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domenica 7 gennaio 2018

Point of No Return


The question for many scientists is whether the carbon cycle is now experiencing a significant jolt that could tip the planet toward a sixth mass extinction




Dead zones in the oceans have quadrupled in size since 1950 - a dramatic surge that has been linked to the animal agriculture industry by scientists.
A new study published in the journal Science found that areas devoid of oxygen in open ocean have soared in the past 50 years, with the number of very low oxygen sites near coasts having multiplied tenfold.
Scientists are warning that this could lead to mass extinction in the long run, as sea creatures cannot survive in these zones - and could also negatively impact the hundreds of millions of people who depend on the sea.
The new study represents the most comprehensive view yet of ocean oxygen depletion, and was published by scientists from GO2NE (Global Ocean Oxygen Network), a United Nations working group which investigates the impact of oxygen loss from the oceans.

Animal agriculture

Climate change and pollution are main drivers for the large-scale deoxygenation of the oceans.
An expert argued that ''unchecked pollution from industrial agriculture' in particular has led to the shocking findings.
Lucia von Reusner, campaign director of campaign group Mighty Earth, which recently exposed a link between the dead zone in the Gulf of Mexico and large scale meat production, said: "These findings are no surprise, and further confirm that the unchecked pollution from industrial agriculture has reached crisis levels and requires immediate action."

Pollution from meat producers

She adds: "These dead zones will continue to expand unless the major meat companies that dominate our global agricultural system start cleaning up their supply chains to keep pollution out of our waters.
"Companies like Tyson Foods are driving the demand for vast quantities of unsustainably-produced corn and soy [animal feed] that are leaking the bulk of the nutrient pollution into our waterways, in addition to the manure that is often dumped on fields where it then washes off into surrounding waterways."

Warning

Denise Breitburg, at the Smithsonian Environmental Research Center in the US and who lead the analysis, explained the grim situation that Earth is facing.
"Oxygen is fundamental to life in the oceans. The decline in ocean oxygen ranks among the most serious effects of human activities on the Earth’s environment.
"Major extinction events in Earth’s history have been associated with warm climates and oxygen-deficient oceans."
Breitburg highlights: "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."

Solution

She goes on to say that it's 'a problem we can solve': "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.
But Prof. Robert Diaz at the Virginia Institute of Marine Science, who reviewed the new study, believes: "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."


WASHINGTON — Global warming is making the world’s oceans sicker, depleting them of oxygen and harming delicate coral reefs more often, two studies show.
The lower oxygen levels are making marine life far more vulnerable, the researchers said. Oxygen is crucial for nearly all life in the oceans, except for a few microbes.
If you can’t breathe, nothing else matters. That pretty much describes it,” said study lead author Denise Breitburg, a marine ecologist at the Smithsonian Environmental Research Center. “As seas are losing oxygen, those areas are no longer habitable by many organisms.”
She was on a team of scientists, convened by the United Nations, who reported that the drop in oxygen levels is getting worse, choking large areas, and is more of a complex problem than previously thought. A second study finds that severe bleaching caused by warmer waters is hitting once-colorful coral reefs four times more often than they used to a few decades ago. Both studies are in Thursday’s edition of the journal Science.
When put all together, there are more than 12 million square miles of ocean with low oxygen levels at a depth of several hundred feet, according to the scientists with the Global Ocean Oxygen Network. That amounts to an area bigger than the continents of Africa or North America, an increase of about 16 percent since 1950. Their report is the most comprehensive look at oxygen deprivation in the world’s seas.
“The low oxygen problem is the biggest unknown climate change consequence out there,” said Lisa Levin, a study co-author and professor of biological oceanography at the Scripps Institution of Oceanography.
Levin said researchers have seen coastal “dead zones” from fertilizer pollution from farms before, as well as areas of low oxygen in open ocean blamed on warmer waters, but this study shows how the two problems are interconnected with common causes and potential solutions.
“Just off Southern California, we’ve lost 20 to 30 percent of our oxygen off the outer shelf,” Levin said. “That’s a huge loss.”
Some low oxygen levels in the world’s ocean are natural, but not this much, Breitburg said. A combination of changes in winds and currents — likely from climate change — is leaving oxygen on the surface, and not bringing it down lower as usual. On top of that, warmer water simply doesn’t hold as much oxygen and less oxygen dissolves and gets into the water, she said.
Oxygen loss is a real and significant problem in the oceans,” said University of Georgia marine scientist Samantha Joye, who wasn’t part of the study but praised it. Levels of ocean oxygen are “changing potentially faster than higher organisms can cope.”
In a separate study, a team of experts looked at 100 coral reefs around the globe and how often they have had severe bleaching since 1980. Bleaching is caused purely by warmer waters, when it’s nearly 2 degrees above the normal highest temperatures for an area.
In the early 1980s, bleaching episodes would happen at a rate of once every 25 to 30 years. As of 2016, they now are happening just under once every six years, the study found.
Bleaching isn’t quite killing the delicate corals, but making them extremely sick by breaking down the crucial microscopic algae living inside the coral. Bleaching is like “ripping out your guts” for coral, said study co-author Mark Eakin, coordinator of the Coral Reef Watch program for the U.S. National Oceanic and Atmospheric Administration.
Guam has been one of the hardest places hit with eight severe bleaching outbreaks since 1994, four of them in the last five years, Eakin said. The Florida Keys, Puerto Rico and Cuba have been hit seven times.
It takes time to recover from bleaching, and the increased frequency means coral doesn’t get the chance to recover before the next outbreak, Eakin said.
Only six of the 100 coral reefs weren’t hit by severe bleaching: four around Australia, one in the Indian Ocean and another off South Africa.
Georgia Tech climate scientist Kim Cobb, who studies reefs but wasn’t part of this international team, applauded the research and said that as the world warms more there will be “profound and lasting damage on global reefs.”

Low oxygen levels, coral bleaching getting worse in oceans  January 6, 2018 Seth Borenstein / Associated Press




The planet's climate is incredibly complex, and scientists are still discovering the effects and consequences of a warming planet – such as a new study finding drastic changes in the chemistry of the ocean waters surrounding the Arctic.
Researchers working near the middle of the Arctic Ocean have found that levels of radium-228 have shot up rapidly over the last decade, as vanishing ice leads to more sediment getting swept up into the water.
Not only does it show how far-reaching and complicated the effects of global warming can be, this could have significant consequences for marine life and the Arctic food chain, according to the researchers, led by a team from the Woods Hole Oceanographic Institution in Massachusetts.
"We suggest that significant changes in the nutrient, carbon, and trace metal balances of the Arctic Ocean are underway, with the potential to affect biological productivity and species assemblages in Arctic surface waters," write the researchers in their paper.
Radium-228 has long been used to work out the flow of land and sediment into the sea – it's a naturally occurring isotope that dissolves into water and so can be tracked by scientists. For this study, multiple ocean readings were taken at 69 sites over the course of a two-month voyage in 2015.
When compared with the previous extensive survey, done in 2007, levels of radium-228 were almost double the recordings from last time.
So what's going on? In an attempt to find out, the team noticed a substantial flow of ice and water moving northwards from Russia along the Transpolar Drift current, ending up in the spot where the increased radium levels had been observed.
That suggests sediments from the East Siberian Arctic Shelf have been making their way from Russia to the centre of the Arctic Ocean.
The scientists think reduced sea ice cover along the Russian coast has led to greater wave activity, as the increased areas of open water get chopped up by the passing winds. That would in turn churn up and release more sediment from the sea bed, including radium and other compounds.
Extra nutrients, carbon, and other chemicals would likely be released through the same mechanism, which would then provide additional food for the plankton at the bottom of the food chain. The whole ecosystem could be altered, say the scientists.
Other factors that could be at play include the way the extra wave activity might pull more sediment into the ocean though coastal erosion, and the possibility of warming temperatures removing permafrost cover and then leading to greater groundwater runoff.
The end result is a whole new mix of chemicals in the sea.
For that reason the scientists are calling for more research into the area from marine geochemists from all nations – after all, it's already been years since the radium levels in this part of the Arctic have been measured, so shorter gaps between readings could help the science greatly.
Until we get a better set of data we won't know for sure how this part of the world is changing, or what might be done to deal with the consequences.
"Continued monitoring of shelf inputs to Arctic surface waters is therefore vital to understand how the changing climate will affect the chemistry, biology, and economic resources of the Arctic Ocean," conclude the researchers.
The research has been published in Science Advances.

In the past 540 million years, the Earth has endured five mass extinction events, each involving processes that upended the normal cycling of carbon through the atmosphere and oceans. These globally fatal perturbations in carbon each unfolded over thousands to millions of years, and are coincident with the widespread extermination of marine species around the world.
The question for many scientists is whether the carbon cycle is now experiencing a significant jolt that could tip the planet toward a sixth mass extinction. In the modern era, carbon dioxide emissions have risen steadily since the 19th century, but deciphering whether this recent spike in carbon could lead to mass extinction has been challenging. That’s mainly because it’s difficult to relate ancient carbon anomalies, occurring over thousands to millions of years, to today’s disruptions, which have taken place over just a little more than a century.
“How can you really compare these great events in the geologic past, which occur over such vast timescales, to what’s going on today, which is centuries at the longest?” says Daniel Rothman professor of geophysics and co-director of MIT’s Lorenz Center,. “So I sat down one summer day and tried to think about how one might go about this systematically.”

This is not saying that disaster occurs the next day,” says Rothman about his new study. “It’s saying that, if left unchecked, the carbon cycle would move into a realm which would be no longer stable, and would behave in a way that would be difficult to predict. In the geologic past, this type of behavior is associated with mass extinction.”

Rothman has analyzed significant changes in the carbon cycle over the last 540 million years, including the five mass extinction events.
He has identified “thresholds of catastrophe” in the carbon cycle that, if exceeded, would lead to an unstable environment, and ultimately, mass extinction.
In a paper published today in Science Advances, he proposes that mass extinction occurs if one of two thresholds are crossed: For changes in the carbon cycle that occur over long timescales, extinctions will follow if those changes occur at rates faster than global ecosystems can adapt. For carbon perturbations that take place over shorter timescales, the pace of carbon-cycle changes will not matter; instead, the size or magnitude of the change will determine the likelihood of an extinction event.
Taking this reasoning forward in time, Rothman predicts that, given the recent rise in carbon dioxide emissions over a relatively short timescale, a sixth extinction will depend on whether a critical amount of carbon is added to the oceans. That amount, he calculates, is about 310 gigatons, which he estimates to be roughly equivalent to the amount of carbon that human activities will have added to the world’s oceans by the year 2100.
Does this mean that mass extinction will soon follow at the turn of the century?
Rothman says it would take some time — about 10,000 years — for such ecological disasters to play out. However, he says that by 2100 the world may have tipped into “unknown territory.”
Rothman had previously done work on the end-Permian extinction, the most severe extinction in Earth’s history, in which a massive pulse of carbon through the Earth’s system was involved in wiping out more than 95 percent of marine species worldwide. Since then, conversations with colleagues spurred him to consider the likelihood of a sixth extinction.


The worst mass extinction in Earth history 26 AGOSTO 2016

He eventually derived a simple mathematical formula based on basic physical principles that relates the critical rate and magnitude of change in the carbon cycle to the timescale that separates fast from slow change. He hypothesized that this formula should predict whether mass extinction, or some other sort of global catastrophe, should occur.
Rothman then asked whether history followed his hypothesis. By searching through hundreds of published geochemistry papers, he identified 31 events in the last 542 million years in which a significant change occurred in Earth’s carbon cycle. For each event, including the five mass extinctions, Rothman noted the change in carbon, expressed in the geochemical record as a change in the relative abundance of two isotopes, carbon-12 and carbon-13. He also noted the duration of time over which the changes occurred.
He then devised a mathematical transformation to convert these quantities into the total mass of carbon that was added to the oceans during each event.
Finally, he plotted both the mass and timescale of each event.


“It became evident that there was a characteristic rate of change that the system basically didn’t like to go past,” Rothman says.

In other words, he observed a common threshold that most of the 31 events appeared to stay under. While these events involved significant changes in carbon, they were relatively benign — not enough to destabilize the system toward catastrophe. In contrast, four of the five mass extinction events lay over the threshold, with the most severe end-Permian extinction being the farthest over the line.
“Then it became a question of figuring out what it meant,” Rothman says.
With further analysis, Rothman found that the critical rate for catastrophe is related to a hidden process within the Earth’s natural carbon cycle. The cycle is essentially a loop between photosynthesis and respiration. Normally, there is a “leak” in the cycle, in which a small amount of organic carbon sinks to the ocean bottom and, over time, is buried as sediment and sequestered from the rest of the carbon cycle.
Rothman found that the critical rate was equivalent to the rate of excess production of carbon dioxide that would result from plugging the leak. Any additional carbon dioxide injected into the cycle could not be described by the loop itself. One or more other processes would instead have taken the carbon cycle into unstable territory.
He then determined that the critical rate applies only beyond the timescale at which the marine carbon cycle can re-establish its equilibrium after it is disturbed. Today, this timescale is about 10,000 years. For much shorter events, the critical threshold is no longer tied to the rate at which carbon is added to the oceans but instead to the carbon’s total mass. Both scenarios would leave an excess of carbon circulating through the oceans and atmosphere, likely resulting in global warming and ocean acidification.
From the critical rate and the equilibrium timescale, Rothman calculated the critical mass of carbon for the modern day to be about 310 gigatons.
He then compared his prediction to the total amount of carbon added to the Earth’s oceans by the year 2100, as projected in the most recent report of the Intergovernmental Panel on Climate Change. The IPCC projections consider four possible pathways for carbon dioxide emissions, ranging from one associated with stringent policies to limit carbon dioxide emissions, to another related to the high range of scenarios with no limitations.
The best-case scenario projects that humans will add 300 gigatons of carbon to the oceans by 2100, while more than 500 gigatons will be added under the worst-case scenario, far exceeding the critical threshold. In all scenarios, Rothman shows that by 2100, the carbon cycle will either be close to or well beyond the threshold for catastrophe.
“There should be ways of pulling back [emissions of carbon dioxide],” Rothman says. “But this work points out reasons why we need to be careful, and it gives more reasons for studying the past to inform the present.”
This research was supported, in part, by NASA and the National Science Foundation.
The Daily Galaxy via MIT News
TRUMP COULD DESTROY THE ENTIRE HUMAN SPECIES, SAYS YALE PSYCHIATRIST WHO WARNED CONGRESS MEMBERS KATE SHERIDAN ON 1/6/18

A paleontologist is warning about ‘sixth extinction’ 24 MAGGIO 2016


Nasa: Global Warming and Mass Extinction 31 AGOSTO 2016






a black-legged kittiwake rests on a rock ledge in Scotland, UK. Photograph: Alamy
Overfishing and climate change are pushing some of the world’s most iconic seabirds to the brink of extinction, according to a new report.
The study reveals that kittiwakes and gannets are among a number of seabirds that have now joined the red list of under-threat birds drawn up by the International Union for Conservation of Nature (IUCN).
Dr Ian Burfield, global science coordinator at Birdlife International which carried out the study for IUCN, said the threat to these birds pointed to a wider environmental challenge.
“Birds are well studied and great indicators of the health of the wider environment. A species at higher risk of extinction is a worrying alarm call that action needs to be taken now.
The study found that overfishing and changes in the Pacific and north Atlantic caused by climate change have affected the availability of sand eels which black-legged kittiwakes feed on during the breeding season.
This has caused “disastrous chick survival rates”, it says, with nesting kittiwake numbers plummeting by 87% since 2000 on the Orkney and Shetland Islands, and by 96% on the Hebridean island of St Kilda.
Globally, the species is thought to have declined by about 40% since the 1970s, justifying its move from the “least concern” category to “vulnerable” on the Red List.
The alarming decline of the black-legged kittiwake and other North Atlantic and Arctic seabirds, such as the Atlantic puffin, provides a painful lesson in what happens when nations take an ‘out of sight, out of mind’ approach to conservation,” said Marguerite Tarzia, European marine conservation officer for BirdLife International.
The study also found that the number of Cape gannets – which breed around Namibia and South Africa – has dropped 50% since the 1950s as food stocks dwindle from overfishing and climate change.
The study also found that the yellow-breasted bunting, once super-abundant, has declined by 80% since 2002, putting it in the highest category, “critically endangered”. It blames illegal trapping in China.
In the North American Arctic, the report found the snowy owl population is much smaller than previously thought and in rapid decline. It said climate change, which has caused snow to melt and reduce rodent cover, was one the key factors.
However, the study did find some positive trends. The Dalmatian pelican has seen its numbers increase in Europe thanks to the introduction of artificial nesting rafts and disturbance prevention. In New Zealand two species of kiwi are more numerous to the control of predators and a programme of egg rearing.
Burfield said: “Thankfully success in kiwi and pelican conservation shows that, when well resourced and supported, conservation efforts really do pay off.”

'Worrying alarm call' for world's birds on brink of extinction Helen Briggs BBC News 12 December 2017


Officials with the US federal government say it is time to consider the possibility that endangered right whales could become extinct unless new steps are taken to protect them.
North Atlantic right whales are among the rarest marine mammals in the world, and they have endured a deadly year. The National Oceanic and Atmospheric Administration has said there are only about 450 of the whales left and 17 of them have died so far in 2017.
The situation is so dire that American and Canadian regulators need to consider the possibility that the population won’t recover without action soon, said John Bullard, the Northeast Regional Administrator for NOAA Fisheries. The high year of mortality is coinciding with a year of poor reproduction, and there are only about 100 breeding female North Atlantic right whales left.
“You do have to use the extinction word, because that’s where the trend lines say they are,” Bullard said. “That’s something we can’t let happen.
Bullard and other NOAA officials made the comments during a meeting of the regulatory New England Fishery Management Council. Mark Murray-Brown, an Endangered Species Act consultant for NOAA, said right whales have been declining in abundance since 2010, with females hit harder than males.
The U.S. and Canada must work to reduce the human-caused deaths of the whales, Murray-Brown said. Vessel-strikes and entanglement in fishing gear are two frequently cited causes of the whales’ deaths.
“The current status of the right whales is a critical situation, and using our available resources to recover right whales is of high importance and high urgency,” he said.
The animals give birth in temperate southern waters and then head to New England and Canada every spring and summer to feed. All of this year’s deaths were off of New England and Canada.
Some recent scientific studies have shed some light on why whale deaths have ticked up. One, published in the journal Nature Scientific Reports, stated that the whales move around much more than previously thought. Some scientists have posited that whales might be venturing outside of protected areas in search of food, putting themselves in harm’s way.
In another study, published last month in the journal Endangered Species Research, scientists examined right whale faeces and found whales that suffer long entanglements in fishing gear produce hormone levels that indicate high stress. The stress negatively impacts their ability to reproduce even when they survive entanglement, scientists said.
“My colleagues are trying to find solutions so we can find out how they can continue to fish, but not entangle whales,” said a study co-author, Elizabeth Burgess, an associate scientist with the Anderson Cabot Center for Ocean Life at the New England Aquarium in Boston.
A five-year NOAA review of right whales that was released in October said the animals should remain on the endangered list. It also included recommendations to protect the species. They included developing a long-term plan for monitoring the population trends and habitat use, and studying the impact of commercial fishing on right whales.
The pockmarks found on the Guiana dolphins’ skin are so horrific that marine wildlife experts fear they have been stricken by a deadly virus or bacteria.

While the coastal waters of the Bay of Sepetiba are reported to be heavily polluted, researchers say there is no sign the animals having been contaminated by chemicals.

Although conservationists do not have an accurate global count of how many Guiana dolphins can still be found on their historic range along the coast of South America, up to 10 per cent of the localised Bay of Sepetiba population are feared to have been wiped out over recent days.

The bay is about 40 miles west of Rio de Janeiro’s famous Copacabana and Ipanema Beaches.

Brazilian conservation organisation Instituto Boto Cinza is monitoring the deaths, currently being recorded at a rate of five a day, and is awaiting scientific results from tissue samples to determine why so many are dying. 
Leonardo Flach, a biologist and the chief coordinator of the non-governmental institute in Mangaratiba, Brazil, believes the cause may bacteria or virus.
He told international media: “We've never experienced this before. 
It’s a tragedy
Every day we are finding four or five dolphin carcasses.
“One day we will find dolphin corpses that are male and adults, and the next day, female and ‘puppies’.  
"Most of them are skinny and with deep skin lesions. 
I’ve never seen anything like that.
The conservationist described the threats faced by the dolphins which can grow to more than six feet and weigh 130lb, saying they face the twin perils of pollution and persecution.
He explained: “The bay of Rio is extremely polluted and unfortunately you have illegal dolphin hunting. 
"They are an endangered species, but with now this unknown disease, we hope to be able to put more pressure on the officials to help us to save the dolphins.
“Otherwise it will be very quick.”
Experts are joining forces to obtain tissue samples from the skin, blood and bones of recovered dolphin carcasses, with a hopes of having a definitive analysis by the end of the month.
If the cause is bacterial, there would an urgent need to create a marine refuge to ensure the dolphins’ survival.
Whale and Dolphin Conservation’s science and policy manager Nicola Hodgins described the dramatic decline of the marine mammals. 
She said: “This is particularly sad news in view of the precarious state of the population. 
“Two decades ago there were around 2,500 of these dolphins, now we are down to just 800 individuals.
“Despite this being a very industrial bay, researchers have found no contamination of the water to-date. 
“Cause of death will have to be confirmed but it is possibly as a result of a disease caused by a virus or bacteria given the appearance of pox-like marks on the skin of the dolphins.” 


Death of 82 stranded dolphins in Florida 18 GENNAIO 2017



VAQUITA: THE BUSINESS OF EXTINCTION 9 DICEMBRE 2017



Humanity driving 'unprecedented' marine extinction 15 SETTEMBRE 2016



High use of pesticides in farms, especially vegetables that are the grazing area for bees, has significantly affected beekeeping businesses in the district.
As bees have started dying on their way back to the hives after grazing, the beekeepers have blamed excessive use of pesticides for the casualty. 
Beekeeping in Dhairing village of Jaljala Rural Municipality is on the verge of extinction due to use of pesticides in the farms, the beekeepers have claimed. 
Dhairing is traditionally a pocket area for beekeeping. In recent times, the business was becoming more commercialized. 
“We had been turning our traditional methods of beekeeping into modern commercial ventures, but number of bees has been declining now,” said Indra Prasad Acharya, a local. “Overuse of pesticides in the feeding zone of bees has created an adverse situation for the survival of bees. The number of bees has been decreasing for the past five years.”
Acharya added that houses that kept bee as a tradition in the past also do not have bees now. Locals of Dhairing have cultivated most of their vegetables for commercial purpose in recent times. Overuse of pesticides to increase the yield of vegetables has directly impacted the beekeeping business. 
According to the locals, the village itself produced good quantity of honey in the past, but now honey is being imported from other places. 
“Dhairing used to be the place where people made good income just from traditional beekeeping, but the situation has changed now,” said Acharya. “The vegetable farmers have aided a lot to the income of the locals, but it has come along with the hazard of pesticides.
“We should have an alternative to the pesticides. Otherwise other sorts of problem than just the death of bees can arise,” added Acharya.
Salyan of Dhairing is the area with the highest vegetable production in the district. The vegetables produced here are exported to nearby markets of Beni bazaar of Myagdi, Baglung bazaar, Milan Chowk bazaar and Kushma.
“We need to conduct studies about the effects of high use of pesticides in the rural municipality,” said Yam Bahadur Malla, chief of Jaljala Rural Municipality. “Our committee will hold discussions about finding an alternative to pesticides in the vegetable farms of the village.”

Turtle doves 'nearing UK extinction because of farming practices' Victoria Ward 23 NOVEMBER 2017



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