28 April 2017, Climate News Network, Sea floor erosion causes coral reefs to sink. Five US coral reefs are sinking beneath the waves due to the erosion of the sea floor, robbing coastal communities of their natural storm barrier. The world’s coral reefs are not just in hot water and under threat from acid attack; they may even be getting out of their depth. New research around five US coral reefs shows that even as sea levels rise, the sea floor around the reefs is being eroded. And coral growth simply may not be fast enough to keep up, which means that coastal communities in Florida, the Caribbean and Hawaii could become increasingly at risk from storms, waves and erosion. The news comes close after revelations that great tracts of Australia’s Great Barrier Reef, like other coral colonies, have been devastated by bleaching, as ocean temperatures rise above the levels that corals – animals that live in symbiosis with algae – can tolerate, and researchers have warned that this could soon be happening to reefs almost everywhere, every year. Coral under threat There is already widespread alarm among marine scientists as the seas become measurably more acidic due to an increase in levels of carbon dioxide in the atmosphere, and this too poses a threat to corals everywhere. But while researchers in the tropics had monitored the living reefs of the surface waters, hardly anybody had paid attention to the sea floor around the reefs. Now, scientists of the US Geological Survey report in Biogeosciences that – possibly as a consequence of the degradation of the reefs of the Florida Keys, the US Virgin Islands and the Hawaiian island of Maui – the sea floor is being scoured of sand and sediments, just as sea levels continue to creep to a predicted rise of up to a metre by 2100. Read More here
Tag Archives: Extreme Events
5 April 2017, ECOS, Before the storm. It’s a catastrophe in anyone’s book, not least those of insurance companies anticipating the tens of thousands of claims likely to be lodged.As the floods surged south in the days after Cyclone Debbie hit landfall near Bowen in north Queensland on March 28, a natural disaster was declared in five major centres in northern New South Wales.Citing the chairman of the Insurance Council of Australia, the Australian Financial Review said “in insurance terms, a catastrophe means a disaster that causes a significant number of claims in a region” and for Cyclone Debbie that could be claims over $1 billion. CSIRO’s Dr Chi-Hsiang Wang and colleagues have been researching the cost implications of extreme weather events but with a focus at the other end – predicting the likely cost before the storms. Counting the cost of extreme events Deloitte Access Economics last year delivered a report on building resilient infrastructure which estimated that, between 2002-03 and 2010-11, an annual average of more than $450 million was spent by Australian governments on restoring essential public infrastructure following extreme weather. If it’s business-as-usual, the report said, $17 billion is expected to be spent on direct replacement costs of essential infrastructure due to natural disasters between 2015 and 2050. These estimates don’t factor in the impacts of climate change. In the case of Cyclone Debbie, the wind intensity exceeded the limitations of the building specifications. “It’s not a surprise that we see considerable damage because the intensity is so high,” says Dr Wang. Until now, a cyclone with the force of Debbie was considered a once in a 2,000 year event by Australian design standard for wind actions (AS/NZS 1170.2:2011). That may change. “There’s a consensus among scientists, although not as strong as the consensus around rising global temperatures, that for some tropical cyclone basins around the world they are likely to see events of increased intensity,” he adds. What’s missing? Dr Wang says the current practice for wind impact assessment of physical infrastructure uses only wind intensity (in terms of wind gust) to gauge the damage potential of windstorms. “This ignores other threats brought upon by the accompanying rainfall and storm surge,” he says. Read More here
24 March 2017, Climate News Network, World’s reefs damaged beyond repair. Australia’s Great Barrier Reef and reefs in the Maldives have been dangerously weakened by coral bleaching caused by global warming and El Niño events. The Great Barrier Reef, one of the wonders of the Pacific Ocean, may never fully recover from the combined effects of global warming and an El Niño year, according to a new study in one of the world’s leading science journals. And a second study, in a second journal, warns that increased sea surface temperatures have also caused both a major die-off of corals and the collapse of reef growth rates in the Maldives, in the Indian Ocean. Corals are very sensitive to ocean temperatures, and in unusually hot years – and these have recurred naturally and cyclically since long before humans started burning coal, oil and gas, to accelerate the build-up of greenhouse gases in the atmosphere – the corals react to stress by bleaching. That is, they eject the photosynthesising algae that live with them in symbiosis, to the advantage of both creatures. Hotter oceans But the world’s oceans are becoming hotter anyway, because of global warming driven by greenhouse gas concentrations in the atmosphere. The seas are becoming ever more acidic as atmospheric carbon dioxide reacts with the water. And the periodic return of a blister of oceanic heat in the eastern Pacific called El Niño – Spanish for “The Child”, because it becomes most visible around Christmastime – has begun to put the world’s reefs at risk. The El Niño of 2015-16 triggered a massive episode of bleaching throughout the tropics. And, Australian researchers say in Nature, the bleaching continues. “We’re hoping that the next two to three weeks will cool off quickly, and this year’s bleaching won’t be anything like last year. The severity of the 2016 bleaching was off the chart,” says Terry Hughes, of Australia’s Centre of Excellence for Coral Reef Studies, at James Cook University in Queensland. “It was the third major bleaching to affect the Great Barrier Reef, following earlier heatwaves in 1998 and 2002. Now we’re gearing up to study a potential number four. “We have now assessed whether past exposure to bleaching in 1998 and 2002 made reefs any more tolerant in 2016. Sadly, we found no evidence that past bleaching makes the corals any tougher.” Read More here
24 March 2017, Climate News Network, World’s reefs damaged beyond repair. Australia’s Great Barrier Reef and reefs in the Maldives have been dangerously weakened by coral bleaching caused by global warming and El Niño events. The Great Barrier Reef, one of the wonders of the Pacific Ocean, may never fully recover from the combined effects of global warming and an El Niño year, according to a new study in one of the world’s leading science journals. And a second study, in a second journal, warns that increased sea surface temperatures have also caused both a major die-off of corals and the collapse of reef growth rates in the Maldives, in the Indian Ocean. Corals are very sensitive to ocean temperatures, and in unusually hot years – and these have recurred naturally and cyclically since long before humans started burning coal, oil and gas, to accelerate the build-up of greenhouse gases in the atmosphere – the corals react to stress by bleaching. That is, they eject the photosynthesising algae that live with them in symbiosis, to the advantage of both creatures. Hotter oceans But the world’s oceans are becoming hotter anyway, because of global warming driven by greenhouse gas concentrations in the atmosphere. The seas are becoming ever more acidic as atmospheric carbon dioxide reacts with the water. And the periodic return of a blister of oceanic heat in the eastern Pacific called El Niño – Spanish for “The Child”, because it becomes most visible around Christmastime – has begun to put the world’s reefs at risk. The El Niño of 2015-16 triggered a massive episode of bleaching throughout the tropics. And, Australian researchers say in Nature, the bleaching continues. “We’re hoping that the next two to three weeks will cool off quickly, and this year’s bleaching won’t be anything like last year. The severity of the 2016 bleaching was off the chart,” says Terry Hughes, of Australia’s Centre of Excellence for Coral Reef Studies, at James Cook University in Queensland. “It was the third major bleaching to affect the Great Barrier Reef, following earlier heatwaves in 1998 and 2002. Now we’re gearing up to study a potential number four. Read More here