29 September 2016, The Conversation, Record high to record low: what on earth is happening to Antarctica’s sea ice? 2016 continues to be a momentous year for Australia’s climate, on track to be the new hottest year on record. To our south, Antarctica has also just broken a new climate record, with record low winter sea ice. After a peak of 18.5 million square kilometres in late August, sea ice began retreating about a month ahead of schedule and has been setting daily low records through most of September. It may not seem unusual in a warming world to hear that Antarctica’s sea ice – the ice that forms each winter as the surface layer of the ocean freezes – is reducing. But this year’s record low comes hot on the heels of record high sea ice just two years ago. Overall, Antarctica’s sea ice has been growing, not shrinking. So how should we interpret this apparent backflip? In our paper published today in Nature Climate Change we review the latest science on Antarctica’s climate, and why it seems so confusing. Antarctic surprises. First up, Antarctic climate records are seriously short. The International Geophysical Year in 1957/58 marked the start of many sustained scientific efforts in Antarctica, including regular weather readings at research bases. These bases are mostly found on the more accessible parts of Antarctica’s coast, and so the network – while incredibly valuable – leaves vast areas of the continent and surrounding oceans without any data. In the end, it took the arrival of satellite monitoring in the 1979 to deliver surface climate information covering all of Antarctica and the Southern Ocean. What scientists have observed since has been surprising. Read More here
Category Archives: Impacts Observed & Projected
29 September 2016, Climate News Network, Speed of Arctic changes defies scientists.The Arctic climate is changing so quickly that science can barely keep track of what is happening and predict the global consequences, the UN says. In an unusually stark warning a leading international scientific body says the Arctic climate is changing so fast that researchers are struggling to keep up. The changes happening there, it says, are affecting the weather worldwide. The World Meteorological Organisation (WMO) says: “Dramatic and unprecedented warming in the Arctic is driving sea level rise, affecting weather patterns around the world and may trigger even more changes in the climate system. “The rate of change is challenging the current scientific capacity to monitor and predict what is becoming a journey into uncharted territory.” The WMO is the United Nations’ main agency responsible for weather, climate and water. Its president, David Grimes, said: “The Arctic is a principal, global driver of the climate system and is undergoing an unprecedented rate of change with consequences far beyond its boundaries. Read More here
27 September 2016, Climate Central, The World Passes 400 PPM Threshold. Permanently. In the centuries to come, history books will likely look back on September 2016 as a major milestone for the world’s climate. At a time when atmospheric carbon dioxide is usually at its minimum, the monthly value failed to drop below 400 parts per million. That all but ensures that 2016 will be the year that carbon dioxide officially passed the symbolic 400 ppm mark, never to return below it in our lifetimes, according to scientists. Because carbon pollution has been increasing since the start of the Industrial Revolution and has shown no signs of abating, it was more a question of “when” rather than “if” we would cross this threshold. The inevitability doesn’t make it any less significant, though. September is usually the month when carbon dioxide is at its lowest after a summer of plants growing and sucking it up in the northern hemisphere. As fall wears on, those plants lose their leaves, which in turn decompose, releasing the stored carbon dioxide back into the atmosphere. At Mauna Loa Observatory, the world’s marquee site for monitoring carbon dioxide, there are signs that the process has begun but levels have remained above 400 ppm. Read more here
22 September 2016, The Conversation, The Great Barrier Reef’s ‘new normal’ is a forlorn sight. Images of this year’s coral bleaching on the Great Barrier Reef shocked the world. Some tour operators expressed concern that the extensive and sometimes simplistic media coverage would hurt their businesses. The reef was a hot-button issue during the federal election, with both major parties pledging funding for programs to enhance water quality. Some politicians and tour operators expressed optimism about the reef’s ability to recover. It was the culmination of the longest, most extensive and most severe mass coral bleaching event ever recorded – an event that began in the North Pacific in mid-2014. The Great Barrier Reef was not spared, this year experiencing its hottest sea surface temperatures since records began – 29.1℃ in February (1.1℃ above the 1961-90 average), 29.1℃ (1.3℃ above average) in March and 27.8℃ (1.0℃ above average) in April. Evidence of bleaching was found on 93% of the more than 900 individual reefs surveyed that month, with the most severe impacts on the most pristine and isolated reefs of the far north. A preliminary estimate is that 22% of coral has now died, with 85% of these deaths occurring between Cape York and just north of Lizard Island. Read More here