The October 1996 eruption within the Vatnajökull Glacier lasted for 13 days, with 3 km3 of ice being melted at the eruption site. The 0.4 km3 of erupted basaltic – andesite magma fragmented into glass, forming a hyaloclastite ridge 6 – 7 km long and 200 – 300 m high under 500 – 750 m of ice. The minimum concentration of exsolved CO2 in the 1x10^12 kg of erupted magma was 516 mg/kg, for S it was 98 mg/kg, for Cl it was 14 mg/kg, and for F it was 2 mg/kg. The pH of the melt water at the eruption site ranged from about 3 to 8. The volatile and dissolved element release to the meltwater in less than 35 days amounted to more than 1 million tonnes. The meltwater flowed from the eruption site into the Grímsvötn subglacial lake under a 270-m-thick ice cover. The total dissolved flux was 1 million tonnes and the minimum C flux was equal to 0.6 million tonnes of CO2. The annual magmatic flux of CO2 to the atmosphere and surface waters in Iceland, mostly long-term degassing through volcanoes and geothermal systems, has been estimated to be of the order of 1 – 2 million tonnes (Arno ́ rsson and G ́ıslason, 1994). Volcanic eruptions are frequent in Iceland, about one every fifth year (Thorarinsson, 1981). Thus, a small eruption like in 1996 contributes 5 – 10% to the total annual CO2 magmatic flux from Iceland.