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Herbivorous tropical fish in the remains of a kelp forest in northern New South Wales, Australia. A University of NSW study found the disappearance of kelp from waters near Coffs Harbour coincided with a 0.6 degree temperature rise that had the ‘truly catastrophic’ effect of attracting increased numbers of hungry fish

• Destruction of kelp forests by tropical fish shows impact of ocean temperature rises

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The UK's most famous dinosaur skeleton will start its national tour on England's Jurassic Coast.

One of Australia’s most experienced energy leaders, Nino Ficca, has been elected as the new Chair of Energy Networks Australia.

Sungrow has held a series of energy storage training roadshows in Australia aimed at promoting its next generation hybrid inverter SH5K+.

Panasonic's new 5.3kWh lithium-ion batteries will be available to Australian households from December.

KELP KILLERS: The southerly migration of voracious tropical fish and urchins are threatening kelp forests along the east coast of Australia, while marine heatwaves and pollution are taking their toll in the south and west, two separate studies have found.

The journal Climatic Change has published a special edition of review papers discussing major natural hazards in Australia. This article is one of a series looking at those threats.

Australia is a huge continent, but a coastal nation. About 80% of Australians live within 50km of the coast, and a sea-level rise of 1.1 metres (a high-end scenario for 2100) would put about A$63 billion (in 2008 dollars) worth of residential buildings at risk.

Anyone who lives along Sydney’s northern beaches, especially in Collaroy, saw at first hand the damage the ocean can wreak on coastal properties when the coastline was hit by a severe east coast low during a king tide in June.

There are many different factors that determine which coastal homes or suburbs are most at risk of inundation or erosion, either now or in the future. In a review published as part of a series produced by the Australian Energy and Water Exchange initiative, we investigated the causes of extreme sea levels and coastal impacts in Australia, how they have changed, and how they might change even more. While significant progress has been made over recent decades, many questions remain.

The first factor to consider is the average sea level, relative to the land elevation. This “background” sea level varies, both from year to year and season to season. Depending on where you live and what the climate is doing, background sea level can fluctuate by up to about 1m. Around Australia’s northern coastline, for example, El Niño and La Niña can cause large variations in year-to-year sea levels.

On top of this are the tides, which rise and fall predictably, and whose range varies by location and phase of the moon. Most places have two tides a day, but curiously some only have one - including Perth.

On top that again is the effect of the weather, the most notable short-term effects being storm surges and storm waves. During a surge, the storm pushes extra water onto the coast through a combination of wind pressure, wave buildup, and atmospheric pressure changes. Obviously these factors are much more localised than tides.

Extreme sea-level events, such as the one that hit Sydney in June, can arise from isolated events such as a storm surge. But more often they are due to a combination of natural phenomena that on their own may not be considered extreme. In Sydney, several factors aligned: a storm surge driven by an east coast low, an uncommon wave direction, a king tide, and a higher-than-average background sea level.

These processes already have the capacity to destroy coastal homes and infrastructure. But for the future, we also need to factor in climate change, which will raise the background sea level and may also change the frequency and intensity of storms.

Long-term trends

Average sea levels in Australian waters have been rising at rates similar to (but just below) the global average. Since 1993, Australian tide gauges show an average rise of 2.1mm per year, whereas satellite observations reveal a global average rise of 3.4mm per year.

What really counts is extreme sea levels, and these have been rising at roughly the same rate, meaning that the rising background sea level is a fairly good guide to how extremes are increasing.

The effects of a king tide on Queensland’s Gold Coast. Bruce Miller/CSIRO, CC BY

This trend will continue in the future, although more energetic storm systems may also cause larger storm surges and hence higher rates of extreme sea levels in some places. More frequent storms are also set to make extreme sea-level events more common.

By 2100, global average sea level is projected to rise by 0.28-0.61cm, relative to the period 1986-2005, if this century’s global warming can be held to about 1℃. But if greenhouse emissions continue to increase at their current rate, the world is in line for sea-level rises of 0.52-0.98cm.

This rise will not be uniform around Australia’s coastline. The east coast is likely to experience up to 6cm more sea-level rise than the global average by 2100, because of the expected warming and strengthening of the East Australian Current.

Trends in Australia’s weather and waves are harder to predict. Satellite measurements over the past 30 years suggest that waves are getting slightly higher in the Southern Ocean, and climate models suggest that this may continue. As the tropics continue to expand with climate change, the band of westerly winds over the Southern Ocean will retreat further south and strengthen, whipping up higher waves that will travel to Australia’s southern coast as swell. On the other hand, weakening winds nearer to Australia may help to dampen down wave heights. On Australia’s eastern coast, climate models suggest fewer large wave events due to decreasing storminess in the Tasman Sea in the future.

A significant challenge we face is not having the data available to monitor the changes along our southern coastline. Australia has the longest east-west continental shelf in the world, but we have only a handful of wave buoys to measure these processes; much of the coastline is not monitored despite widespread coastal management concerns.

Our understanding of extreme sea-level change in Australia is also limited by available tide gauge coverage. Only two digital tide gauge records (in Fremantle and Fort Denison) extend back to at least the early 20th century, and records elsewhere around the coast typically span less than 50 years.

However, our investigation discovered that there is an opportunity to increase the length of available records by digitising old paper tide gauge charts. This could extend several records along our southern and tropical coastlines.

We also have major gaps in our knowledge about how our coastlines will be changed by flooding and erosion. The simple methods used to predict coastal erosion may underestimate erosion significantly, particularly in estuaries.

Given the considerable urban infrastructure located within estuaries, and the fact that they are vulnerable both to coastal storms and river floods, this is one of the many crucial questions about life on the coast that we still need to answer.

Kathleen McInnes works for CSIRO Oceans and Atmosphere, and receives funding from the Commonwealth of Australia Department of the Energy and Environment National Environmental Science Program, through the Earth Systems and Climate Change Hub, and the Australian Renewable Energy Agency.

Mark Hemer works for CSIRO Oceans and Atmosphere, and receives funding from the Commonwealth of Australia Department of the Energy and Environment National Environmental Science Program, through the Earth Systems and Climate Change Hub, and the Australian Renewable Energy Agency.

Ron Hoeke works for CSIRO Oceans and Atmosphere, and receives funding from the Commonwealth of Australia Department of the Energy and Environment National Environmental Science Program, through the Earth Systems and Climate Change Hub, and the Australian Renewable Energy Agency.

The Australian wave energy company’s new hub is the world’s largest and most advanced for developing offshore renewable energy technology

Carnegie Wave Energy’s offshore energy-generating infrastructure is purposefully inconspicuous. Its patented CETO buoys, which resemble large circular tanks, are tethered to an anchor in the seafloor and remain fully submerged, out of sight.

It’s a design feature that prioritises long-term survival in the ocean over efficiency in converting energy, says Michael Ottaviano, Carnegie’s managing director.

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Kelp forests are declining around the world and in Australia, according to two new studies.

The first, a global study published in the journal PNAS, found that 38% of the world’s kelp forests have declined over the past 50 years.

The second, published in the same PNAS edition, investigated one cause of the declines. Kelp forests in eastern Australia are losing out to tropical species as the seas warm.

Together the studies show that we need local and global solutions to prevent our underwater forests from vanishing.

Deep trouble

Satirist Jordan Shanks recently argued that marine biologists may well have the worst job on Earth. Although most people think we spend our days diving in crystal-clear blue waters, spotting whales and sailing into the sunset, this is actually quite far from the truth.

More often than not, our job unfortunately involves documenting the depressing deterioration and decline of precious marine habitats.

While bleaching of coral reefs worldwide has been front and centre in the news over the past year, in fact all of our coastal ecosystems have been affected by human impacts.

One such ecosystem is the underwater forests formed by the large seaweeds known as kelp, which dominate temperate, coastal rocky shores worldwide.

Kelp forests are found in waters off all continents, and around Australia they form the Great Southern Reef which stretches from the Queensland border to near Kalbarri in Western Australia, and contributes more than A$10 billion annually to the Australian economy.

Although this year’s global coral bleaching event has been most featured in the media, we should be at least equally concerned about the loss of kelp forests in cooler waters. Clockwise from top left: A. Vergés, Creative Commons, J. Turnbull, A. Vergés A health check for global kelp forests

In the first study, the authors provide the first ever global “health check” for kelp forests. A team of international experts compiled and analysed a data set of kelp abundance at more than 1,000 sites across 34 regions around the globe.

While 38% of the world’s kelp forests have declined, it isn’t all bad news. Just over 25% of kelp forests have actually increased in abundance.

But there is another big problem: there are many regions where kelp exists, but we have no data and simply no idea how it’s doing.

A kelp forest in South Africa. The species Ecklonia maxima is one of the few kelps that are expanding its distribution. This species is ‘the giant cousin’ of the common kelp in Australia, Ecklonia radiata. T. Wernberg

Unfortunately, Australia’s kelp forests feature heavily among the declining populations. Kelp forests have declined in Western Australia, South Australia, Tasmania and New South Wales. The causes of this loss are diverse, but share a common factor: people.

In Western Australia kelp forests were wiped out during an extreme marine heatwave, which was probably a consequence of climate change. In South Australia, the kelp has succumbed to years of pollution from nutrient-rich wastewater.

And in Tasmania, warming has enabled a kelp-eating sea urchin to jump from the mainland and graze on local kelp forests. This was compounded by overfishing of large lobsters, which normally eat the urchins.

Turning tropical

The second paper shows that a phenomenon known as “tropicalisation” of ecosystems is now threatening kelp forests in New South Wales, and potentially globally.

Tropicalisation occurs as ocean waters warm and tropical species start making a home in habitats previously dominated by cold-water species. In the case of NSW kelp forests, these tropical intruders are herbivorous fishes that eat the kelp – sometimes down to the ground.

Our initial research has shown that, over ten years, lush kelp forests have completely disappeared in some key offshore sites at the Solitary Islands Marine Park. This region is famous for bringing together a unique mosaic of tropical and temperate habitats, but our data clearly shows that tropical species are winning and starting to take over.

Screen grabs from Baited Remote Underwater Videos collected by Dr Hamish Malcolm, showing dense kelp beds back in the early 2000s that completely disappeared from 2010 onwards. Hamish Malcolm

We were able to quantify the year-by-year decline of kelp using a long-term video dataset collected by Hamish Malcolm from the NSW Department for Primary Industries.

The video footage revealed not only the gradual decline of kelp, but also helped us identify fish as central culprits behind this disappearance. Between 2002 and 2012, we saw both an increase in the number of fish bite marks on kelp and a clear rise in the abundance of warm-water seaweed-eating species.

We also ran a series of kelp transplant experiments, which identified two warm-water fish species that rapidly consumed transplanted kelp within hours: a rabbitfish and a drummer.

Interestingly, however, the species that we think had the greatest effect, surgeonfish, did not actually feed on the adult kelp. Instead, the surgeonfish rapidly consumed smaller carpet-forming seaweeds. This suggests these “tropicalising” fishes maintain deforested reefs by removing kelp while they are tiny, before they start making large fronds.

These NSW findings are by no means an isolated phenomenon. Voracious consumption by invading warm-water fish have also been linked to the loss or failure to recover of kelp forests in Japan and in Western Australia.

Frenzied feeding on transplanted kelp by a school of rabbitfish (Siganus fuscescens) is only briefly interrupted by a large predator in the Solitary Islands, eastern Australia. What can we do?

Both studies found a net decline in the abundance of kelp forests, from both local (nutrients, fishing) and global (ocean warming and its effects) effects of humans. If we want to arrest these declines, action is therefore required at both local and global scales.

Locally, water quality around some major cities has been improved. When coupled with active restoration efforts of damaged seaweeds, this can lead to conservation success stories like the return of crayweed forests to Sydney. Marine reserves, where fishing is prohibited, can also reduce the ability of warm-water species to colonise cooler habitats.

But of course, ultimately, global action is needed to prevent further climate change impacts. That includes reduction in our greenhouse gas emissions, in Australia and around the world.

Adriana Vergés receives funding from the Australian Research Council.

Peter Steinberg receives funding from the Australian Research Council.

Thomas Wernberg receives funding from The Australian Research Council and The Hermon Slade Foundation.

Indigenous rangers have joined efforts to get to the bottom of this year's unprecedented mass dieback of mangroves in the Gulf of Carpentaria.

An exceptionally rapid melt this summer has led to unusually high water temperatures in the Arctic Sea, slowing the progress of fresh ice formation

Residents of the Alaskan city of Barrow (due to change its name to Utqiaġvik on 1 December) would normally be looking out across a frozen harbour by now, but this year the sea is reluctant to freeze.

Barrow’s average temperature for October 2016 was a balmy -1C, significantly warmer than the long-term average of around -8C. And over the North Pole the air has been a full 10C warmer than average of late.

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Energy efficiency is the 'cheapest and cleanest' form of fuel—and countries are increasingly realising it's a resource they haven't tapped into, says the International Energy Agency.

Deforestation near Coffs Harbour coincided with 0.6C temperature rise, which had ‘catastrophic’ effect of attracting fish

Herbivorous tropical fish have destroyed kelp forests in northern New South Wales, showing that even small increases in ocean temperature can lead to kelp deforestation, an Australian study has found.

The University of NSW study, published in the Proceedings of the National Academy of Sciences on Tuesday, found that the disappearance of kelp from waters near Coffs Harbour coincided with a threefold increase in the number of tropical fish in the region.

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Election of climate science denier Donald Trump could speed up talks to preserve elements of the Paris agreement

“People were walking around looking pretty shellshocked,” says Dr Bill Hare, perched on a chair in the cavernous media tent at the United Nations climate talks in Morocco. “If you hugged an American there was a good chance they’d burst into tears.”

Donald Trump’s triumph in the US elections cast a shadow over the first week of the 22nd round of talks here in Marrakech. The president-elect has pledged to pull the US out of the global climate agreement – signed by all countries in Paris last year to keep global warming “well below 2C”.

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Calls for a tax on meat and dairy products (Report, 8 November) are misguided and would increase, not decrease, overall emissions from agriculture. Instead we should improve production systems by taxing nitrogen fertiliser and pesticides, the underlying causes of environmental damage associated with food systems.

Something close to mass hysteria has developed in relation to cattle and other ruminants since the publication in 2006 of Livestock’s Long Shadow, by the Food and Agriculture Organisation. This report and its successor in 2013 are both flawed and misleading. They conflate the emissions from the destruction of virgin land in South America, the root cause of which is not chicken production, but our insatiable demand for vegetable oils, with the actual emissions from ruminants. They also failed to balance this by including emissions from the conversion of land to grow crops for human consumption, or the carbon sequestration associated with the planting of forests in parts of the world, such as the UK, that was taking place at the same time.

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Sydney Renewable Power Company to sell 519 shares after International Convention Centre deal to buy all electricity produced

The company responsible for Australia’s biggest CBD solar installation has invited public investment, making it the first community renewables project in Australia with a public share offering.

Sydney Renewable Power Company’s 520kW solar installation on top of the new International Convention Centre in Darling Harbour is the size of 12 tennis courts and will generate enough electricity to power about 100 homes each year.

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While prestigious routes are well-maintained, smaller footpaths under the care of local councils are suffering from budget cuts - and it’s these we need the most

The largest ever survey of footpaths in England and Wales has found that almost half are in need of improvement, with a tenth of the 140,000-mile network in serious disrepair. For anyone, like me, who considers a decent yomp a staple of any good weekend, those results won’t seem in the least bit surprising.

Of the 59,000 problems reported by the 3,250 citizen surveyors who took part in the Ramblers’ Big Pathwatch, a third were for missing signposts that can quickly turn a pleasant country stroll into an epic trudge as the detours mount up. But most were for obstructions, like barbed wire and collapsed bridges, or footpaths made impassable by flooding and overgrowth that would likely force you to abandon your walk altogether.

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ClimateHome: Failings on the part of the bank contributed to ‘real and often severe harm’ to villagers around the Sibovc mine, says leaked report

The World Bank broke its own rules and contributed to the suffering of hundreds of Kosovans who were forced from their homes to make way for a coalmine, a leaked report reveals.

The giant state-owned Sibovc mine has swallowed communities as it expanded. It would supply the only coal power plant on earth the World Bank is considering backing.

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From drought-hit Nigeria to wine-growing Finland, we hear from people whose lives have already been changed by a warming world

• 2016 will be the hottest year on record, UN says

In the displacement camps of north-east Nigeria, most residents have the same answer for why 2.6 million people have been forced from their homes in this region. They are running from Boko Haram, the jihadist militants who still control significant parts of the Lake Chad basin.

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Native Americans fear that the Dakota Access oil pipeline – a $3.7bn project that would carry crude oil from the Bakken oil field in North Dakota to a refinery in Patoka, Illinois – would contaminate sacred lands and their water supply from the Missouri river. Here, protesters at a camp near the Standing Rock Sioux reservation give their views on what the election of Donald Trump might mean for their campaign

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