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Behind the big freeze Satellites reveal how the ice world is melting Trends Prof Yash
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Behind the big freeze THE bitterly cold weather sweeping Britain and the rest of Europe has been linked by scientists with the ice-free seas of the Arctic, where global warming is exerting its greatest influence. A dramatic loss of sea ice covering the Barents and Kara Seas above northern Russia could explain why a chill Arctic wind has engulfed much of Europe and killed 221 people over the past fortnight. The death toll from Arctic blast has been particularly severe in the Ukraine, where many of the dead have been people sleeping on the streets. Heating and food tents have been set up to ease their hardship. A growing number of experts believe complex wind patterns are being changed because melting Arctic sea ice has exposed huge swaths of normally frozen ocean to the atmosphere above. In particular, the loss of Arctic sea ice could be influencing the development of high-pressure weather systems over northern Russia, which bring very cold winds from the Arctic and Siberia to Western Europe and the British Isles, the scientists believe. An intense anticyclone over north-west Russia is behind the bitterly cold easterly winds that have swept across Europe and some climate scientists say the lack of Arctic sea ice brought about by global warming is responsible. “The current weather pattern fits earlier predictions of computer models for how the atmosphere responds to the loss of sea ice due to global warming,” said Professor Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research. “The ice-free areas of the ocean act like a heater as the water is warmer than the Arctic air above it. This favours the formation of a high-pressure system near the Barents Sea, which steers cold air into Europe.” Sea ice covering the Barents and Kara Seas has been exceptionally low this winter, according to the US National Snow and Ice Data Centre in Boulder, Colorado. But air temperatures above the Barents and Kara Seas have been higher than average. The relatively mild westerly winds that have kept Britain from freezing much of this winter have been blocked by fierce high pressure over north-west Russia, centred on an area just south of the Barents Sea. Studies by scientists at the Alfred Wegener Institute for Polar and Marine Research have confirmed a link between the loss of Arctic sea ice and the development of high-pressure zones in the polar region, which influence wind patterns at lower latitudes further south. Scientists found that as the cap of sea ice is removed from the ocean, huge amounts of heat are released from the sea into the colder air above, causing the air to rise. Rising air destabilises the atmosphere and alters the difference in air pressure between the Arctic and more southerly regions, changing wind patterns. Professor Rahmstorf said the Alfred Wegener study confirms earlier predictions from computer models by Vladimir Petoukhov of the Potsdam Institute, who forecast colder winters in western Europe as a result of melting sea ice. Dr Petoukhov and his colleague Vladimir Semenov were among the first scientists to suggest a link between the loss of sea ice and colder winters in Europe. Their 2009 study simulated the effects of disappearing sea ice and found that for some years to come the loss will increase the chances of colder winters. “Whoever thinks that the shrinking of some far-away sea ice won’t bother him could be wrong. There are complex interconnections in the climate system, and in the Barents-Kara Sea we might have discovered a powerful feedback mechanism,” Dr Petoukhov said. But UK climate researcher Adam Scaife said other complexities are almost certainly influencing the current cold spell. “There is a pretty clear link between the current event and the upper level winds... The winds up at 30 km altitude are very weak,” he said. “We have verified several times using computer model experiments that this leads to high pressure across northern Europe and cold winter conditions in the UK as we see now.” — The Independent
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Satellites reveal how the ice world is melting T HE total volume of water that has melted from all of the world’s polar ice sheets, ice caps and mountain glaciers over the past decade would repeatedly fill Britain’s largest lake, Windemere, more than 13,000 times, according to one of the most comprehensive studies of the Earth’s frozen “cryosphere”. Using a unique pair of satellites that have monitored the disappearing ice over the entire surface of the globe, scientists estimated that some 1,000 cubic miles of ice has disappeared between 2003 and 2010 — enough to cover the US in one-and-a-half feet of water. The survey found that the melting of the cryosphere has been responsible for raising sea levels by about half an inch over the same period, equivalent to a rise of about 1.5mm a year. This was on top of sea-level increases due to the thermal expansion of seawater caused by rising ocean temperatures. Data gathered by the Gravity Recovery and Climate Experiment (GRACE), a joint satellite project run by Nasa and the German government, also found that the amount of ice melting from the mountain glaciers and ice caps that were not in Greenland or Antarctica was actually significantly smaller than previous estimates had suggested. Instead of contributing nearly 1mm of sea level rise per year as previously suggested, some of the Earth’s glaciers and ice caps, especially in the Himalayas and other mountain ranges in Asia, were melting significantly slower than expected, contributing about 0.4mm of sea level rise per year — less than half the amount predicted. One explanation for the previous overestimates could be that most of the glaciers that have been studied intensively are at lower altitudes and therefore more prone to melting. Higher glaciers are colder and less susceptible and yet only 120 glaciers out of 1,60,000 glaciers and ice caps have been directly measured from the ground. The GRACE satellite experiment, however, covered the entire globe and found that all the world’s glaciers and ice caps combined, apart for those in Greenland and Antarctica, had lost about 148 billion tonnes of ice, or about 39 cubic miles, annually between 2003 and 2010. The individual glaciers on the fringes of Greenland and Antarctic contributed an additional 80 billion tons over the same period, the study published in Nature found. “This is the first time anyone has looked at all of the mass loss from all of the Earth’s glaciers and ice caps with GRACE,” said John Wahr, professor of physics at the University of Colorado at Boulder, who was part of the research team that analysed the satellite data. “The Earth is losing an incredible amount of ice to the oceans annually, and these new results will help us to answer important questions in terms of both sea-level rise and how the planet’s cold regions are responding to global change.” Professor Jonathan Bamber, of Bristol University, said: “Melting glaciers are an iconic symbol of climate change... they seem to have been receding, largely uninterrupted, almost everywhere around the world for several decades.”
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Trends CAPE CANAVERAL, Florida: NASA is looking for at least two US firms to design and build space taxis to ferry astronauts to and from the International Space Station, program managers said. NASA plans to invest $300 million to $500 million in each of the firms selected under new 21-month partnership agreements, Ed Mango, manager of NASA's Commercial Crew program, said at an industry briefing at the Kennedy Space Center. Neuroscience the new front of warfare LONDON: Directed energy weapons that use wave beams to cause pain, and electrical brain stimulation that boosts a soldier's combat ability — it may sound like science fiction warfare, but experts say advances in neuroscience mean it's on the horizon. Rapid progress in the ability to map brain activity and manipulate its responses with stimulants could change the face of warfare, a panel of experts said. — Reuters
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THIS UNIVERSE All I can say is that I do not see how to introduce physical considerations that would demand something moving faster than light. You must have heard of some murmurs in this direction because of some experiments with neutrinos. Those observations do not make sense to me. I think there is likely to be another explanation. The world was shocked over a hundred years ago when Einstein came with the requirement that there should be an upper limit to velocity of things. But then it led to the beautiful theory of relativity and the momentous suggestion that matter is just a condensed form of energy. This was not a mere suggestion but some thing that took us far towards understanding the world of things from the tiniest to the largest like stars and galaxies. I am not saying that other revolutions are not allowed. But I do not see a tangible way of introducing a new velocity regime. Some years ago, it was suggested by George Sudershan that we might have particles of imaginary mass and a minimum velocity equal to that of light! It is possible that the universe might still run if that came to be right! I will not bet on it.
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THE bitterly cold weather sweeping Britain and the rest of Europe has been linked by scientists with the ice-free seas of the Arctic, where global warming is exerting its greatest influence. A dramatic loss of sea ice covering the Barents and Kara Seas above northern Russia could explain why a chill Arctic wind has engulfed much of Europe and killed 221 people over the past fortnight.
