18 May 2016, The Conversation, Are toxic algal blooms the new normal for Australia’s major rivers? For much of this year, up to 1,700 kilometres of the Murray River has been hit by a serious outbreak of potentially toxic blue-green algae, which has flourished in the hotter-than-average conditions. After three months, the river is now recovering with the arrival of wet weather. But we are unlikely to have seen the last of these poisonous microbes. Large blue-green algal blooms are a relatively new phenomenon in inland waterways. In 1991 an algal bloom affected more than 1,000 km of the Darling River, the first time such an event had been reported in an Australian river, and one of the few times internationally. It was an environmental disaster, killing livestock and striking a telling blow against Australia’s reputation as a clean, green farming nation. The response was decisive: a state of emergency was declared, and the bloom ultimately gave rise to significant investment by state and federal governments into freshwater research, particularly in the Murray-Darling Basin. Why no emergency now? Fast forward two and a half decades to the latest bloom afflicting the Murray River, one of Australia’s most socially, economically and culturally significant waterways. The past decade has seen four similar blooms on the Murray River: in 2007, 2009, 2010 and now. Yes, they have garnered press attention, but there has not been the same call to arms that we saw when the Darling River was struck in 1991. It is almost as if such significant environmental events are now simply seen as the new normal. Why the apparent complacency? The 2007, 2009 and 2010 algal blooms on the Murray River all happened during the Millennium Drought, and hence were probably ascribed to an aberration in the weather. In reality, the situation may have more to do with how we manage water in Australia – particularly during periods of scarcity, such as the one we may well be entering now. Read More here
Category Archives: Impacts Observed & Projected
11 May 2016, The Conversation, Antarctic ice shows Australia’s drought and flood risk is worse than thought. Australia is systematically underestimating its drought and flood risk because weather records do not capture the full extent of rainfall variability, according to our new research. Our study, published today in the journal Hydrology and Earth System Sciences, uses Antarctic ice core data to reconstruct rainfall for the past 1,000 years for catchments in eastern Australia. The results show that instrumental rainfall records – available for the past 100 years at best, depending on location – do not represent the full range of abnormally wet and dry periods that have occurred over the centuries. In other words, significantly longer and more frequent wet and dry periods were experienced in the pre-instrumental period (that is, before the 20th century) compared with the period over which records have been kept. Reconstructing prehistoric rainfall There is no direct indicator of rainfall patterns for Australia before weather observations began. But, strange as it may sound, there is a link between eastern Australian rainfall and the summer deposition of sea salt in Antarctic ice. This allowed us to deduce rainfall levels by studying ice cores drilled from Law Dome, a small coastal ice cap in East Antarctica. It might sound strange, but there’s a direct link between Antarctic ice and Australia’s rainfall patterns. Tas van Ommen, Author provided How can sea salt deposits in an Antarctic ice core possibly be related to rainfall thousands of kilometres away in Australia? It is because the processes associated with rainfall variability in eastern Australia – such as the El Niño/Southern Oscillation (ENSO), as well as other ocean cycles like the Interdecadal Pacific Oscillation (IPO) and the Southern Annular Mode (SAM) – are also responsible for variations in the wind and circulation patterns that cause sea salt to be deposited in East Antarctica (as outlined in our previous research). By studying an ice record spanning 1,013 years, our results reveal a clear story of wetter wet periods and drier dry periods than is evident in Australia’s much shorter instrumental weather record. Read More here
10 May 2016, New York Times, Global Warming Cited as Wildfires Increase in Fragile Boreal Forest. Scientists say the near-destruction of Fort McMurray last week by a wildfire is the latest indication that the vital boreal forest is at risk from climate change. Scientists have been warning for decades that climate change is a threat to the immense tracts of forest that ring the Northern Hemisphere, with rising temperatures, drying trees and earlier melting of snow contributing to a growing number of wildfires. The near-destruction of a Canadian city last week by a fire that sent almost 90,000 people fleeing for their lives is grim proof that the threat to these vast stands of spruce and other resinous trees, collectively known as the boreal forest, is real. And scientists say a large-scale loss of the forest could have profound consequences for efforts to limit the damage from climate change. In retrospect, it is clear that Fort McMurray, in northern Alberta, was particularly vulnerable as one of the largest human outposts in the boreal forest. But the destruction of patches of this forest by fire, as well as invasions by insects surviving warmer winters, has occurred throughout the hemisphere. In Russia, about 70 million acres burned in 2012, new statistics suggest, much of that in isolated areas of Siberia. Alaska, home to most of the boreal forest in the United States, had its second-largest fire season on record in 2015, with 768 fires burning more than five million acres. Global warming is suspected as a prime culprit in the rise of these fires. The warming is hitting northern regions especially hard: Temperatures are climbing faster there than for the Earth as a whole, snow cover is melting prematurely, and forests are drying out earlier than in the past. The excess heat may even be causing an increase in lightning, which often sets off the most devastating wildfires. Read More here
10 May, The Guardian, Headlines ‘exaggerated’ climate link to sinking of Pacific islands. Links between climate change and the sinking of five islands in the Pacific Ocean have been exaggerated, the author of a widely reported new study has said. The report, published on Friday, tracked the shapeshifting of 33 reef islands in the Solomon Islands between 1947 and 2014. It found that five had been washed away completely and six more had been severely eroded. The study blamed the loss on a combination of sea-level rise and high wave energy. Many media outlets, including the Guardian, jumped to the conclusion that the islands were lost to climate change. But this largely misinterprets the science, according to the study’s author, Dr Simon Albert. “All these headlines are certainly pushing things a bit towards the ‘climate change has made islands vanish’ angle. I would prefer slightly more moderate titles that focus on sea-level rise being the driver rather than simply ‘climate change’,” Albert told the Guardian. The major misunderstanding stems from the conflation of sea-level rise with climate change. As a scientifically robust and potentially destructive articulation of climate change, sea-level rise has become almost synonymous with the warming of the planet. However, as Albert’s paper points out, the ocean has been rising in the Solomon Islands at 7mm per year, more than double the global average. Since the 1990s, trade winds in the Pacific have been particularly intense. This has been driven partly by global warming and partly by climatic cycles – in particular the Pacific Decadal Oscillation. “These trade winds have basically pushed water up into western Pacific and have driven these exceptionally high rates of [sea-level rise] in the Solomons,” said Albert. “The trade winds are partly a natural cycle but also the recent intensification is related to atmospheric warming.” The proportion of the extra rise driven by climate change was not considered by Albert’s study. Read More here