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
Tag Archives: oceans
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
28 August 2017, Climate Home, Link between Hurricane Harvey and climate change is unclear. Reports the devastating storm was made worse by humanity’s carbon emissions fail to grasp climate change is not just about warming. The unprecedented amount of rainfall accompanying Hurricane Harvey immediately raised the question whether and to what extent climate change is to blame. In a warming world the vapour capacity of the atmosphere increases, and more extreme rainfall, like Texas is witnessing right now, is to be expected as a result. This leads many to conclude that climate change exacerbated the impacts of hurricane Harvey. It is very appropriate to highlight that this is the kind of event we expect to see more of in a warming world. However, to apply this argument directly and attribute (and quantify) the impacts from Harvey itself to human-induced climate change, neglects that climate change is not just about warming. In a changing climate, two effects come together: not only does the atmosphere warm up (thermodynamic effect) but the atmospheric circulation, which determine where, when, and how weather systems develop, can change as well (dynamic effect). Read More here
28 August 2017, Desmog, 12 Years After Katrina, Hurricane Harvey Pummels Gulf Coast and Its Climate Science-Denying Politicians. As the remnants of Hurricane Harvey (now a tropical storm) continue to flood Houston — just days before the 12th anniversary of Hurricane Katrina — I visited Shannon Rainey, whose house was built on top of a Superfund site in the Upper Ninth Ward of New Orleans. Rainey is worried about family members in Houston. She knows all too well how long it can take to get back what is lost in a storm. “I still live with Katrina every day,” she told me. New Orleans remains threatened by bands of rain extending from Harvey, causing many residents with fierce memories of Katrina to remain on edge. Earlier this month, the city proved it was ill-prepared for hurricane season nearly a year after Baton Rouge’s 1,000-year flood. Rain inundated New Orleans, with more than nine inches falling in only three hours, exposing that the city’s pump system could not operate at full capacity. The city is still scrambling to make the needed repairs and clean the sewer system’s catch basins, which remain clogged in many places. Read More here