Icelandic ice caves are climate archives

This impressive ice cave inside the Svínafellsjökull glacier in Skaftafell, Iceland, is an astounding 50 m (164 ft) long, 10 m (33 ft) wide and 7 m (23 ft) high grotto.
Persistent cold spells in Iceland during wintertime offer rare opportunities to venture onto the frozen glacial lakes. At outside temperatures below -8°C (17°F) over a prolonged time period, the lagoons freeze over with ice thicknesses of more than 50 cm (1.6 ft). Such icy conditions also stabilize the otherwise very fragile ice caves to such an extent that a brief access can be risked.
However, the glacier itself does not slow down its flow during the cold season. Driven purely by gravity, the ice creeps down the slopes of the ice cap at a remarkable speed, reaching up to 1 m (3.3 ft) per day. The ice caves inside the glacier formed by meltwater discharge channels. They also follow this omnipresent movement. The access to this ice grotto unveils an enchanting fairytale world, accompanied by permanent, frightening and awe-inspiring crackling and crunching noises of the moving ice.
At the outer edge of the glacier, the ice has reached an age of about 1000 years. Several horizontal black layers run through the ice. These were deposited as ashes on the snow, when volcanoes erupted repeatedly under the ice cap. The ashes were covered by further snowfall events. Under its own accumulating weight and over time the snow was slowly compressed into glacial ice and began its long journey downhill. The deep blue color of the ice illustrates how much it is pressurized and compacted. It consequently contains few air bubbles that could scatter the light into a whitish color. The frozen bottom of the ice cave contains the meltwater stream that is in contact with the proglacial ice lagoon.
Standing inside this crystal grotto and enjoying the breathtaking view from the inside out against the yellow-red sky of the sunset was so overwhelming and aroused such emotions in me that this exhilarating feeling of awe, humility and admiration has been dwelling in me ever since.