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
Yearly Archives: 2018
4 January 2018, Geophysical Research Letters, Decline in Antarctic Ozone Depletion and Lower Stratospheric Chlorine Determined From Aura Microwave Limb Sounder Observations. The Antarctic ozone hole is healing slowly because levels of the man-made chemicals causing the hole have long lifetimes. We use Microwave Limb Sounder (MLS) satellite data to measure O3 over Antarctica at the beginning of winter and then compare it to O3 near the end of winter to calculate depletion. During this period, nearly all O3 change is due to depletion. MLS also measures HCl, and when ozone levels are very low, nearly all the reactive chlorine species (Cly) are converted to HCl. Clyvaries a lot from year to year from atmospheric motions. Fortunately, MLS measures nitrous oxide (N2O), a long-lived gas that also varies with the motions. Using the ratio of Cly to N2O, we find that there is less chlorine now than 9 years ago and that Cly has decreased on average about 25 parts per trillion/yr (0.8%/yr). The O3 depletion we calculate from MLS data responds to changes in the Clylevels, and the ratio of the change in ozone loss to the change in Cly matches model calculations. All of this is evidence that the Montreal Protocol is working—the Cly is decreasing in the Antarctic stratosphere and the ozone destruction is decreasing along with it. Read More here
4 January 2018: The first complete temperature datasets for 2017 show that last year was the third in a row of exceptionally warm years, the Copernicus Climate Change Service (C3S) implemented by the European Weather Centre (ECMWF) can announce. One data set, produced by ECMWF, shows that the global average surface air temperature exceeded 14.7°C, making 2017:
- about 0.1°C cooler than the warmest year on record, 2016, and warmer than the previous second warmest year, 2015
- the warmest year on record not influenced by warming El Niño conditions in the tropical Pacific
- around 0.5°C warmer than the 1981–2010 climatological reference period
- an estimated 1.2°C warmer than the pre-industrial value for the 18th century.
Comparable results have been obtained by C3S from a reanalysis dataset produced by the Japan Meteorological Agency (JMA). The method used to produce the datasets is to combine millions of meteorological and marine observations, including from satellites, with models to produce a complete reanalysis of the atmosphere. The combination of observations with models makes it possible to estimate temperatures at any time and in any place across the globe, even in data-sparse areas such as the polar regions. The results support the provisional announcement by the World Meteorological Organization (WMO) two months ago that 2017 was set to be among the three warmest years on record. Other datasets used in the WMO announcement, which are derived from monthly climatological data for a smaller number of long-term observing sites, are also expected to concur when they are released shortly. All datasets will contribute to the consolidated statement to be issued by WMO on 2017 temperatures. Read More here
1 January 2018, Independent, Arctic warming linked to wet summers and snowy winters in the UK, scientists warn. Record wet summers and severe snowy weather in winter seen in recent years in the UK could be linked to Arctic warming, scientists have said. The UK has been hit by a number of extreme weather events in the past decade, including heavy rain in summer 2007 and 2012, the record wet and stormy winter of 2013/14 and cold and snowy winters in 2009/10 and 2010/11. Researchers compared data of recent UK extremes with the position of the North Atlantic polar atmospheric “jet stream” – a giant current of air – using a measure called the North Atlantic Oscillation (NAO) index which indicates shifts north and south. The exceptional wet summers, snowy cold snaps and mild stormy winters all corresponded with pronounced negative or positive spikes in readings of the index, showing more extreme north and southward movements of the jet stream. The researchers also linked the jet stream’s altered path – its increasing “waviness” – with a rise in summer months of areas of high pressure remaining largely stationary over Greenland, distorting the path of storms across the North Atlantic. Read More here