10 November 2015, The Conversation, Ocean acidification: the forgotten piece of the carbon puzzle. Ocean acidification – the rise in ocean acidity due to the increased absorption of carbon dioxide (CO₂) – is often thought of as consequence of climate change. However, it is actually a separate, albeit very closely-related problem. Ocean acidification is often referred to as “the other CO₂ problem” because, like climate change, it is primarily a result of the increased emissions of this gas. Despite their common driver, though, the processes and impacts of ocean acidification and climate change are distinct. It should not be assumed that policies intended to deal with the climate will simultaneously benefit the oceans. The current emphasis of global climate policies on a warming target is a case in point. A narrow focus on temperature stabilisation, for example, opens the door for policy interventions that prioritise the reduction of greenhouse gases other than carbon dioxide. This is because non-CO₂ greenhouse gases — like methane and nitrous oxide, which can arise from agricultural and industrial processes — typically have a higher global warming potential and might even be less costly than CO₂ to reduce. In addition, several geoengineering schemes have been proposed to reduce the impacts of a warming climate. Yet such schemes often do nothing to address emissions, and may even exacerbate carbon absorption in the oceans. Read More here
Tag Archives: oceans
9 November 2015, Renew Economy, Graph of the Day: Cities under water at 2°C and 4°C. Around half a billion people are at risk from sea level rise if the world continues on a business-as-usual path for carbon emissions, a new report has found – while limiting warming to the recommended 2°C would cut this risk by more than half. The US report by Climate Central, accompanied by an online interactive mapping system, shows that carbon emissions causing 4°C of warming – what business-as-usual points toward today – could lock in enough sea level rise to submerge land currently home to 470 to 760 million people as the “unstoppable rise” unfolds over centuries. The research also reveals, however, that aggressive carbon cuts limiting warming to 2°C could bring the number as low as 130 million people. The report – authored by Climate Central scientists Benjamin Strauss and Scott Kulp, and Anders Levermann of the Potsdam Institute for Climate Impact Research – assesses implications for all coastal nations and cities – post-2100 – using relationships between warming caused by carbon emissions, the long-term global sea level rise it locks in, and global elevation and population data. The news is worst for China, which is found to be most at risk with 145 million people living on land ultimately threatened by rising seas if emission levels are not reduced. Below are the mapped projections for Shanghai, at 4°C on the left, and 2°C on the right. Read More here
5 November 2015, Stockholm Resilience Centre, Seafood trade: A contagious tendency. Global marine resource exploitation can spread in similar patterns to disease epidemics. Current high-speed seafood trade leaves consumers blissfully ignorant of its strains on marine ecosystems and fish species. This is because global trade guarantees consistent availability of fish at affordable prices by sourcing from suppliers around the world, despite fish species being on the brink of extintion. In a new study published in Frontiers in Ecology and the Environment, several Centre colleagues in collaboration with WorldFish argue that global marine resource exploitation can spread in similar patterns to disease epidemics. The study highlights how the speed and connectivity of seafood commerce is severely challenging the capacity of existing regulatory institutions with the potential to decimate fisheries and the livelihoods of those that rely on them. Learn from WHO. Hampus Eriksson, lead author and scientist at World fish says: “Globalized markets connect distant sources of supply with metropolitan areas of demand. Exploitation expands so fast across the world in these modern sourcing networks that overfishing can occur before the resource is even perceived as threatened by management agencies.” The report’s authors propose that international cooperative initiatives, modelled on experiences in managing contagious diseases, could help to ensure the future sustainability of fisheries. Read More here
30 October 2015, Daily Science, Mass gains of Antarctic Ice Sheet greater than losses. A new study says that an increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers. A new NASA study says that an increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers. The research challenges the conclusions of other studies, including the Intergovernmental Panel on Climate Change’s (IPCC) 2013 report, which says that Antarctica is overall losing land ice. According to the new analysis of satellite data, the Antarctic ice sheet showed a net gain of 112 billion tons of ice a year from 1992 to 2001. That net gain slowed to 82 billion tons of ice per year between 2003 and 2008. “We’re essentially in agreement with other studies that show an increase in ice discharge in the Antarctic Peninsula and the Thwaites and Pine Island region of West Antarctica,” said Jay Zwally, a glaciologist with NASA Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study, which was published on Oct. 30 in the Journal of Glaciology. “Our main disagreement is for East Antarctica and the interior of West Antarctica — there, we see an ice gain that exceeds the losses in the other areas.” Zwally added that his team “measured small height changes over large areas, as well as the large changes observed over smaller areas.” Read More here