7 June 2016, Washington Post, ‘We’ve never seen anything like this’: Arctic sea ice hit a stunning new low in May. The 2016 race downward in Arctic sea ice continued in May with a dramatic new record. The average area of sea ice atop the Arctic Ocean last month was just 12 million square kilometers (4.63 million square miles), according to the National Snow and Ice Data Center (NSIDC). That beats the prior May record (from 2004) by more than half a million square kilometers, and is well over a million square kilometers, or 500,000 square miles, below the average for the month. Another way to put it is this: The Arctic Ocean this May had more than three Californias less sea ice cover than it did during an average May between 1981 and 2010. And it broke the prior record low for May by a region larger than California, although not quite as large as Texas. This matters because 2016 could be marching toward a new record for the lowest amount of ice ever observed on top of the world at the height of melt season — September. The previous record September low was set in 2012. But here’s what the National Snow and Ice Data Center has to say about that: Daily extents in May were also two to four weeks ahead of levels seen in 2012, which had the lowest September extent in the satellite record. The monthly average extent for May 2016 is more than one million square kilometers (386,000 square miles) below that observed in May 2012.In other words, for Arctic sea ice, May 2016 was more like June 2012 — the record-breaking year. Going into the truly warm months of the year, then, the ice is in a uniquely weak state. “We’ve never seen anything like this before,” said Mark Serreze, who directs the center. “It’s way below the previous record, very far below it, and we’re something like almost a month ahead of where we were in 2012.” Granted, the NSIDC called the May numbers “tentative” because of problems with the satellites that scientists rely on to observe the Arctic, but added that they are “supported by other data sources.” Read More here
Tag Archives: oceans
27 May 2016, The Conversation, Antarctica may not be as isolated as we thought, and that’s a worry. For a long time, we have thought of Antarctica as isolated from the rest of the world. The continent is entirely surrounded by the Southern Ocean, which heaves with giant waves whipped up by intense winds, and is home to the world’s strongest ocean current, the eastward-flowing Antarctic circumpolar current (ACC). The Southern Ocean is associated with several circumpolar oceanic fronts (see image below), where sharp transitions in ocean temperature and salinity occur. One of the most significant of these is the Antarctic polar front, a convergence zone where cold Antarctic water sinks under warmer sub-Antarctic water. Ocean barrier The polar front was considered as a barrier blocking movement of marine plants and animals into and out of Antarctica. Many groups of organisms show strong differences on either side of the front, suggesting northern and southern populations have been separated for a long time. We know from genetic work that some species, such as some molluscs and crustaceans, have managed to cross the front in the past, but there is little evidence that biological movement across the front can or does still occur. Read More here
23 May 2016, The Conversation, Coastal law shift from property rights to climate adaptation is a landmark reform. Coastal management in Australia is subject to competing interests and challenges. These range from land use and strategic planning issues to ecosystems preservation. Local councils are at the coalface as both key decision-makers and the first point of contact for communities. Exacerbating these day-to-day challenges for councils are risks to property. A quantitative assessment undertaken by the then-Department of Climate Change in 2009 identified impacts of sea-level rise as a serious threat to property. In New South Wales, under scenarios of a 1.1-metre sea-level rise, risks of damage or inundation to residential housing alone affected tens of thousands of properties, potentially costing millions of dollars. The NSW 2009 sea-level rise policy (now repealed) saw coastal councils considering this future risk when developing coastal zone management plans. These metrics, while important, say little of the wide-ranging benefits of a freely accessible coast. Going to the beach is a fundamental part of Australian identity; it’s a “special place” for Australians. Local councils are most exposed to the issues and challenges of a changing coastline in which there are many interests. Councils are often the first decision-makers for local development, asset management and land-use and strategic planning. Increased coastal erosion, storm events, more frequent and severe flooding impacts and higher tides can and will make these regular functions of councils more complicated. In this context, the tabling of the NSW Coastal Management Bill on May 3 marks the formalisation of Stage 2 of the most significant law reform to coastal management since the 1970s. The NSW state government saysthat, by better integrating coastal management with land-use planning, the legislation offers: … a modern, coherent coastal management framework that is responsive to current needs and future challenges. Read More here
21 May 2016, Climate News Network, Antarctic glacier melt could raise sea level by 3m. A huge glacier in the frozen wastes of East Antarctica, a region previously thought stable, could melt much faster than expected, scientists say. One of Antarctica’s great glaciers could become unstable if global warming continues at the present pace. As warm seas wash the ice shelf, the land-based mass of ice could begin to retreat, cross a critical threshold in the present century and then withdraw 300 kilometres inland. In the course of doing so it would spill tremendous quantities of water into the oceans: enough to raise global sea levels by 2.9 metres and threaten cities that are home to billions. And here is the bad news: glaciologists have known for decades that West Antarctica’s ice sheets are unstable. But the Totten glacier is part of the East Antarctic Ice Sheet, a mass of ice most researchers had believed to be stable and highly unlikely to lose much of its ice, even in a warming world. Scientists from Australia, New Zealand, the US and Britain report in Nature that they explored the underlying geology of the Totten glacier to build up a picture of its advance and retreat over many millions of years. Greater vulnerability “The evidence coming together is painting a picture of East Antarctica being much more vulnerable to a warming environment than we thought,” said Martin Siegert, co-director of the Grantham Institute at Imperial College London. “This is something we should worry about. “Totten Glacier is losing ice now, and the warm ocean water that is causing this loss has the potential to also push the glacier back to an unstable place.” The identification of a weak spot in the bastion of frozen water that embraces East Antarctica is new. But alarm about the rate of melting and the potential for change across the world’s last largely uninhabited continent is not. In the past few years researchers have pinpointed the insidious effect of warming sea currents, and identified immediate hazards to the glaciers of the fast-warming West Antarctic region. Read More here