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
Category Archives: Antarctica
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
20 July 2016, Carbon Brief, In the latter half of the 20th century, the tip of the Antarctic Peninsula was among the fastest warming places on Earth. But since the late 1990s, this fast-paced warming has been tempered by extreme natural forces, according to new research. So much so, that some parts have switched to cooling. In many ways, the results are unsurprising. Scientists know that natural variability superimposes temporary ups and downs on top of greenhouse gas-induced warming everywhere on Earth. Prof Robert Mulvaney, part of the team of British Antarctic Survey scientists who carried out the research, tells Carbon Brief: “The results are as we would expect.” The authors of the study, published today in Nature, also stress their findings are restricted to a small part of the Antarctic Peninsula, and do not imply cooling across the ice sheet as a whole. Read More here
5 July 2016, Washington Post, This new Antarctica study is bad news for climate change doubters. or a number of years now, climate change skeptics have argued that there’s a key part of the Earth’s climate system that upends our expectations about global warming, and that is showing trends that actually cut in the opposite direction. This supposed contrary indicator is the sea ice that rings the Antarctic continent, and that reached a new all-time record extent of 7.78 million square miles in September 2014 (see above). As that record suggests, this vast field of ice has been expanding in recent years, rather than shrinking. That means it’s doing the opposite of what is happening in the Arctic, where sea ice is declining rapidly — and also that it’s doing the opposite of what we might expect in a warming world. [Climate change skeptics may be about to lose one of their favorite arguments] Scientists don’t fully understand why Antarctic sea ice is growing — suggested explanations have posited more glacial melt dumping cold fresh water into the surrounding seas, or the way the Antarctic ozone hole has changed the circulation of winds around the continent. In a new study in Nature Geoscience, though, researchers with the National Center for Atmospheric Research (NCAR) in Boulder, Colo., along with colleagues from the University of Washington in Seattle and Australia, suggest that the phenomenon is simply the result of natural variability of the climate system — driven, in this case, by changes in the tropical Pacific Ocean that reverberate globally. Read more here