5 January 2018, Science Journal, Beneath the waves, oxygen disappears. As plastic waste pollutes the oceans and fish stocks decline, unseen below the surface another problem grows: deoxygenation. Breitburg et al. review the evidence for the downward trajectory of oxygen levels in increasing areas of the open ocean and coastal waters. Rising nutrient loads coupled with climate change—each resulting from human activities—are changing ocean biogeochemistry and increasing oxygen consumption. This results in destabilization of sediments and fundamental shifts in the availability of key nutrients. In the short term, some compensatory effects may result in improvements in local fisheries, such as in cases where stocks are squeezed between the surface and elevated oxygen minimum zones. In the longer term, these conditions are unsustainable and may result in ecosystem collapses, which ultimately will cause societal and economic harm. Read More here
Category Archives: Ecosystem Stress
5 January 2018, The Guardian, Oceans suffocating as huge dead zones quadruple since 1950, scientists warn. Ocean dead zones with zero oxygen have quadrupled in size since 1950, scientists have warned, while the number of very low oxygen sites near coasts have multiplied tenfold. Most sea creatures cannot survive in these zones and current trends would lead to mass extinction in the long run, risking dire consequences for the hundreds of millions of people who depend on the sea. Climate change caused by fossil fuel burning is the cause of the large-scale deoxygenation, as warmer waters hold less oxygen. The coastal dead zones result from fertiliser and sewage running off the land and into the seas. The analysis, published in the journal Science, is the first comprehensive analysis of the areas and states: “Major extinction events in Earth’s history have been associated with warm climates and oxygen-deficient oceans.” Denise Breitburg, at the Smithsonian Environmental Research Center in the US and who led the analysis, said: “Under the current trajectory that is where we would be headed. But the consequences to humans of staying on that trajectory are so dire that it is hard to imagine we would go quite that far down that path.” “This is a problem we can solve,” Breitburg said. “Halting climate change requires a global effort, but even local actions can help with nutrient-driven oxygen decline.” She pointed to recoveries in Chesapeake Bay in the US and the Thames river in the UK, where better farm and sewage practices led to dead zones disappearing. However, Prof Robert Diaz at the Virginia Institute of Marine Science, who reviewed the new study, said: “Right now, the increasing expansion of coastal dead zones and decline in open ocean oxygen are not priority problems for governments around the world. Unfortunately, it will take severe and persistent mortality of fisheries for the seriousness of low oxygen to be realised.” Read More here
7 September 2017, The Guardian, The unprecedented drought that’s crippling Montana and North Dakota. hen Rick Kirn planted his 1,000 acres of spring wheat in May, there were no signs of a weather calamity on the horizon. Three months later, when he should have been harvesting and getting ready to sell his wheat, Kirn was staring out across vast cracked, gray, empty fields dotted with weeds and little patches of stunted wheat. “It’s a total loss for me,” said Kirn, who operates a small family wheat farm on the Fort Peck Reservation, an area of north-eastern Montana that lies right in the heart of the extreme climatic episode. “There’s nothing to harvest.” Kirn’s story is typical across the high plains in Montana and the Dakotas this summer, where one of the country’s most important wheat growing regions is in the grips of a crippling drought that came on with hardly any warning and, experts say, is without precedent. While much of the country’s attention in recent weeks has been on the hurricanes striking southern Texas and the Caribbean, a so-called “flash drought”, an unpredictable, sudden event brought on by sustained high temperatures and little rain, has seized a swathe of the country and left farmers with little remedy. Across Montana’s northern border and east into North Dakota, farms are turning out less wheat than last year, much of it poorer quality than normal. Read More here
21 August 2017, The Conversation, Dry winter primes Sydney Basin for early start of bushfire season. It might feel like the depths of winter, but Australian fire services are preparing for an early start to the bushfire season. Sydney has been covered with smoke from hazard reduction burns, and the New South Wales Rural Fire Service has forecast a “horrific” season. Predicting the severity of a bushfire season isn’t easy, and – much like the near-annual announcements of the “worst flu season on record” – repeated warnings can diminish their urgency. However, new modelling that combines Bureau of Meteorology data with NASA satellite imaging has found that record-setting July warmth and low rainfall have created conditions very similar to 2013, when highly destructive bushfires burned across NSW and Victoria. Crucially, this research has found we’re approaching a crucial dryness threshold, past which fires are historically far more dangerous.How to measure bushfire fuel On September 10, 2013 several bushfires in Sydney’s West caused havoc well before the official start of the bushfire season. These were a precursor to fires that destroyed more than 200 properties a month later. Warm, dry winter weather had dried out the fuels in Sydney’s forests and bush reserves beyond “normal” levels for the time of year. The timing and severity of those preseason fires were a reminder that the region’s forests are flammable all year round; they can burn whenever the fuel they contain dries out past a certain threshold. Read More here