21 December 2016, Climate Central, The U.S. Has Been Overwhelmingly Hot This Year. In a politically divisive year, there’s been one tie that has bound most of the U.S. together. We all live in the United States of Warming (USW! USW! USW!). In all likelihood, the U.S. is going to have its second-hottest year on record, trailing only 2012. Every state is slated to have a top 10 warmest year and even at the city level, unrelenting warmth has been the main story in 2016. Climate Central conducted an analysis of more than 1,730 weather stations across the Lower 48 that include daily temperature data up until Dec. 15. A paltry 2 percent are having a colder-than-normal year. That leaves 98 percent running above normal. Not only that, 10 percent of those weather stations are having their hottest year on record. Those record-hot places can be found from coast to coast. They include medium-sized cities like Asheville, N.C., Modesto, Calif., and Flint, Mich., as well as lesser-known locales like Neosho, Mo., Callahan, Calif., and Climax, Colo. While some of the heat was driven by the super El Niño earlier this year, that alone doesn’t explain all the records being set, particularly in the latter half of the year after El Niño faded. Climate change has caused the U.S. average temperature to increase about 1.5°F since the 1880s. Read More here and to access graphics
Category Archives: Impacts Observed & Projected
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
19 December 2016, Climate News Network, Growing tornado impact puzzles scientists. The US seems to be experiencing more and worse tornado outbreaks – groups of twisters in quick succession. But climate change may not be the culprit. Tornado outbreaks – those sudden, multiple whirlwinds that can randomly destroy whole townships or pass by and do little more than ruffle the prairie grass – may be getting more frequent and more powerful in the United States. And nobody can be sure why. Climate change driven by global warming which is in turn the consequence of greenhouse gas emissions from fossil fuel combustion could be a candidate cause. But meteorologists cannot rule out some other potential explanation, such as some natural cycle in climate behaviour involving oceans and atmosphere. But they do know that tornado outbreaks are becoming potentially more destructive. Two years ago, researchers checked the data and found that the tornado “season” in the US was now two weeks earlier than it had been in the early 20th century. In the spring of 2016 a team from Columbia University checked the records since 1954 and found that the number of individual tornadoes during any single episode of tornado outbreaks has been rising for the past six decades. Worse winds And now Michael Tippett, a physicist at Columbia Engineering, has returned to the challenge. He and two colleagues report in the journal Science that not only are the numbers of twisters in each outbreak growing, but the overall severity of the whirlwinds is on the increase. And the fastest increase is in the most extreme range of the phenomenon. 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