17 February 2017, Climate News Network, Canada’s glacial ice loss raises sea level. Dramatic increase in ice loss from the Arctic glaciers of Canada’s northernmost archipelago is now a major contributor to sea level rise. \Glaciers on Canada’s Queen Elizabeth Islands are melting at an ever faster rate. Between 2005 and 2015, ice loss accelerated massively from three billion tonnes a year to 30 billion, according to new research. The islands, which make up Canada’s northernmost archipelago, are home to a quarter of all the Arctic ice − second only to Greenland. And the flow of meltwater there from what once were frozen rivers is now a major contributor to sea level rise. Scientists report in Environmental Research Letters journal that they used satellite data from 1991 to 2015, and ice thickness data from a separate NASAstudy, to calculate ice loss from the Queen Elizabeth Islands. Ice covers 105,000 square kilometres of the archipelago. There are eight ice caps, and altogether 254 glaciers flow into the sea. Glaciers everywhere in the world are in retreat, and researchers warned two years ago that Canada could eventually lose many of its frozen rivers. Read More here
Tag Archives: oceans
10 February 2017, Carbon Brief, Guest post: Why NOAA updates its sea surface temperature record. The National Oceanic and Atmospheric Administration (NOAA) is one of a number of climate agencies that pieces together global temperature from thousands of measurements taken each year across the world’s land and oceans. Last weekend, an article in the Mail on Sunday sparked interest in the way NOAA constructs its temperature record. The claims in the article, widely rebutted shortly after its publication, focused on the most recent version of NOAA’s sea surface temperature (SST) record. I have been involved in the development of this dataset since 2011 and it is due to be updated again shortly. However, an early draft of the journal paper about this update appears to have been circulated amongst media without the permission of the authors (including myself). I have, therefore, decided to make some observations here in a personal capacity that may help make better sense of how the dataset is produced and what it shows. Peer review The status of the new version of our dataset – nominally labelled “ERSSTv5” – is that we have submitted a paper to a journal, and it is undergoing peer review. As is the academic norm, the authors wish to respect the review process and did not give their permission for the draft to be shared with the media. To be clear, the authors have expressly not given permission for the draft to be used or quoted in the media. To be equally clear, at this juncture, copyright of the paper remains with the authors. The peer review process on the paper has only just begun, therefore it is premature and incorrect to analyse the dataset in detail before the paper is published. Peer review is an essential step towards eventual acceptance of any new research. It is highly unusual – and, in my view, undesirable – to discuss the specifics of submitted manuscripts in a public manner before this process has concluded. Peer review will, inevitably, point out ideas which shall serve to strengthen any given analysis. I shall, therefore, not be discussing specific scientific aspects of the draft paper and shall refer to it below only to the barest extent required. If and when the paper is published, this will be the appropriate time to discuss its findings in depth and I would be delighted to do so. Read More here
21 December 2016, Climate News Network, Antarctic rifts launch giant icebergs. Satellite images reveal clue to the hidden cause of fractures in Antarctic shelf ice that are calving huge icebergs into the south polar seas. Scientists in the US have identified an ominous trend in the Southern Ocean − the creation of enormous icebergs as rifts develop in the shelf ice many miles inland. And although three vast icebergs have broken from the Pine Island glacier in West Antarctica and drifted north in this century alone, researchers have only just worked out what has been going on. Their first clue came from a telltale shadow in the south polar ice, caught by a NASA satellite and visible only while the sun was low in the sky, casting a long shadow. It was the first sign of a fracture 20 miles inland, in 2013. Two years later, the rift became complete and the 580 sq km iceberg drifted free of the shelf. Significant collapse “It’s generally accepted that it’s no longer a question of whether the West Antarctic Ice Sheet will melt − it’s a question of when,” says study leader Ian Howat, a glaciologist in the School of Earth Sciences at Ohio State University in the US. “This kind of rifting behaviour provides another mechanism for rapid retreat of these glaciers, adding to the probability that we may see significant collapse of West Antarctica in our lifetimes.” The scientists report in Geophysical Research Letters journal that they had discovered that although shelf ice could be expected to wear at the ocean edge, something else was happening in West Antarctica. The Pine Island glacier is grounded on continental bedrock below sea level, which means that warming ocean water could penetrate far inland beneath the shelf, without anyone being conscious of any change. Read More here
16 December 2016, Australian Antarctic Magazine › 2016-2020 › Issue 31, Low winter sea-ice coverage bucks trend. Winter sea-ice coverage around Antarctica was noticeably reduced in September this year, with sea ice extent starting its annual retreat early and setting new daily record lows. The result comes two years after winter sea ice extent around Antarctica reached a record high in September 2014, when it exceeded 20 million square kilometres for the first time since satellite measurements began in 1979. This year, Antarctic sea ice began its annual spring retreat roughly four weeks earlier than average, after peaking at 18.5 million square kilometres on 28 August 2016, which was close to the lowest winter maximum on record. Dr Jan Lieser from the Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC) and the Australian Research Council-funded Antarctic Gateway Partnership said it was a surprising finding, given the trend in recent years.“Within the space of just two years we have gone from a record high winter sea-ice extent to record daily lows for this point in the season. This is a great reminder that we are dealing with an extremely variable component of the climate system,” Dr Lieser said. “It’s also a reminder of why it can be unwise to leap to conclusions about the link between Antarctic sea ice and climate change on the basis of one or two years of data. It is the long-term trends that are most important, as well as the regional variability, which is high around Antarctica.” Read More here