Explosive volcanic eruptions might be attention grabbing, but a new review of research finds that their environmental impact pales in comparison to human activities. According to the research, humans put out the same amount of carbon dioxide in three to five days that all of the volcanoes on Earth put out in one year.
"Anthropogenic carbon dioxide emissions dwarf global volcanic carbon dioxide emissions," study researcher Terrance Gerlach, of the U.S. Geological Survey, said in a statement. Carbon dioxide, or CO2, is the main greenhouse gas responsible for climate change.
Gerlach crunched the carbon dioxide numbers from earlier studies of volcanic output, finding a range of 0.13 to 0.44 billion metric tons, or gigatons, of CO2 per year. In comparison, the estimated rate of human carbon dioxide emissions for 2010 alone is 35 billion metric tons.
Land-use changes: 3.4 gigatons per year
Light-duty vehicles (mainly cars and pickup trucks): 3.0 gigatons per year
Cement production: 1.4 gigatons per year
In fact, to scale up volcanic emissions to an equivalent of what we release would require the release of more than 200 cubic miles (850 cubic kilometers) of magma per year, the researchers calculate. For comparison, Lake Ontario holds about 393 cubic miles (1,640 cubic km) of water.