Friday, 31 March 2017

The plight of the brainy bumblebee

For our bumblebees, it seems being smart comes at a cost.

Odd findings just published by Kiwi, UK and Canadian researchers show that bumblebees that learn faster have a much shorter foraging lifespan than their slow-learning co-workers.

They also found that the fast-learning bumblebees collected food at rates comparable to the less cognitively able in the colony and completed a similar number of foraging bouts per day.

"Our results are surprising, because we typically associate enhanced learning performance and cognitive ability with improved fitness, because it is considered beneficial to the survival of an individual or group," said study co-author Dr Lisa Evans, of New Zealand's Plant and Food Research.
"This study provides the first evidence of a learning-associated cost in the wild."

The researchers evaluated the visual learning performance of 85 individual foraging bumblebees across five different colonies - subjecting them to an ecologically realistic colour and reward association task in the laboratory and then monitoring their performance in the wild using radio frequency identification tagging technology.

Tuesday, 28 March 2017

Expect fewer cyclones, but the ones that form will pack a wallop

There was a point earlier this summer when Aussies in the Top End started to wonder: Where the hell are the cyclones?

The Australian region is usually hit with 11 cyclones each season - which runs from November 1 to April 30 - but only five tropical cyclones have been named in 2016-17. The 2015-16 season was the least active on record, with only three tropical cyclones declared.
In other words, it has been eerily still.

That was until today, when a Category 4 monster will hurtle towards the Whitsundays.
The region is expected to endure destructive winds, gales and a dangerous storm surge when the cyclone hits this morning.

The latest research into cyclones suggests that this will become the norm: fewer cyclones, but the ones that do form will be destructive.

That means stronger winds, more ferocious storms and heavier rain.

Cyclones need a very specific set of conditions in the atmosphere and ocean to form. Climate change has made those conditions harder to find, which is likely to lead to fewer tropical cyclones around the world, according to University of Melbourne cyclone expert Associate Professor Kevin Walsh.

One of the key conditions is sea-surface temperature above 26.5C and cool conditions in the upper part of the troposphere, which is found 15km above sea level.

"Climate change is causing the upper troposphere to heat up even more, and so the atmosphere becomes more stable," Dr Walsh told the university's Pursuit website.

Sunday, 26 March 2017

Great Barrier Reef: 'See it while you still can'

A leading Kiwi climate scientist has a message for people wanting to visit Australia's Great Barrier Reef: see it now before it's too late.

Dr Jim Salinger said the "burning, drying and flooding" continent was now experiencing dramatic impacts from climate change.

"The iconic Great Barrier Reef, already badly damaged by global warming during three extreme heatwaves, in 1998, 2002 and 2016, is being yet damaged by a new bleaching event is under way now," said Salinger, currently an honorary research fellow at Otago University's Department of Geography.

"The extreme marine heatwave in 2016 killed two-thirds of the corals along a 700km stretch of the northern Great Barrier Reef, from Port Douglas to Papua New Guinea.

"It caused dramatic change for the reef and that climate change is here now.

"The message is simple - visit it now otherwise if we see more diebacks of corals in the next few years, little if any action on emissions and inadequate progress on water quality, then an 'in danger' listing in 2020 as a World Heritage area."

Salinger said the past summer had brought prolonged and at times extreme heat over New South Wales, southern Queensland, South Australia and parts of northern Victoria.

The three heatwaves across January and early February saw unusually high daily maximum and minimum temperatures for at least three consecutive days over large parts of the country.

During these heatwaves, daily maximum temperatures across southeast Australia exceeded 40C over very large areas and were typically 8C to 12C above the January and February averages.

Tuesday, 21 March 2017

NZ's future: Zero emissions by 2100?

Slashing pastoral stock numbers by up to 35 per cent has been suggested among ways to push New Zealand's greenhouse gas emissions down to zero by 2100.

A cross-party group of MPs have commissioned UK consultants Vivid Economics to look at the options, which have been presented as four bold scenarios for the country in a new report launched today.

Under the first scenario, the country would further slash the emissions intensity of its economic activity through technological advances, such as cost reductions in electric vehicles for freight, electric heating technologies for high temperature applications and a vaccine to reduce methane emissions from pastoral agriculture.

This would be accompanied by a structural shift away from pastoral agriculture - with animal numbers around 20 to 35 per cent lower than today - to less emissions-intensive activity.

The country would instead support a diverse range of land uses, including horticulture and crops, alongside extensive planting of forests, covering an extra million hectares of land by 2050.

This scenario could result in a 70 to 80 per cent reduction in net emissions compared with current levels, however the authors said this option still relied upon breakthroughs like high-grade heat and non-passenger transport, along with extra tech in the agriculture sector.

Under a second scenario, an extra 1.6 million hectares of forest planted by 2050 would "substantially reduce emissions" - a 65 to 75 per cent reduction - and provide opportunities in a significantly enhanced forest products industry.

"However, changed land uses may require a difficult transition for rural economies, as well as represent a lost opportunity to reintroduce native habitat."

Saturday, 18 March 2017

Tackling global warming key to saving Great Barrier Reef

The survival of the Great Barrier Reef rests on cutting global warming, with efforts to improve water quality and fishing doing little to prevent major bleaching, according to a new study.

The study, released in the scientific journal Nature, shows protecting it from fishing and poor water quality is doing little to prevent bleaching.
"Global warming is the number one threat to the reef. The bleaching in 2016 strongly reinforces the urgent need to limit climate change," said co-author David Wachenfeld from the Great Barrier Reef Marine Park Authority.

The reef experienced the worst coral bleaching on record last summer with protective efforts making no difference to the amount of bleaching during the extreme weather.

"With rising temperatures due to global warming, it's only a matter of time before we see more of these events," Wachenfeld said.

Thursday, 16 March 2017

Half of Arctic sea ice decline due to natural causes, says new study

A new study has found that as much as half of the decline in Arctic sea ice over the last several decades was due to natural causes, rather than human interaction.

And a New Zealand climate expert says the findings show how variability in the Arctic and Antarctica might not be so different after all.

Although human interaction is still a major factor in the decline, the study shows the sea ice is less sensitive to our interactions than initially thought.

"It is well recognised that recent Arctic sea-ice decline has both natural and anthropogenic drivers, but their relative importance is poorly known," said the research, published online in Nature Climate Change.

The study was conducted by Qinghua Ding from the University of California, and his colleagues.
It focused on atmospheric circulation in the summer months and how it influenced the extent of Arctic summer sea ice in September.

"We have provided a plausible mechanism for how circulation changes can impact Arctic sea ice, but it is difficult to determine causality with observational evidence alone, because of the feedbacks between sea ice and the atmosphere," the study said.

Researchers were able to conduct several model experiments to show how high-latitude circulation impacted sea ice.
The researchers found 30 to 50 per cent of the overall decline in September Arctic sea ice since 1979 could be accounted for by natural variability.

Tuesday, 14 March 2017

Villagers at mercy of rising sea levels

When the waves surrounded her first house Vasney Aitoaea was frightened. She could hear them crashing around her, and she prayed to God she would survive.

"That first house fell down," she says. "So my husband built a second near the same place. And then the waves came again. And so we built a third, and a fourth, each time further up the beach."
She looks out to the ocean, flat and oily in the grey light.

"The first house was over there, where the sun is on the sea."

She is pointing about 40m behind her, to a rock that will be covered by water at high tide, but which used to be the edge of the island Kwai, a tiny atoll in the Solomon Islands suffering the effects of a warming ocean.
Vasney Aitoaea, 71, from the island of Kwai, has had to move and rebuild her home five times due to the rise in sea level. Photo / Mike Scott
Rates of sea-level rise in the Solomons over the past two decades were among the highest in the world, averaging around 8mm a year between 1993 and 2012 - compared to below 2mm per year in New Zealand.

Some of the rise in that time has been attributed to natural climate variability, such as El Nino, and the increase has now flattened to 3.6mm a year. But already five islands in the Solomons, a country of 600,000 in remote Melanesia, have disappeared into the Pacific. A further six are so severely eroded that families have had to be relocated, including a whole village. Others have seen salt-water intrusion to the point crops will no longer grow, according to an Australian study published last year.

Kwai, a tiny, white-sand atoll off the east coast of the island Malaita, is one of those at risk.
Community leader Francis Robeni says the island has been eroded to the point it is now small and crowded.

"This island before was a fairly beautiful island," he says. "It stretched out further, 20 or 30m out that way. But during the cyclones, the big seas, the currents it started to erode.

Sunday, 12 March 2017

Exposure to pollution 'kills millions of children'

Exposure to polluted environments is associated with more than one in four deaths among children younger than 5, according to two World Health Organisation reports published today.

Worldwide, 1.7 million children's deaths are attributable to environmental hazards, such as exposure to contaminated water, indoor and outdoor pollution, and other unsanitary conditions, the reports found.

Weaker immune systems make children's health more vulnerable to harmful effects of polluted environments, the report says.

Some of the most common causes of death among children, such as malaria, diarrhea and pneumonia, can be prevented by implementing ways known to reduce environmental risks and exposure to these risks, the first report shows. About one quarter of all children's deaths and diseases in 2012 could have been prevented by reducing environmental risks.

Exposure to polluted environments is also dangerous during pregnancy because it increases the chances of premature birth. Infants and preschool children exposed to indoor and outdoor pollution are at a higher risk of contracting pneumonia and chronic respiratory diseases. The likelihood of cardiovascular diseases, cancer and stroke also significantly increases with exposure to polluted environments.

The second report quantifies the problem by providing the number of children who died because of exposure to polluted environments.

According to the report, every year:

- 570,000 children under 5 years die from respiratory infections, such as pneumonia, attributable to indoor and outdoor air pollution and second-hand smoke - smoke that is released by burning tobacco products, such as cigarettes.

Friday, 10 March 2017

By 2030, half the world's oceans could be reeling from climate change, scientists say

More than half the world's oceans could suffer multiple symptoms of climate change over the next 15 years, including rising temperatures, acidification, lower oxygen levels and decreasing food supplies, new research suggests.

By the mid-century, without significant efforts to reduce warming, more than 80 per cent could be ailing - and the fragile Arctic, already among the most rapidly warming parts of the planet, may be one of the regions most severely hit.

The study, published today in the journal Nature Communications uses computer models to examine how oceans would fare over the next century under a business-as-usual trajectory and a more moderate scenario in which the mitigation efforts promised under the Paris Agreement come into effect. In both scenarios, large swaths of the ocean will be altered by climate change.

Nearly all of the open sea is acidifying because of greenhouse gas emissions. But the researchers found that cutting greenhouse gas emissions could significantly delay future changes, giving marine organisms more time to migrate or adapt.

"Things that live in the ocean are used to regular variability in their environments," said lead study author Stephanie Henson, a scientist at the National Oceanography Centre at the University of Southampton in Britain. "It gets warm in the summer and it gets cold in the winter, and species survive that kind of range in temperature or other conditions perfectly well."

But she noted a warming climate could eventually cause changes in the ocean that have never happened before - hotter temperatures, lower pH or less oxygen than have ever naturally occurred. When this happens, some organisms may no longer be able to tolerate the changed conditions and will be forced to migrate, evolve as a species or face possible extinction.

There's a large degree of uncertainty in the scientific community about how organisms will react. But there's evidence to suggest major challenges ahead. Mass coral bleaching events in the past few years have been largely attributed to unusually warm water temperatures. Large-scale coral death on the Great Barrier Reef last year is thought to be strongly linked to climate change.

Wednesday, 8 March 2017

Rhino tragedy gets too close to home with poaching at zoo

For the past decade, poachers have killed rhinoceroses in the wild and in protected reserves around the world at alarming rates, threatening the survival of four of the world's five rhino species.

The poaching is driven by a demand for rhino horns in southeast Asia that has grown nearly insatiable; so much so, experts say, that any living rhino - anywhere in the world - is now at risk of being killed.

Perhaps no rhino death illustrates that threat more forcefully than the killing of Vince, a 4-year-old male white rhino who was slaughtered this week inside his enclosure at a zoo outside Paris. The rhino - discovered by his keeper at the Thoiry Zoological Park today - now holds the ominous distinction of likely being the first rhino to be killed by poachers inside a zoo, experts said.

"This is the first time we've heard of it," said Crawford Allen, senior director of Traffic North America, a regional office of the World Wildlife Fund (WWF).
"It's certainly the first time it's happened in Europe.

"It's an incredibly shocking and distressing occurrence," he added. "It's also a game-changer for zoos. They've woken up today and realised their world has changed if they have live rhinos in their collection."

In a statement posted on Facebook, the Thoiry Zoological Park, which is 50km west of Paris, said its "entire staff is extremely shocked" by Vince's killing. The animal was born in a zoo in the Netherlands in 2012 and arrived at Thoiry in March 2015, the zoo said.

The zoo pinned the killing on criminals who forced open an outer gate outside the rhinoceros building overnight. The intruders then forced open a second metal door and broke open "an intermediate inner door" that allowed them access to the animal lodges, the zoo said.

Thursday, 2 March 2017

Climate change could reverse sharp drop in the number of fatal large-scale disasters in New Zealand - study

Climate change could challenge the downward trend of large-scale fatal disasters in New Zealand.

A University of Otago study in Wellington analysed sudden events in New Zealand between 1900 and 2015 that caused at least 10 deaths.

Its findings were published in the Australian and New Zealand Journal of Public Health.

It found a sharp drop in the number of fatal large-scale events, from 21 between 1900 and 1919, to just three between 2000 and 2015.

It also found that earthquakes were our most lethal natural disaster, with an average of four deaths a year over the 115-year period covered by the study.

Public health researcher Professor Nick Wilson, who led the research with associate professor George Thomson, put the drop down to safer transportation.

People had found much safer ways of getting around, he said.

"They were largely driven by the reduction in transport-related events. So, ships sinking, trains crashing, aircraft crashing.

"This transportation category reduction probably reflects a large number of factors, such as improvements in vehicle design, marine and aircraft navigation systems, weather forecasting and safety systems in general."

But the downward trend may not last forever, Wilson said.

"In the future, it's still uncertain, because climate change does seem to be happening rapidly.