English: The Heinabergsjökull in Iceland is an outlet glacier flowing from Vatnajökull, the largest ice cap in in Europe by volume (3,100 km³). All over the world the ongoing retreat of glaciers is one of the clearest manifestations of recent global warming, associated with rising greenhouse gas concentrations. Glaciers in Iceland owe their existence to a maritime climate and they are located in mountainous areas where precipitation is highest. Especially these glaciers are sensitive to climate change and respond rapidly by advancing or retreating. The Vatnajökull has decreased by about 3% in volume in the last 10 years. One of the side effects is the continuous decreasing amount of counter-pressure. As the amount of weight on the Earth’s crust changes, geological stresses inside the crust will also change, the crust will bounce up again, increasing the likelihood of eruptions. But it’s not just unloading the crust that triggers volcanic activity. Another element, the loading part, is the effect that rising sea levels – also a consequence of melting ice caps – will have on volcanoes. Scientists expect that we are going to see a massive increase in volcanic activity globally, with distinctive climate effects. The eruptions of the Eyjafjallajökull in 2010 and the Bardarbunga last year, were the first impressive forerunners.