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How to work out which coral reefs will bleach, and which might be spared

The Conversation - Tue, 2017-10-03 04:40

Regional variations in sea surface temperature, related to seasons and El Niño, could be crucial for the survival of coral reefs, according to our new research. This suggests that we should be able to identify the reefs most at risk of mass bleaching, and those that are more likely to survive unscathed.

Healthy coral reefs support diverse ecosystems, hosting 25% of all marine fish species. They provide food, coastal protection and livelihoods for at least 500 million people.

But global warming, coupled with other pressures such as nutrient and sediment input, changes in sea level, waves, storms, ventilation, hydrodynamics, and ocean acidification, could lead to the end of the world’s coral reefs in a couple of decades.

Read more: How much coral has died in the Great Barrier Reef’s worst bleaching event?

Climate warming is the major cause of stress for corals. The world just witnessed an event described as the “longest global coral die-off on record”, and scientists have been raising the alarm about coral bleaching for decades.

The first global-scale mass bleaching event happened in 1998, destroying 16% of the world coral reefs. Unless greenhouse emissions are drastically reduced, the question is no longer if coral bleaching will happen again, but when and how often?

To help protect coral reefs and their ecosystems, effective management and conservation strategies are crucial. Our research shows that understanding the relationship between natural variations of sea temperature and human-driven ocean warming will help us identify the areas that are most at risk, and also those that are best placed to provide safe haven.

A recurrent threat

Bleaching happens when sea temperatures are unusually high, causing the corals to expel the coloured algae that live within their tissues. Without these algae, corals are unable to reproduce or to build their skeletons properly, and can ultimately die.

The two most devastating global mass bleaching events on record – in 1998 and 2016 – were both triggered by El Niño. But when water temperatures drop back to normal, corals can often recover.

Certain types of coral can also acclimatise to rising sea temperatures. But as our planet warms, periods of bleaching risk will become more frequent and more severe. As a consequence, corals will have less and less time to recover between bleaching events.

We are already witnessing a decline in coral reefs. Global populations have declined by 1-2% per year in response to repeated bleaching events. Closer to home, the Great Barrier Reef lost 50% of its coral cover between 1985 and 2012.

A non-uniform response to warming

While the future of worldwide coral reefs looks dim, not all reefs will be at risk of recurrent bleaching at the same time. In particular, reefs located south of 15ºS (including the Great Barrier Reef, as well as islands in south Polynesia and Melanesia) are likely to be the last regions to be affected by harmful recurrent bleaching.

We used to think that Micronesia’s reefs would be among the first to die off, because the climate is warming faster there than in many other places. But our research, published today in Nature Climate Change, shows that the overall increase in temperature is not the only factor that affects coral bleaching response.

In fact, the key determinant of recurrent bleaching is the natural variability of ocean temperature. Under warming, temperature variations associated with seasons and climate processes like El Niño influence the pace of recurrent bleaching, and explain why some reefs will experience bleaching risk sooner than others in the future.

Different zones of the Pacific are likely to experience differing amounts of climate variability. Author provided Degrees of future bleaching risk for corals in the three main Pacific zones. Author provided

Our results suggest that El Niño events will continue to be the major drivers of mass bleaching events in the central Pacific. As average ocean temperatures rise, even mild El Niño events will have the potential to trigger widespread bleaching, meaning that these regions could face severe bleaching every three to five years within just a few decades. In contrast, only the strongest El Niño events will cause mass bleaching in the South Pacific.

In the future, the risk of recurrent bleaching will be more seasonally driven in the South Pacific. Once the global warming signal pushes summer temperatures to dangerously warm levels, the coral reefs will experience bleaching events every summers. In the western Pacific, the absence of natural variations of temperatures initially protects the coral reefs, but only a small warming increase can rapidly transition the coral reefs from a safe haven to a permanent bleaching situation.

Read more: Feeling helpless about the Great Barrier Reef? Here’s one way you can help

One consequence is that, for future projections of coral bleaching risk, the global warming rate is important but the details of the regional warming are not so much. The absence of consensus about regional patterns of warming across climate models is therefore less of an obstacle than previously thought, because globally averaged warming provided by climate models combined with locally observed sea temperature variations will give us better projections anyway.

Understanding the regional differences can help reef managers identify the reef areas that are at high risk of recurring bleaching events, and which ones are potential temporary safe havens. This can buy us valuable time in the battle to protect the world’s corals.

The Conversation

Clothilde Emilie Langlais was funded by the Pacific Australian Climate Science and Adaptation Program funded by AusAid.

Scott Heron receives funding and support from the U.S. National Oceanic and Atmospheric Administration's Satellites division (NESDIS) and Coral Reef Conservation Program, and is affiliated with James Cook University. The contents in this piece are solely the opinions of the authors and do not constitute a statement of policy, decision or position on behalf of NOAA or the U.S. Government.

Andrew Lenton does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

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Slinging mud: inside (and outside) the UK's biggest fracking site

The Guardian - Tue, 2017-10-03 03:59

As horizontal drilling starts in Lancashire this month, the Guardian talks to protesters and staff at the Cuadrilla well

Mike Hill, sitting in his living room a few miles from a fracking site outside Blackpool, is brandishing a government letter brushing aside his concerns about the industry. “You, Theresa May, overruled democracy to force fracking on the residents of Fylde,” he says, referring to his own letter to the prime minister, in which he urges her to heed experts’ calls for tighter shale gas regulations.

“And then you won’t pay attention, the slightest attention, to anybody in regards fracking regulation, fracking monitoring, public health risks, risks to indigenous industries,” says the chartered engineer, who used to work in the oil and gas sector.

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Michael Gove suggests plastic bottle deposit scheme

BBC - Tue, 2017-10-03 02:54
Michael Gove wants views on whether a "reward and return" system would improve recycling in England.
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Michael Gove calls for views on setting up plastic bottle deposit return scheme

The Guardian - Tue, 2017-10-03 02:02

Environment secretary says working group will look at how a deposit return scheme could help reduce plastic waste in England

A deposit return scheme aimed at slashing plastic pollution has moved significantly closer after environment secretary Michael Gove said he would work with the industry to see how a scheme can be implemented in England.

Gove, speaking at the Conservative party conference in Manchester, announced a four-week call for views to inform how a deposit return scheme (DRS) would be designed. The government’s working group on the issue will also consider DRS for metal and glass containers.

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Wildscreen's Witness the Wild open-air exhibition – in pictures

The Guardian - Tue, 2017-10-03 00:50

Bristol’s open-air arts trail sees large-scale images of ocean life by some of the world’s leading wildlife photographers come to the city’s suburbs, to raise awareness of the species and their fight for survival



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Bags for life carry food poisoning risk if used for raw meat or fish

The Guardian - Mon, 2017-10-02 23:58

Use separate bags for raw foods, ready-to-eat foods, and household products to avoid bacteria spreading, warns food safety watchdog

Reusable “bags for life” can spread deadly food poisoning bacteria if they are used to carry raw foods such as fish and meat, consumers have been warned by the government’s food safety watchdog.

In revised guidance on its website, the Food Standards Agency (FSA) is recommending that shoppers use separate bags to carry raw foods, ready-to eat foods and non-food items such as household cleaners and washing powder.

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Body clock scientists win Nobel Prize

BBC - Mon, 2017-10-02 21:18
Understanding how our bodies keep time has "vast implications" for health, say Nobel committee.
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Wildlife on your doorstep: October

The Guardian - Mon, 2017-10-02 20:33

There will be further autumnal signs in the northern hemisphere now October has shown up, while the southern hemisphere can finally begin to enjoy springtime. We’d like to see your photos of this month’s wildlife near you

For the northern hemisphere the leaves will only get browner, and the ground frostier, with October signalling a further shift towards the colder darker winter months ahead. For the southern hemisphere the month should be pleasant, with new signs of life emerging in the wild and warmer spring sunshine to be enjoyed by all. So what sort of wildlife will we all discover on our doorsteps? We’d like to see your photos of the October wildlife near you.

Share your photos and videos with us and we’ll feature our favourites on the Guardian site.

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Why the 97% climate consensus is important | Dana Nuccitelli, John Cook, Sander van der Linden, Tony Leiserowitz, Ed Maibach

The Guardian - Mon, 2017-10-02 20:00

Some have argued that consensus messaging is counter-productive. Here’s why they’re wrong.

Unfortunately, humans don’t have infinite brain capacity, so no one can become an expert on every subject. But people have found ways to overcome our individual limitations through social intelligence, for example by developing and paying special attention to the consensus of experts. Modern societies have developed entire institutions to distill and communicate expert consensus, ranging from national academies of science to the Intergovernmental Panel on Climate Change. Assessments of scientific consensus help us tap the collective wisdom of a crowd of experts. In short, people value expert consensus as a guide to help them navigate an increasingly complex and risk-filled world.

More generally, consensus is an important process in society. Human cooperation, from small groups to entire nations, requires some degree of consensus, for example on shared goals and the best means to achieve those goals. Indeed, some biologists have argued that “human societies are unable to function without consensus.” Neurological evidence even suggests that when people learn that they are in agreement with experts, reward signals are produced in the brain. Importantly, establishing consensus in one domain (e.g. climate science) can serve as a stepping stone to establishing consensus in other domains (e.g. need for climate policy).

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Coca-Cola increased its production of plastic bottles by a billion last year, says Greenpeace

The Guardian - Mon, 2017-10-02 19:28

Increase puts Coke’s production at more than 110bn single-use plastic bottles a year, according to analysis by the green group

Coca-Cola increased its production of throwaway plastic bottles last year by well over a billion, according to analysis by Greenpeace.

The world’s biggest soft drinks company does not disclose how much plastic packaging it puts into the market. But analysis by the campaign group Greenpeace reveals what they say is an increase in production of single-use PET bottles from 2015-2016.

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UK's longest-lasting patch of snow melts away

BBC - Mon, 2017-10-02 18:14
The UK's hardiest snow patch melts for what is thought to be only the seventh time in 300 years.
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Federal politics: Adani and the Queensland polls

ABC Environment - Mon, 2017-10-02 17:35
Tonight's ABC Four Corners program is expected to detail fresh concerns about the controversial Adani coal mine in central Queensland.
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Poorly insulated homes may cost £1bn extra in energy bills

The Guardian - Mon, 2017-10-02 16:01

Legal loophole means landlords won’t need to comply with regulations aiming to protect tenants and cut carbon emissions

Tenants in the UK’s draughtiest homes risk paying £1bn extra in energy bills because of a government loophole letting landlords off the hook, a charity has warned.

Landlords will be banned from letting poorly insulated homes from next April under new regulations designed to protect vulnerable tenants and cut carbon emissions.

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Natural health service: wildlife volunteers get mental health boost

The Guardian - Mon, 2017-10-02 15:45

Research supports the idea that nature could be widely prescribed by doctors as a therapy, easing the burden on the NHS

Volunteers on wildlife projects benefit from a big boost to their mental health, according to new research. It advances the idea that nature could be widely prescribed by doctors as a therapy, which its supporters say would ease the burden on the NHS.

The new analysis tracked people across England taking part in projects run by the Wildlife Trusts, ranging from nature walks and conservation work to the Men in Sheds project in Bolton, which makes bird tables and bug hotels.

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Sardinia yacht club targets sailors with charter to cut plastic waste

The Guardian - Mon, 2017-10-02 15:30

Charta Smerelda aims to encourage 150,000 sailors to reduce plastic pollution in ocean and protect marine habitats

One of the most exclusive yacht clubs in the world has drawn up an environmental charter to ask 150,000 sailors across the globe to reduce plastic pollution in the ocean.

The Costa Smerelda yacht club in Sardinia, established by the Aga Khan 50 years ago, is publishing the charter to cut plastic waste at the One Ocean Forum conference. International sailing organisations have signed up to support the document which will be disseminated to 150,000 sailors who compete across the world.

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Closing the loop on e-waste

ABC Environment - Mon, 2017-10-02 15:10
An Australian science breakthrough could solve the problem of e-waste recycling and create a network of small business opportunities.
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Country diary: the charged stillness of the kestrel

The Guardian - Mon, 2017-10-02 14:30

Kinder Scout, Derbyshire Kestrel numbers may be in decline but we saw maybe half a dozen hanging in the updraft or plummeting into peat groughs

The perfect wild camping place: an obliging flat spot next to a horseshoe-shaped meander where the stream has carved out a tall bank from the soft shale grit, offering water close to hand and shelter from the wind. Best of all, our tents face towards a slope covered in reefs of purple heather that are being prowled by a kestrel. Though dinner consists of a bag of rehydrated dust, the opportunity to eat while watching a wild bird at work without hurry or distraction makes it feel positively luxurious.

I never fail to be captivated by kestrel flight; the suspenseful hovering, then the sudden swoop, that combination of charged stillness and sudden action that Gerard Manley Hopkins thrilled to in Windhover: “High there, how he rung upon the rein of a wimpling wing… / then off, off forth on swing, / As a skate’s heel sweeps smooth on a bow-bend.” Over an hour or so it makes several apparently unsuccessful plunges into the heather before finally reappearing with a vole in its talons.

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Mercury from the northern hemisphere is ending up in Australia

The Conversation - Mon, 2017-10-02 12:33
Mercury pollution, often released from gold mining and coal power stations, is a global problem. Shutterstock

Mercury pollution has a long legacy in the environment. Once released into the air, it can cycle between the atmosphere and ecosystems for years or even decades before ending up deep in the oceans or land.

The amount of mercury in the ocean today is about six times higher than it was before humans began to release it by mining. Even if we stopped all human mercury emissions now, ocean mercury would only decline by about half by 2100.

To address the global and long-lasting mercury problem, a new United Nations treaty called the Minamata Convention on Mercury came into effect last month. The treaty commits participating countries to limit the release of mercury and monitor the impacts on the environment. Australia signed the Convention in 2013 and is now considering ratification.

Read more: Why won’t Australia ratify an international deal to cut mercury pollution?

Until now, we have only been able to guess how much mercury might be in the air over tropical Australia. Our new research, published in the journal Atmospheric Chemistry and Physics, shows that there is less mercury in the Australian tropics than in the northern hemisphere – but that polluted northern hemisphere air occasionally comes to us.

A global problem

While most of mercury’s health risks come from its accumulation in ocean food webs, its main entry point into the environment is through the atmosphere. Mercury in air comes from both natural sources and human activities, including mining and burning coal. One of the biggest mercury sources is small-scale gold mining – a trade that employs millions of people in developing countries but poses serious risks to human health and the environment.

Small-scale gold mining is an economic mainstay for millions of people, but it releases mercury directly into the air and water sources.

Once released to the air, mercury can travel thousands of kilometres to end up in ecosystems far away from the original source.

Measuring mercury in the tropics

While the United Nations was gathering signatures for the Minamata Convention, we were busy measuring mercury at the Australian Tropical Atmospheric Research Station near Darwin. Our two years of measurements are the first in tropical Australia. They are also the only tropical mercury measurements anywhere in the Maritime Continent region covering southeast Asia, Indonesia, and northern Australia.

We found that mercury concentrations in the air above northern Australia are 30-40% lower than in the northern hemisphere. This makes sense; most of the world’s population lives north of the Equator, so most human-driven emissions are there too.

More surprising is the seasonal pattern in the data. There is more mercury in the air during the dry season than the wet season.

The Australian monsoon appears to be partly responsible for the seasonal change. The amount of mercury jumps up sharply at the start of the dry season when the winds shift from blowing over the ocean to blowing over the land.

In the dry season the air passes over the Australian continent before arriving at the site, while in the wet season the air usually comes from over the ocean to the west of Darwin. Howard et al., 2017 (modified)

But wind direction can’t explain the whole story. Mercury is likely being removed from the air by the intense rains that characterise the wet season. In other words, the lower mercury in the air during the wet season may mean more mercury is being deposited to the ocean and the land at this time of year. Unfortunately, there simply isn’t enough information from Australian ecosystems to know how this impacts local plants and wildlife.

Fires also play a role. Mercury previously absorbed by grasses and trees can be released back to the atmosphere when the vegetation burns. In our data, we see occasional large mercury spikes associated with dry season fires. As we move into a bushfire season predicted to be unusually severe, we may see even more of these spikes.

Air from the north

Although mercury levels were usually low in the wet season, on a few days each year the mercury jumped up dramatically.

To figure out where these spikes were coming from, we used two different models. These models combine our understanding of atmospheric physics with real observations of wind and other meteorological parameters.

Both models point to the same source: air transported from the north.

Australia is usually shielded from northern hemispheric air by a “chemical equator” that stops air from mixing. This barrier isn’t static – it moves north and south throughout the year as the position of the sun changes.

A few times a year, the chemical equator moves so far south that the top end of Australia actually falls within the atmospheric northern hemisphere. When this happens, polluted northern hemisphere air can flow directly to tropical Australia.

We observed 13 days when our measurement site near Darwin sampled more northern hemisphere air than southern hemisphere air. On each of these days, the amount of mercury in the air was much higher than on the days before or after.

Tracing the air backwards in time showed that the high-mercury air travelled over the Indonesian archipelago before arriving in Australia. We don’t yet know whether that mercury came from pollution, fires, or a mix of the two.

The highest mercury is observed when the air comes from the northern hemisphere. Howard et al., 2017 (modified) A global solution

To effectively reduce mercury exposure in sensitive ecosystems and seafood-dependent populations around the world, aggressive global action is necessary.

The cross-boundary influences on mercury that we have observed in northern Australia highlight the need for the type of multinational collaboration that the Minamata Convention will foster.

Our new data establish a baseline for monitoring the effectiveness of new actions taken under the Minamata Convention. With the first Conference of the Parties having taken place last week, hopefully it will only be a matter of time before we begin to see the benefit.

The Conversation

Jenny Fisher receives funding from the Australian Research Council and the L'Oréal-UNESCO For Women in Science Fellowship program.

Peter Nelson received funding from the Commonwealth Department of Environment, Water, Heritage and the Arts. He is co-lead of the UN Environment Partnership on Mercury Control from Coal Combustion.

Dean Howard and Grant C Edwards do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

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The Pears Report: Energy pricing demands a response

RenewEconomy - Mon, 2017-10-02 11:17
When energy assets were being sold off, many politicians thought that people would blame the industry for any problems, not governments. Sorry guys. Everyone knows you write the rules and supposedly enforce them.
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Tesla opens first Adelaide store

RenewEconomy - Mon, 2017-10-02 11:05
Tesla is bringing scalable energy products and services including the award-winning Powerwall to customers with the opening of its first store in Adelaide at Westfield Marion.
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