Re: In other words, "When to act"
"when all of humanity's emissions for decades is outdone by a single volcano in a week, tanking the income of a thousand families is stupid."
No. Completely untrue - see this USGS page: http://volcanoes.usgs.gov/hazards/gas/climate.php
"The published estimates of the global CO2 emission rate for all degassing subaerial (on land) and submarine volcanoes lie in a range from 0.13 gigaton to 0.44 gigaton per year (Gerlach, 1991; Varekamp et al., 1992; Allard, 1992; Sano and Williams, 1996; Marty and Tolstikhin, 1998). The preferred global estimates of the authors of these studies range from about 0.15 to 0.26 gigaton per year. The 35-gigaton projected anthropogenic CO2 emission for 2010 is about 80 to 270 times larger than the respective maximum and minimum annual global volcanic CO2 emission estimates. It is 135 times larger than the highest preferred global volcanic CO2 estimate of 0.26 gigaton per year (Marty and Tolstikhin, 1998).
In recent times, about 70 volcanoes are normally active each year on the Earth’s subaerial terrain. One of these is Kīlauea volcano in Hawaii, which has an annual baseline CO2 output of about 0.0031 gigatons per year [Gerlach et al., 2002]. It would take a huge addition of volcanoes to the subaerial landscape—the equivalent of an extra 11,200 Kīlauea volcanoes—to scale up the global volcanic CO2 emission rate to the anthropogenic CO2 emission rate. Similarly, scaling up the volcanic rate to the current anthropogenic rate by adding more submarine volcanoes would require an addition of about 360 more mid-ocean ridge systems to the sea floor, based on mid-ocean ridge CO2 estimates of Marty and Tolstikhin (1998).
There continues to be efforts to reduce uncertainties and improve estimates of present-day global volcanic CO2 emissions, but there is little doubt among volcanic gas scientists that the anthropogenic CO2 emissions dwarf global volcanic CO2 emissions."
I think I can tell who's being stupid here.