Volcano blows hole in global warming fight
A volcanic plume of iron-laden ash from a 2008 Alaskan volcano eruption led to an unprecedentedly huge bloom of photosynthetic ocean plankton that fed off the ash, researchers have found.
This natural phenomenon is much like a geoengineering scenario proposed by some researchers who want to fight global warming by spurring the growth of marine plants that can suck carbon dioxide from the air.
However, this massive bloom of plankton resulted in only a modest uptake of atmospheric carbon dioxide, the researchers said, seemingly dealing another blow to such geoengineering schemes.
Hamme and her colleagues estimated that this massive plume only absorbed about 4 million tons (37 billion kg) of carbon dioxide. While this might sound like a lot, the burning of fossil fuels releases nearly 7,000 times as much carbon dioxide annually at about 26.4 billion tons (24 trillion kg) a year, while the oceans naturally absorb about 8.1 billion tons (7.4 trillion kg) of carbon dioxide annually.
“Despite the huge area of iron addition and the optimal time of year when there was plenty of sunlight, the impact of this August 2008 event in terms of carbon dioxide absorption was quite small,” Hamme said. “This tells us that iron fertilization would have to be performed on a truly gigantic scale to have an impact on our climate.”
Geo-engineering schemes to address CO2 are likely to fail, because the scale required would cost so much no-one will want to do it. This is besides the tricky problem of un-known consequences.