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Politics : Formerly About Advanced Micro Devices -- Ignore unavailable to you. Want to Upgrade?

To: Brumar89 who wrote (760179)	12/30/2013 11:35:46 AM
From: TideGlider	4 Recommendations Recommended By average joe Brumar89 FJB longnshort Read Replies (1) \| Respond to of 1575597

To: Brumar89 who wrote (760179)	12/30/2013 11:51:25 AM
From: Wharf Rat	Read Replies (1) \| Respond to of 1575597

Sir David said that levels of carbon dioxide in the atmosphere - the main "green- house gas" causing climate change - were already 50 per cent higher than at any time in the past 420,000 years. The last time they were at this level - 379 parts per million - was 60 million years ago during a rapid period of global warming, he said. Levels soared to 1,000 parts per million, causing a massive reduction of life. "No ice was left on Earth. Antarctica was the best place for mammals to live, and the rest of the world would not sustain human life," he said. Sir David warned that if the world did not curb its burning of fossil fuels "we will reach that level by 2100". web.archive.org The ice cap won't melt that fast. Neither will Greenland. That leaves the high arctic. See Lovelock. Here's some arctic ice stuff. Merry christPIOMAS Santa Claus was worried that his home would soon disappear (it won't, it's safe in Walmart for the time being) and decided to look for information on Arctic sea ice. After all, the best thing you can do when fearing something, is try to understand it. Santa read and thought and read some more for a couple of days, and concluded that one of the best sources of information on the current and near future state of Arctic sea ice was provided by a computer model named PIOMAS that was developed and continuously improved by the good people of the Polar Science Center at the University of Washington. But this was not all. Santa also saw that many amateurs, or citizen scientists, took PIOMAS data and did all kinds of things with it to visualise the sea ice loss or come up with theories to explain and predict sea ice behaviour. Opening PIOMAS' box led Santa to all kinds of goodies and wonderful presents. Take for instance blogger Chris Reynolds. Chris is using PIOMAS gridded data that he breaks down into regions (like the ones Cryosphere Today uses, see image on the right) to get an idea of how sea ice thickness has progressed in all parts of the Arctic, not just as a whole. To quote from one his latest blog posts on Dosbat: So within the Arctic the transition to a seasonally sea ice free state has already occurred in the peripheral seas. This means that the peripheral seas of the Arctic Ocean are now behaving more like the peripheral seas of the PIOMAS domain (first three graphics) than in previous decades. However as this year shows, and possibly as result of the volume pulse of this year, also next year, this seasonally sea ice free state is not yet wholly entrenched. But what of the Central Arctic region? In order for the whole Arctic Ocean to transition to a seasonally sea ice free state the central Arctic must show similar behaviour to the peripheral seas. Besides many interesting regional graphs showing what percentage of different sea ice thickness categories in April has melted out at the end of the melting season, Chris also made this simple graph showing the transition from thick to ever thinner April ice in the Central Arctic, the most important Arctic region when it comes to the question when the Arctic could become ice-free in summer: Why is this important? The more sea ice below a thickness of 2 metres there is in April, the higher the chances of melt-out. But as Chris caveats: From the table of percentage volumes it can be seen that the Central Arctic is in the process of stepping down from the 3 to 4m band to the 2 to 3m band, having already largely stepped out of the 4m and above thickness band. How fast this process will continue is hard to say. Furthermore the Central Arctic is physically protected as the ice edge must recede during the melt season through the peripheral seas of the Arctic, how fast can that process proceed even if the Central Arctic drops into the April thickness region concerned? (...) A final issue to consider is what might drive the acceleration suggested in the plot of all PIOMAS domain percentage open water formation? The most obvious candidate would be ice-albedo feedback. From the persistence of the ice and lack of precipitous crash following 2007 we already know that this feedback is countered by strong negative feedbacks, enhanced autumn/winter ice growth and heat loss being likely the prime movers. However equally, from the volume loss in the Arctic Ocean since then, we know that not all the energy gains, and effect of shortened ice growth season, is being over-ridden by these negative feedbacks. However these issues aside. With the data reported here, I think it foolhardy to dismiss out of hand claims by people like Maslowski and Wadhams that we face a rapid transition to a virtually seasonally sea ice free state across the bulk of the Arctic, including much of the Central Arctic, by the end of this decade. That's the kind of stuff Chris concentrates on using PIOMAS gridded data (read the entire blog post here). But he's not alone. The PIOMAS graph factory known as Wipneus uses the gridded data to produce a map of the Arctic that shows how thick sea ice is all over the Arctic, which is, of course, a very nice addition to the graphs shown in the ASIB monthly PIOMAS updates. Here's the latest map showing November, which Wipneus posted on the Arctic Sea Ice Forum a couple of days ago: And here's an animation of the maps from October and November where last year's thickness is subtracted from this year's thickness (red meaning thicker now, blue meaning thinner now): But is this all, you may wonder. No, this isn't all. There's other folks working on visualisations of the long-term trend - also known as the Arctic Death Spiral - like Andy Lee Robinson with his popular PIOMAS ice cube videos I linked to in the second paragraph and link again to here, and Jim Pettit who has recently been working on these amazing looking 3D graphs: These are just two lame screenshots, check out the impressive 3D stuff here. Jim likes to receive feedback as he's planning to do more of these. And so good old Santa Claus understood more, was less afraid, though not less worried. At the same time he was grateful that scientists were working hard to increase knowledge concerning Arctic sea ice, and that ordinary citizens were working hard to make this knowledge available to their fellow human beings. It produced a feeling of melancholic peacefulness in him. And hope neven1.typepad.com