Category Archives: Impacts Observed & Projected

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26 October 2015, Washington Post, Scientists confirm that East Antarctica’s biggest glacier is melting from below. Earlier this year, we learned some worrisome climate news. Although Antarctic scientists have been most concerned about loss of ice in the western part of Antarctica, a study in Nature Geoscience suggested a vulnerability in the much larger ice sheet of East Antarctica, as well. East Antarctica’s enormous Totten Glacier, you see, has a key similarity with the glaciers of West Antarctica — namely, it is rooted deep below sea level. This means that it is potentially exposed to warm ocean waters, and the study in March uncovered a deep and 5-kilometer wide subsea valley beneath the glacier’s oceanfront ice shelf that, the authors said, could be a route for warm offshore water to reach its base. This might explain why the glacier has been observed to be thinning and lowering, or losing elevation, over time, they noted. Located along East Antarctica’s Sabrina Coast, Totten glacier is the ice sheet’s largest. It holds back 3.9 meters of potential sea level rise, or over 12 feet, and connects with the very deep and vast Aurora Subglacial Basin, which is also rooted well below sea level. So the results were treated as being of enormous consequence. But they’re not the end of the story, as there is vastly more to learn about Totten glacier. A new study out in Geophysical Research Letters reaffirms some of these core concerns about Totten’s melt — while also appearing to partly alleviate others. Read More here

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22 October 2015, Carbon Brief, Five charts that show how Arctic and Antarctic sea ice is faring in 2015. At this time of year, there are big differences in what’s going on with sea ice at either end of the world. September saw the Arctic hit its fourth lowest summer minimum on record, while over in Antarctica, the winter maximum finished just above average, ending a streak of record highs in the last three years. Carbon Brief takes a look at what’s happened this year and how it fits in with long term trends. Summer minimum Scientists have been using satellites to measure sea ice extent at the north and south poles since the late 1970s. They take measurements daily, and record the annual minimum and maximum as an indicator of how the poles are changing. In the Arctic, the end of the summer marks the point when sea ice is at its smallest extent, before it freezes up again as temperatures fall. Scientists keep a close eye around the time the low is normally reached – usually mid september – then look for signs of ice accumulating again in order to pinpoint exactly when the summer minimum is reached. According to the National Snow and Ice Data Center (NSIDC) in the US, the summer low occurred this year on 11 September. But because sea ice can throw in a late dip or surge, the NSIDC waited until 6 October before finally confirming this summer’s minimum of 4.41m square kilometers (sq km) – the fourth lowest on record. So how did the rest of the season shape up before this point? Read More here

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22 October 2015, Science Daily, Measuring the impacts of severe wildfires in the Arctic. Based on the number of acres burned, 2015 is shaping up to be the second most extreme fire year during the past decade in North America’s boreal region. Historically, the area has had one or fewer extreme fire years per decade. This season, 15 million acres burned in Alaska and Canada, according Northern Arizona University’s Michelle Mack, researcher and biological sciences professor, who is leading a NASA-funded project to measure the severe fire impacts in North America. “In the boreal region, there is a thick organic layer on the surface comprised of litter and soil, that in some cases is hundreds to thousands of years old,” Mack said. “Will more fires and hotter fires burn that layer and release it to the atmosphere and how deep will it burn into the soil?” These questions are part of NASA’s $100 million dollar, 10 year project called Arctic Boreal Vulnerability Experiment, also known as ABoVE. The experiment seeks to understand the vulnerability and resilience in the Arctic, where climate change is most pronounced and rapidly unfolding. Mack serves on the project’s international science team tasked with implementing the field campaign. Read More here

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22 October 2015, The Guardian. Perth’s double whammy: as sea levels rise the city itself is sinking. The city’s growing population means a growing demand for water, but as more and more water is drawn out of Perth’s acquifers, the land is slowly subsiding. Growing demand for water in Perth has caused the city to sink at up to 6mm a year and could be responsible for an apparent acceleration in the rate of sea level rise, according to new research released by Curtin University. The study, published in the Journal of Geophysical Research in October, found that the rate of subsidence in Perth increased between 2000 and 2005, at the same time as the Water Corporation of WA increased the amount of water it was drawing from the city’s two main aquifers to meet the demands of a growing population. Will Featherstone, professor of geodesy at Curtin and the lead author of the study, described the effect as “like slowly letting the air out of a balloon”. “If you take the water out of the ground, the overburden of all the rocks above pushes down,” he told Guardian Australia. The city appears to be sinking at a rate of between 2mm and 6mm a year, variable throughout the Perth basin. The greatest change was measured at the seaside suburb of Hillarys, which has a GPS sensor to measure the rate of subsidence and a tidal marker operating side by side. Data for much of the Perth basin is patchy. A sinking city also has ramifications for the measurement of sea levels. A few years ago the rate of sea level rise in Western Australia was reported – not entirely accurately, it turned out – to be three times greater than the global average. Read More here