about natural carbon dioxide emissions.

Update on Jul 4, 2014 by Registered CommenterBishop Hill

In related news, a new satellite that will monitor atmospheric carbon dioxide levels has been launched. (H/T Peter Gill)

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