29 September 2016, The Conversation, Record high to record low: what on earth is happening to Antarctica’s sea ice? 2016 continues to be a momentous year for Australia’s climate, on track to be the new hottest year on record. To our south, Antarctica has also just broken a new climate record, with record low winter sea ice. After a peak of 18.5 million square kilometres in late August, sea ice began retreating about a month ahead of schedule and has been setting daily low records through most of September. It may not seem unusual in a warming world to hear that Antarctica’s sea ice – the ice that forms each winter as the surface layer of the ocean freezes – is reducing. But this year’s record low comes hot on the heels of record high sea ice just two years ago. Overall, Antarctica’s sea ice has been growing, not shrinking. So how should we interpret this apparent backflip? In our paper published today in Nature Climate Change we review the latest science on Antarctica’s climate, and why it seems so confusing. Antarctic surprises. First up, Antarctic climate records are seriously short. The International Geophysical Year in 1957/58 marked the start of many sustained scientific efforts in Antarctica, including regular weather readings at research bases. These bases are mostly found on the more accessible parts of Antarctica’s coast, and so the network – while incredibly valuable – leaves vast areas of the continent and surrounding oceans without any data. In the end, it took the arrival of satellite monitoring in the 1979 to deliver surface climate information covering all of Antarctica and the Southern Ocean. What scientists have observed since has been surprising. Read More here
Category Archives: Antarctica
19 September 2016, The Conversation, Disruption over Macquarie Island calls for some clever Antarctic thinking. The fate of the Australian Antarctic Division’s research base on Macquarie Island hangs in the balance, after last week’s surprise announcement that it would close in March 2017 was followed on Friday by a suggestion that the government could yet reprieve it. Why all the fuss over a scattering of buildings on a windswept island (admittedly a UNESCO World Heritage-listed one) perched on a tectonic ridge halfway between Australia and Antarctica? Macquarie Island is the perfect natural laboratory for scientific research. Unique climate, geological, biological and astronomical measurements are collected year-round. The data is fed into many large-scale, international science programs and reports, including those published by the Intergovernmental Panel on Climate Change. It is something of an anomaly in Australia’s national Antarctic program. Unlike Heard Island, Macquarie Island lies outside the areas covered by the Antarctic Treaty and the Convention on the Conservation of Antarctic Marine Living Resources. The Tasmanian government manages the island. The buildings at the island’s north end are home to research infrastructure and accommodation for various organisations. These include the Tasmanian Parks and Wildlife Service, the Bureau of Meteorology, and the Australian Radiation Protection and Nuclear Safety Agency, which monitors the Southern Ocean for evidence of nuclear events. These buildings are increasingly exposed to ocean inundation. Read More here
22 August 2016, Washington Post, A widening 80 mile crack is threatening one of Antarctica’s biggest ice shelves. For some time, scientists who focus on Antarctica have been watching the progression of a large crack in one of the world’s great ice shelves — Larsen C, the most northern major ice shelf of the Antarctic peninsula and the fourth largest Antarctic ice shelf overall. Larsen C, according to the British Antarctic Survey, is “slightly smaller than Scotland.” It’s called an ice “shelf” because the entirety of this country-sized area is covered by 350-meter-thick ice that is floating on top of deep ocean waters. The crack in Larsen C grew around 30 kilometers (18.6 miles) in length between 2011 and 2015. And as it grew, also became wider — by 2015, yawning some 200 meters in length. Since then, growth has only continued — and now, a team of researchers monitoring Larsen C say that with the intense winter polar night over Antarctica coming to an end, they’ve been able to catch of glimpse of what happened to the crack during the time when it could not be observed by satellite. The result was astonishing. The rift had grown another 22 kilometers (13.67 miles) since it was last observed in March 2016, and has widened to about 350 meters, report researchers from Project MIDAS, a British Antarctic Survey funded collaboration of researchers from Swansea and Aberystwyth Universities in Wales and other institutions. The full length of the rift is now 130 km, or over 80 miles. Read More here
1 August 2016, Carbon Brief, Guest post: An Antarctic voyage in search of blue carbon. A guest article from Dr David Barnes, a marine benthic ecologist at the British Antarctic Survey, and colleagues Chester Sands, Narissa Bax, Rachel Downey, Christoph Held, Oliver Hogg, Kirill Minin, Camille Moreau, Bernabé Moreno and Maria Lund Paulsen from the Antarctic Seabed Carbon Capture Change project. As global temperatures rise, the response from different parts of the climate system can amplify or dampen the pace of warming. These are known as feedback loops. Melting sea ice, for example, tends to cause a positive feedback loop. The loss of sea ice means that energy from the sun that would have been reflected away by the bright white ice is instead absorbed by the darker ocean. This causes further warming, which in turn causes more sea ice loss, and so on. Negative feedback loops, on the other hand, work to reduce further warming. Blue carbon is one such example. Blue carbon is the term given to carbon stored in coastal or marine ecosystems. It typically refers to salt marshes, mangroves, and seagrass beds, which capture CO2 from the atmosphere and store it in their leaves, stems and in the soil. A less well-known – but no less important – contribution to blue carbon comes from tiny organisms that live on the seabed. These creatures, known as zoobenthos, take up carbon from the plankton they eat and the CO2 in seawater they use to build their skeletons. When the zoobenthos die, their bodies are eventually buried in the sediment of the seabed, sequestering carbon in the process. Our initial research suggests that coastal areas of the Arctic and Antarctic are absorbing and storing more blue carbon as the climate warms. This boost to carbon storage could form one of the biggest negative feedback loops against climate change on Earth. Read More here