[url=http://www.abc.net.au/science/articles/2011/06/28/3255476.htm]Humans dwarf volcanoes for CO2 emissions[/url]
Volcanoes are spectacular displays of the massive forces at work inside our planet yet they are dwarfed by humans in at least one respect: their carbon dioxide emissions.
Despite statements made by climate change deniers volcanoes release a tiny fraction of the amount of carbon dioxide emitted by human activities every year.
In fact humans release roughly 135 times more carbon dioxide annually than volcanoes do on average according a new analysis. Put another way humans emit in under three days the amount that volcanoes typically release in a year according to the best estimates of volcanic emissions.
“The question of whether or not volcanoes emit more CO2 than human activity is one I get more than any question in my email from the general public” says Dr Terrence Gerlach a retired volcanologist formerly with the Cascades Volcano Observatory part of the US Geological Survey.
To lay out a clear answer Gerlach compiled the available estimates of CO2 emissions from all global volcanic activity on land and undersea and compared them with estimates for human emissions. He published the compilation in Eos a publication of the American Geophysical Union.
“A lot of climate sceptics claim that volcanoes emit more CO2 than humans do” says Gerlach.
One example of these sceptic’s claims is the 2009 book Heaven and Earth: Global Warming the Missing Science by Professor Ian Plimer of the University of Adelaide.
“The main reason I think that this myth persists” says Gerlach: “First of all the emissions [from volcanoes] are extremely spectacular. When people see volcanic eruptions on television and it’s awesome and it’s very easy for people to imagine that huge amounts of CO2 are being emitted to the atmosphere.”
“However these spectacular volcanic explosions that are so stunning on TV last only a few hours” he says. “They are ephemeral. In contrast the sources of anthropogenic CO2 (smokestacks exhaust pipes etc) are comparatively unspectacular commonplace and familiar and in addition they are ubiquitous ceaseless and relentless. They emit CO2 24/7.”