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What's the role and responsibility of public health professionals in protecting the public's 'right to health' in an age of unprecedented global warming?

Before building a new coal fired, nuclear or renewable power station, Australia should look at energy efficiency first, says visiting expert Benoit Lebot

This year is unlikely to be a brilliant butterfly summer because 2016 was so poor. But insects can rapidly bounce back

Spring is an unquenchably optimistic time, and two weeks of plentiful sunshine – in the south, at least – has brought out the first butterflies of the year. My first, like last year, was a male brimstone, bobbing beside the old ivy-covered hedge beyond my garden.

On the next sunny March day came the small tortoiseshells and peacocks, which also hibernate as adult butterflies. It wasn’t until 2 April that I saw my first orange tip and holly blue – species which burst afresh from their chrysalises with the warming weather.

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Former Barrier Reef authority director Jon Day says the idea such an approach would save the reef from bleaching is ‘ridiculous’

A proposal to use $9m to pump cold water on to the Great Barrier Reef’s tourist hotspots to stave off coral bleaching has been described as a “band-aid” solution, which does little to address the fundamental threats to the world’s largest living structure.

The plan, proposed by the tourism industry and the Reef and Rainforest Research Centre, seeks to protect six reefs with high economic or environmental value near Cairns and Port Douglas.

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The devastating flood damage wreaked by Tropical Cyclone Debbie has left many residents in northern New South Wales facing an enormous cleanup that could take months.

Any Lismore local will tell you that flooding is a fact of life in the Northern Rivers. In the floods of 1954 and 1974, the Wilsons River rose to a record 12.17 metres. This time around, the river peaked at 11.59m, breaching the flood levee built in 2005 for the first time.

So what are the conditions that caused those historic floods? And are they any different to the conditions of 2017?

Like the current flood, cyclonic rains also caused the 1954 and 1974 events. But unlike those past events, both of which were preceded by prolonged wet weather, almost all of the extreme rainfall from ex-Tropical Cyclone Debbie fell within 24 hours.

More interesting still is the fact that we are not currently experiencing La Niña conditions, which have historically formed the backdrop to severe flooding in eastern Australia.

The 1954 flood was preceded by an east coast low from February 9-11, followed by a decaying tropical cyclone from February 19-22. Thirty people were killed as flood records were set in Lismore, Kyogle, Casino, Nimbin and Murwillumbah. Some places received more than 1,000mm of rain in 14 days.

In 1974, former Tropical Cyclone Zoe unleashed torrential rain over Lismore, Wyrallah and Coraki. From March 10-13, some stations received almost 1,000mm in just four days. One analysis described the flood as a once-in-70-year event.

This time around, the remains of Tropical Cyclone Debbie delivered extreme rainfall to northern NSW towns including Murwillumbah, Chinderah and Lismore, despite having crossed the coast several days earlier and more than 1,200km to the north. Floods as far apart as Rockhampton in central Queensland and northern New Zealand show the storm’s colossal area of influence.

During the event, 20 rainfall stations in Queensland and 11 sites in NSW recorded their wettest March day on record. Mullumbimby, in the Brunswick River catchment, received a staggering 925mm during March – over half the annual average in a single month – causing major flooding in the region.

The heaviest rainfall in the Wilsons River catchment was at Terania Creek, which received 627mm over March 30-31, 99% of it in the 24 hours from 3am on March 30. Lismore recorded 324.8mm of rain in the 18 hours to 3am on March 31, its wettest March day in more than 100 years. A little further out of town, floodwaters submerged the gauge at Lismore Airport, so unfortunately we do not have reliable figures for that site.

March 2017 rainfall across Australia. Tropical Cyclone Debbie’s track down the east coast is visible in the trail of above-average falls. Bureau of Meteorology

The main difference between the current flooding and the 1954 and 1974 floods is that the previous events both occurred against a background of sustained La Niña conditions. These tend to deliver above-average tropical cyclone activity and high rainfall totals, which increase flood risk.

During the early 1970s, Australia experienced the longest period of La Niña conditions in the instrumental record. This unleashed phenomenal deluges across virtually the entire country. By the end of 1973, many catchments were already saturated as the wet season started early, culminating in the wettest January in Australia’s rainfall records.

In 1974 the Indian Ocean was also unusually warm (what meteorologists call a “negative Indian Ocean Dipole (IOD) phase”), further enhancing rainfall in the region. When negative IOD events coincide with La Niña conditions in the tropical Pacific, the warm sea temperatures reinforce one another, resulting in more evaporation and increased rainfall. This double whammy resulted in the exceptionally wet conditions experienced across the country during 1974.

In January 1974, the Northern Territory, Queensland and Australia as a whole recorded their wettest month on record, while South Australia and New South Wales recorded their second-wettest January on record. Torrential monsoon rains in the gulf country of Queensland transformed the normally dry interior into vast inland seas, flooding all the way to Lake Eyre in the arid zone of South Australia.

Vast swathes of Australia were much wetter than average during the mid-1970s. Bureau of Meteorology

In contrast, Tropical Cyclone Debbie formed under neutral conditions, rather than during a La Niña. In fact, the Bureau of Meteorology is currently on El Niño watch, meaning that there is double the normal risk of an El Niño event bringing low rainfall and high temperatures to Australia by mid-2017.

So, unlike the 1950s and 1970s, the current flooding happened despite the absence of conditions that have driven major flooding in the past. It seems extraordinary that such a damaging cyclone could develop under these circumstances, and deliver such high rainfall over such a short time. This suggests that other factors may be at play.

A rapidly warming climate means that storms are now occurring in a “super-charged” atmosphere. As temperatures increase, so does the water-holding capacity of the lower atmosphere. The oceans are also warming, especially at the surface, driving up evaporation rates. Global average surface temperature has already risen by about 1℃ above pre-industrial levels, leading to an increase of 7% in the amount of water vapour in the atmosphere.

Ocean evaporation, before and after ocean warming. Climate Council

Of course, it is hard to determine the exact impact of climate change on individual storms. However, climate scientists are confident about the overall trends.

Australia’s land and oceans have warmed by 1℃ since 1910, with much of this warming occurring since 1970. This influences the background conditions under which both extremes of the rainfall cycle will operate as the planet continues to warm. We have high confidence that the warming trend will increase the intensity of extreme rainfall experienced in eastern Australia, including southeast Queensland and northern NSW.

While it will take more time to determine the exact factors that led to the extreme flooding witnessed in March 2017, we cannot rule out the role of climate change as a possible contributing factor.

CSIRO’s latest climate change projections predict that in a hotter climate we will experience intense dry spells interspersed with periods of increasingly extreme rainfall over much of Australia. Tropical cyclones are projected to be less frequent but more intense on average.

That potentially means longer and more severe droughts, followed by deluges capable of washing away houses, roads and crops. Tropical Cyclone Debbie’s formation after the exceptionally hot summer of 2016-2017 may well be a perfect case in point, and an ominous sign of things to come.

Joelle Gergis receives funding from the Australian Research Council.

Astronomers make the first detection of an atmosphere surrounding a "super-Earth" planet.

Study shows almost all farms could significantly cut chemical use while producing as much food, in a major challenge to the billion-dollar pesticide industry

Virtually all farms could significantly cut their pesticide use while still producing as much food, according to a major new study. The research also shows chemical treatments could be cut without affecting farm profits on over three-quarters of farms.

The scientists said that many farmers wanted to reduce pesticide use, partly due to concerns for their own health. But farmers do not have good access to information on alternatives, the researchers said, because much of their advice comes from representatives of companies that sell both seeds and pesticides.

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UN celebrates fall in renewables costs but warns that investment is slipping

ALIEN SOLAR SYSTEM: Australian volunteer citizen scientists find four previously unknown planets orbiting a nearby star thanks to a crowd-sourcing project aired on the ABC's Stargazing Live.

Animal welfare advocates have filmed some of the wild elephants captured in Zimbabwe last year and shipped to China

Last year more than 30 young elephants were captured from the wild in Zimbabwe and flown by plane to China. The elephants – some reported to be as young as three – were dispersed to a number of zoos throughout the country, including the Shanghai Exhibition Park, the Beijing Wildlife Park and the Hangzhou Safari Park, according to conservationists.

But what are their lives like now?

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Amazon's founder and CEO Jeff Bezos is investing $1bn (£801m) a year to fund his Blue Origin company.

Green groups say the Resgen Boikarabelo project in South Africa will lead to worker exploitation and hinder Paris commitments

Environmental action groups including Greenpeace, Oxfam and GetUp have signed an open letter to Australia’s export credit agency asking it not to fund a controversial new coal mine.

The groups say a loan to the proposed Resgen Boikarabelo mine in South Africa will lead to human rights abuses and hinder Australia’s Paris commitment to keep global warming below 2C.

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Ruling by South Africa’s highest court means rhino horns can be sold locally by traders holding permits

South Africa’s highest court has rejected a bid by the government to keep a ban on domestic trade in rhino horn, a court document shows.

The ruling by the constitutional court effectively means rhino horns may be traded locally.

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Aerial footage shows severe flooding in the New Zealand town of Edgecumbe in the North Island on Thursday, after the tail-end of ex-cyclone Debbie brought two days of heavy rain and burst river banks. Thousands of people have been evacuated and states of emergency have been declared in numerous regions of the North Island

• New Zealand towns hit by ‘once in 500-year flood’ as storm system sweeps in
  

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Electricity bills have doubled in the last five years. In fact, in the last decade Australia has gone from having almost the cheapest power in the world to some of the most expensive.

Electricity bills have doubled in the last five years. In fact, in the last decade Australia has gone from having almost the cheapest power in the world to some of the most expensive.

A diving expedition off Easter Island (or Rapa Nui) in the Pacific pushes the boundaries of both technology and the human body to reveal a world of unique species just waiting to be discovered

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Study finds three-quarters of consumers throw away rather than recycle or donate unwanted garments

A predicted 235m items of Britons’ unwanted clothing are expected to end up in landfill unnecessarily this spring, according to new research.

Three-quarters of consumers admit to binning their discarded garments, usually because they do not realise that worn-out or dirty clothes can be recycled or accepted by charities, a survey of 2,000 people commissioned by the supermarket Sainsbury’s has found.

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Newly introduced limits on rooftop solar and battery storage capacities could motivate some households to go at least partially off-grid. - potentially bringing forward the much discussed death spiral. Meanwhile, a regulator warns that system upgrades will require the entire system to meet latest standards.

Going off-grid is a big step. It requires careful consideration, good design and engaged users.