We currently report subzero temperatures in the double digits and my drinks come frozen from the balcony. That makes it a little hard to write about the melting Arctic ice cap and what it means for e.g. polar bears and sea life. But one thing to remember is that weather and climate are two different things.
And that the climate is changing … well, once upon a time when I was a kid – felt millennia ago, really – the caretaker of my school would come winter arm himself with a garden hose and would sheath part of the sports field with ice. We were able to skate and slide on this makeshift rink for about two months. We also had a sledge and we used it. Not on ski vacation in theAlpsbut in the park around the corner. In recent years temperatures below freezing have lasted maybe two weeks tops in a row and snow was scarce.
ThoughBerlinis further north than all of theUSexceptAlaska, we are still far away from the Arctic cap. Yet, the global rise of temperature over the years is just that – global. Come summer the sea ice and also the ice sheet onGreenlandare melting. They always have done this, but never to the amount scientist measure today.
Since the introduction of satellite technology the area is closely monitored and data is collected and interpreted in papers like the IPCC Fourth Assessment Report and the Arctic Climate Impact Assessment. This is because theArcticshows an amplified response to global warming and is therefore seen as a high-sensitivity sensor for climate change – much better than my childhood ice rink. Projections based on this data suggest that theArctic Ocean will likely be free of summer sea ice sometime between 2060 and 2080, while another estimate puts this date at 2030.
So, less ice in theArctic– what’s the big deal? Methane, a potent greenhouse gas that is enclosed in the ice, is released into the atmosphere. Permafrost regions like the Siberian tundra defrost. The ocean circulation patterns might change. Knowing that the European weather is heavily influenced by the warmGulf Stream, the idea is kind of disturbing. The productivity of Phytoplankton is boosted, what could have results on the global carbon cycle. And last but not least we have to speak about polar bears.
Knut might have been born and raised in the captivity of the Berlin Zoo, yet the natural habitat of polar bears lies within theArctic Circle. Though most of the bears are born on land, they spend most of their life on sea – or to phrase it better on sea ice. That’s their ecological niche. That’s what their body has adapted to. They hunt their preferred food of seals from the edge of the sea ice and live off their fat reserves, when no sea ice is present. The decline of sea ice endangers their habitat and therefore their species. Today they are classified as a vulnerable species. If nothing changes, soon Knut’s is all we will have left.