Volcanic activity in Iceland has risen dramatically over the past few weeks.
Yet, thankfully, the big eruption many feared never materialized and signs show that the pressure has been subsiding. Good news, many among us may think.
Yet science journalist and geologist Axel Bojanowski at Spiegel warns that there’s still enough to worry about. According to Bojanowski concentrations of sulfur dioxide (SO2) have “never been higher since measurements began in the 1970s“. The amount of SO2 emitted by the recent volcanic activity is surpassed only by the “largest of eruptions”.
What’s more, Bojanowski adds:
Seldom does so much sulfur gas get into the air. It could even cool the climate.”
Photo number 12 of Spiegel’s spectacular photo series here is a NASA computer model simulation depicting the spread of the sulfur dioxide cloud over Europe. The growing concentration of sulfur dioxide is a reason for “more concern”, Spiegel reports. High concentrations of sulfur dioxide in the air are corrosive and pose a threat to human health. Bojanowski writes:
Gradually it is posing an additional threat: to the climate. The emitted amounts of gas have already reached historic dimensions, reports the country’s environmental authority, the Icelandic Environmental Agency. Daily up to 60,000 tonnes of SO2 are released from the lava chasm.”
Bárdarbunga has already emitted approximately two million tonnes of SO2. Only the largest eruptions surpass this amount.”
Bojanowski adds that although the SO2 haze in the atmosphere is not visible to the naked eye, it is seen by NASA satellite, and it extends over parts of Europe. SO2 is an effective sunblock that acts to cool the atmosphere. Spiegel also describes the Laki eruption of 1783 and 1784, which led to a marked cooling and European crop failures.
According to Spiegel, Bárdarbunga eruption and gas emission is nowhere near on the same scale as Laki, which spewed 122 million tons of SO2 into the atmosphere. But Spiegel compares Bárdarbunga’s 2 million tons of SO2 to other major 20th century volcanic eruptions: El Chichon (7 million), which was enough to cause cooling globally. Pinatubo spewed 20 million tons and cooled the planet by 0.5°C for two years.
Though Bárdarbunga’s SO2 so far has not been shot up into the stratosphere, Spiegel warns that “two factors could make the volcano’s impact detectable: At high latitudes such as those of Iceland, the stratosphere is several kilometers lower than in the tropics, thus allowing the gas to reach it more quickly. Also chasm eruptions such as those at Bárdarbunga produce hot air upward currents over the volcano, which can carry the gases up to the stratosphere.”
Note that the SO2 gas has been carried in the air over to the European continent. Though Bárdarbunga’s SO2 may not have any real impact on cooling the planet, it certainly will not help to warm it either.