Thirty Years After the Montreal Protocol, Solving the Ozone Problem Remains Elusive

Thirty Years After the Montreal Protocol, Solving the Ozone Problem Remains Elusive

SOURCE: Yale e360 DATE: Aug 14, 2017 SNIP: Did the Montreal Protocol fix the ozone hole? It seemed so. With chlorofluorocarbons (CFCs) and other ozone-eating chemicals banned, many scientists said it was only a matter of time before the ozone layer recharged, and the annual hole over Antarctica healed for good. But 30 years on, some atmospheric chemists are not so sure. The healing is proving painfully slow. And new discoveries about chemicals not covered by the protocol are raising fears that full recovery could be postponed into the 22nd century – or possibly even prevented altogether. …[I]n the past five years, evidence has emerged that potential ozone-eating compounds can reach the ozone layer much faster than previously thought. Under some weather conditions, just a few days may be enough. And that means a wide range of much more short-lived compounds threaten the ozone layer – chemicals not covered by the Montreal Protocol. These compounds are all around us. They are widely used as industrial solvents for tasks like degreasing and dry cleaning. And their releases into the atmosphere are increasing fast. … [Jonathan Shanklin of the British Antarctic Survey] says an important reason for the sluggish recovery of the ozone layer is global warming. As increased levels of greenhouse gases such as carbon dioxide trap more solar heat radiating from the Earth’s surface, less warmth reaches the stratosphere, which cools as a result. This trend has been evident for almost 40 years. A colder stratosphere improves conditions for ozone loss. Climate change “could delay the recovery of the ozone hole well into the second half of this century,”...
Scientists discover 91 volcanoes below Antarctic ice sheet

Scientists discover 91 volcanoes below Antarctic ice sheet

SOURCE: The Guardian DATE: Aug 12, 2017 SNIP: Scientists have uncovered the largest volcanic region on Earth – two kilometres below the surface of the vast ice sheet that covers west Antarctica. The project, by Edinburgh University researchers, has revealed almost 100 volcanoes – with the highest as tall as the Eiger, which stands at almost 4,000 metres in Switzerland. “If one of these volcanoes were to erupt it could further destabilise west Antarctica’s ice sheets,” said glacier expert Robert Bingham, one of the paper’s authors. “Anything that causes the melting of ice – which an eruption certainly would – is likely to speed up the flow of ice into the sea.” The discovery is particularly important because the activity of these volcanoes could have crucial implications for the rest of the planet. If one erupts, it could further destabilise some of the region’s ice sheets, which have already been affected by global warming. Meltwater outflows into the Antarctic ocean could trigger sea level rises. “We just don’t know about how active these volcanoes have been in the past,” Bingham said. However, he pointed to one alarming trend: “The most volcanism that is going in the world at present is in regions that have only recently lost their glacier covering – after the end of the last ice age. These places include Iceland and Alaska.” “Theory suggests that this is occurring because, without ice sheets on top of them, there is a release of pressure on the regions’ volcanoes and they become more...
Geoscientific evidence for subglacial lakes

Geoscientific evidence for subglacial lakes

SOURCE: Alfred Wegener Institute DATE: June 1, 2017 SNIP: During the last glacial period – when the ice in the Antarctic was far thicker and extended further offshore than it does today – it has been speculated that subglacial lakes existed beneath it. An international team of researchers has now successfully sampled the metre-thick sediment layers left behind by these lakes contemporary on the seafloor. Hundreds of subglacial lakes currently exist beneath the Antarctic Ice Sheet, with Lake Vostok being the largest and best known. The challenges involved in exploring these lake systems, which have remained enclosed for thousands of years, are enormous. Satellite-monitoring shows that the movement of water from one lake to another can cause glaciers draining the Antarctic Ice Sheet to move more quickly. “This aspect needs to be taken into account in models designed to make predictions on the future behaviour and dynamics of ice masses, and with them, the degree to which the sea level will rise,” explains AWI marine geologist Kuhn. According to a second study, which Kuhn contributed to and was published in Nature Communications on 17 March 2017, he added: “We have every reason to believe that there are more subglacial lakes in the Antarctic – and more so in the last glacial period – than has been previously assumed. In addition, icecaps like those on the sub-Antarctic island South Georgia and ice sheets reacted much more sensitively and rapidly to climate changes than previously...
Thanks to global warming, Antarctica is beginning to turn green

Thanks to global warming, Antarctica is beginning to turn green

SOURCE: Washington Post DATE: May 18, 2017 SNIP: Researchers in Antarctica have discovered rapidly growing banks of mosses on the ice continent’s northern peninsula, providing striking evidence of climate change in the coldest and most remote parts of the planet. Amid the warming of the last 50 years, the scientists found two different species of mosses undergoing the equivalent of growth spurts, with mosses that once grew less than a millimeter per year now growing over 3 millimeters per year on average. The Antarctic peninsula has been a site of rapid warming, with more days a year where temperatures rise above freezing. The consequence, the study found, was a four- to five-fold increase in the amount of moss growth in the most recent part of the record. Related: Greening in the...

Water Is Streaming Across Antarctica

SOURCE: Columbia University Earth Institute DATE: April 19, 2017 SNIP: In the first such continent-wide survey, scientists have found extensive drainages of meltwater flowing over parts of Antarctica’s ice during the brief summer. Researchers already knew such features existed, but assumed they were confined mainly to Antarctica’s fastest-warming, most northerly reaches. Many of the newly mapped drainages are not new, but the fact they exist at all is significant; they appear to proliferate with small upswings in temperature, so warming projected for this century could quickly magnify their influence on sea level. An accompanying study looks at how such systems might influence the great ice shelves ringing the continent, which some researchers fear could collapse, bringing catastrophic sea-level rises. “This is not in the future—this is widespread now, and has been for decades,” said lead author Jonathan Kingslake, a glaciologist at Columbia University’s Lamont-Doherty Earth Observatory. “I think most polar scientists have considered water moving across the surface of Antarctica to be extremely rare. But we found a lot of it, over very large areas.” Many of the newly mapped drainages start near mountains poking through glaciers, or in areas where powerful winds have scoured snow off underlying bluish ice. These features are darker than the mostly snow-covered ice sheet, and so absorb more solar energy. This causes melting, and on a slope, liquid water then melts a path downhill through overlying snow. If the continent warms this century as projected, this process will occur on a much larger scale, say the authors. “This study tells us there’s already a lot more melting going on than we thought,” said...