Feed aggregator

There are just four breeding pairs of the iconic bird of prey left in England.

There is no question now that solar and wind will dominate the future of electricity. The question is how fast.

'Tropics' may conjure images of sun-kissed islands, but the expanding tropical zone could bring drought and cyclones further south. Pedro Fernandes/Flickr, CC BY-SA

The Tropics are defined as the area of Earth where the Sun is directly overhead at least once a year — the zone between the Tropics of Cancer and Capricorn.

However, tropical climates occur within a larger area about 30 degrees either side of the Equator. Earth’s dry subtropical zones lie adjacent to this broad region. It is here that we find the great warm deserts of the world.

Earth’s bulging waistline

Earth’s tropical atmosphere is growing in all directions, leading one commentator to cleverly call this Earth’s “bulging waistline”.

Since 1979, the planet’s waistline been expanding poleward by 56km to 111km per decade in both hemispheres. Future climate projections suggest this expansion is likely to continue, driven largely by human activities – most notably emissions of greenhouse gases and black carbon, as well as warming in the lower atmosphere and the oceans.

If the current rate continues, by 2100 the edge of the new dry subtropical zone would extend from roughly Sydney to Perth.

As these dry subtropical zones shift, droughts will worsen and overall less rain will fall in most warm temperate regions.

Poleward shifts in the average tracks of tropical and extratropical cyclones are already happening. This is likely to continue as the tropics expand further. As extratropical cyclones move, they shift rain away from temperate regions that historically rely upon winter rainfalls for their agriculture and water security.

Researchers have observed that, as climate zones change, animals and plants migrate to keep up. But as biodiversity and ecosystem services are threatened, species that can’t adjust to rapidly changing conditions face extinction.

In some biodiversity hotspots – such as the far southwest of Australia – there are no suitable land areas (only oceans) for ecosystems and species to move into to keep pace with warming and drying trends.

We are already witnessing an expansion of pests and diseases into regions that were previously climatically unsuitable. This suggests that they will attempt to follow any future poleward shifts in climate zones.

I recently drew attention to the anticipated impacts of an expanding tropics for Africa. So what might this might mean for Australia?

IPCC Australia is vulnerable

Australia’s geographical location makes it highly vulnerable to an expanding tropics. About 60% of the continent lies north of 30°S.

As the edge of the dry subtropical zone continues to creep south, more of southern Australia will be subject to its drying effects.

Meanwhile, the fringes of the north of the continent may experience rainfall and temperature conditions that are more typical of our northern neighbours.

The effects of the expanding tropics are already being felt in southern Australia in the form of declining winter rainfall. This is especially the case in the southwest and — to a lesser extent — the continental southeast.

Future climate change projections for Australia include increasing air and ocean temperatures, rising sea levels, more hot days (over 35℃), declining rainfall in the southern continental areas, and more extreme fire weather events.

For northern Australia, changes in annual rainfall remain uncertain. However, there is a high expectation of more extreme rainfall events, many more hot days and more severe (but less frequent) tropical cyclones and associated storm surges in coastal areas.

Dealing with climate change

Adaptation to climate change will be required across all of Australia. In the south the focus will have to be on adapting to projected drying trends. Other challenges include more frequent droughts, more warm spells and hot days, higher fire weather risk and rising sea levels in coastal areas.

The future growth of the north remains debatable. I have already pointed out the lack of consideration of climate change in the White Paper for the Development of Northern Australia.

The white paper neglects to explain how planned agricultural, mining, tourism and community development will adapt to projected changes in climate over coming decades — particularly, the anticipated very high number of hot days.

For example, Darwin currently averages 47 hot days a year, but under a high carbon emission scenario, the number of hot days could approach 320 per year by 2090. If the north is to survive and thrive as a significant economic region of Australia, it will need effective climate adaptation strategies. This must happen now — not at some distant time in the future.

This requires bipartisan support from all levels of government, and a pan-northern approach to climate adaptation. It will be important to work closely with industry and affected local and Indigenous communities across the north.

These sectors must have access to information and solutions drawn from interdisciplinary, “public good” research. In the face of this urgent need, CSIRO cuts to such research and the defunding of the National Climate Change Adaptation Research Facility should be ringing alarm bells.

As we enter uncharted climate territory, never before has public-good research been more important and relevant.

Steve Turton has previously received funding from the Australian Government.

Mud oysters played a largely unappreciated part in Australia's history. Cayne Layton, Author provided

The largest oyster reef restoration project outside the United States is underway in the coastal waters of Gulf St Vincent, near Ardrossan in South Australia. Construction began earlier this month. Some 18,000 tonnes of limestone and 7 million baby oysters are set to provide the initial foundations for a 20-hectare reef.

The A$4.2-million project will be built in two phases and should be complete by December 2018. The first phase is the 4-hectare trial currently being built by Primary Industries and Regions South Australia; the second phase will see the reef expand to 20 hectares, led by The Nature Conservancy.

Some of the 18,000 tonnes of limestone destined for the seafloor. D. McAfee

Just 200 years ago the native mud oyster, Ostrea angasi, formed extensive reefs in the Gulf, along more than 1,500km of South Australia’s coastline. Today there are no substantial accumulations of mud oysters anywhere around mainland Australia, with just one healthy reef remaining in Tasmania.

This restoration project aims to pull our native mud oyster back from the brink of extinction in the wild, and restore a forgotten ecosystem that once teemed with marine life.

More than just seafood

Oysters played a large role in Australia’s colonial history. When European settlers first arrived they had to navigate a patchwork of oyster reefs (also called shellfish reefs) that filled the shallow waters of our temperate bays. These enormous structures could cover 10 hectares in a single patch, providing an easily exploited food resource for the struggling early settlers. Oyster shell was burned to produce lime, and the colony’s first buildings were built with the help of oyster cement.

Collectively, these pre-colonial oyster reefs would have rivalled the geographic extent of the Great Barrier Reef, covering thousands of kilometres of Australia’s eastern and southern coastlines.

The history goes back much further too. For thousands of years oyster reefs fed and fuelled trade among Aboriginal communities. Shell middens dating back 2,000 years attest to the cultural importance of oysters for coastal communities, who ate them in abundance and used their shells to fashion fishhooks and cutting tools.

Health oyster reef in Tasmania. C. Gillies

The insatiable appetite of the newly settled Europeans for this bountiful resource was devastating. Not only were live oysters harvested for food, but the dead shell foundations that are critical for the settlement of new oysters were scraped from the seabed for lime burning. Armed with bottom-dredges a wave of exploitation spread across the coast, first overexploiting oyster reefs close to major urban centres and then further afield. The combination of the lost hard shell bed and increased sediment runoff from the rapidly altered coastal landscape saw oyster populations crash within a century of colonisation.

Today oyster populations are at less than 1% of their pre-colonial extent in Australia. This is not a unique story – globally it is estimated that 85% of oyster habitat has been lost in the past few centuries, making it one of the most exploited marine habitats in the world.

Today, across much of Australia’s east coast you will see Sydney rock oysters encrusting rocky shores, creating a thin veneer around the edge of our bays and estuaries. On the south coast you occasionally see a solitary mud oyster clinging to a jetty pylon. Many Australians don’t realise that this familiar sight represents a mere shadow of the incredible and largely forgotten ecosystems that oysters once supported.

Oysters are an unsung ecological superhero, with the capacity to increase marine biodiversity, clean coastal waters, enhance neighbouring seagrass, reduce coastal erosion, and even slow the rate of climate change. When oysters cement together, their aggregations form habitat for a great diversity of other invertebrates. A 25cm-square patch of oysters can host more than 1,000 individual invertebrates from a range of different biological groups, in turn providing a smorgasbord for fish.

Restoration site, formerly covered with dense oyster habitat. D. McAfee

A solitary oyster can filter about 100 litres of water a day, which means that en masse they can function as the “kidneys” of our bays, filtering excess nutrients from the water and depositing them on the seafloor. In doing so, they encourage seagrass growth, while their physical structures help to dissipate wave energy and thus reduce the impact of storm surges.

As if all that weren’t enough, oysters are also a carbon sink, building calcium carbonate shells that are buried in the seafloor after death and eventually compacted to rock, thus helping to prevent carbon dioxide from cycling back into the atmosphere.

Building it back

Restoring oyster reefs has the potential to return these ecosystem services and increase the productivity of our coastal ecosystems. The Gulf of St Vincent project came about through an election promise by the South Australian Government to boost recreational fishing. A collaboration between The Nature Conservancy, Yorke Penninsula Council and the South Australian Government will deliver the reef’s foundations, while my colleagues and I at the University of Adelaide are working to ensure that the restored oysters survive and thrive, and that the reef continues to grow.

Hopefully this is just the beginning for large-scale oyster restoration in Australia, and the lessons learned from this project will guide more restoration projects to improve the health of our oceans. With other restoration projects also underway in Victoria and Western Australia, the tide is hopefully turning for our once numerous oysters.

Sean Connell receives funding from The Ian Potter Foundation and Department of Environment Water and Natural Resources and The Environment Institute of The University of Adelaide for this research.

Dominic McAfee 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.

Environmental Protection Agency and army propose ending clean water rule to hold ‘substantive re-evaluation’ of which bodies of water should be protected

The Environmental Protection Agency is poised to dismantle the federal clean water rule, which protects waterways that provide drinking water for about a third of the US population.

The EPA, with the US army, has proposed scrapping the rule in order to conduct a “substantive re-evaluation” of which rivers, streams, wetlands and other bodies of water should be protected by the federal government.

Continue reading...

Journalist Angela Saini argues that it's easy for prejudice to affect scientific research.

The restoration of the ozone hole, which blocks harmful radiation, will be delayed by decades if fast-rising emissions of dichloromethane are not curbed

The restoration of the globe’s protective shield of ozone will be delayed by decades if fast-rising emissions of a chemical used in paint stripper are not curbed, new research has revealed.

Atmospheric levels of the chemical have doubled in the last decade and its use is not restricted by the Montreal protocol that successfully outlawed the CFCs mainly responsible for the ozone hole. The ozone-destroying chemical is called dichloromethane and is also used as an industrial solvent, an aerosol spray propellant and a blowing agent for polyurethane foams. Little is known about where it is leaking from or why emissions have risen so rapidly.

Continue reading...

The government pledges to pay its "fair share" towards an EU backed nuclear project after Brexit.

Amy Dickman has had some close shaves with big cats and humans while working with cheetahs and lions.

African Development Bank president Akinwumi Adesina wins the prestigious World Food Prize for his work to boost yields and farm incomes.

Data collected from an air pollution monitoring station in Tasmania is showing rising carbon dioxide levels in the atmosphere.

A Greenpeace expedition around Scottish coastlines has found plastic in the feeding grounds of basking sharks, in the habitats of puffins, seals and whales, and in the nests and beaks of seabirds

Continue reading...

A Greenpeace research expedition into plastic waste finds devastating pollution on Scottish beaches and seabird colonies

Plastic bottles and packaging are overrunning some of the UK’s most beautiful beaches and remote coastline, endangering wildlife from basking sharks to puffins.

A Greenpeace research ship has spent the past two months touring the Scottish coast and islands assessing the impact of plastic waste.

Continue reading...

Fourteen critical bottlenecks, from roads to ports to shipping lanes, are increasingly at risk from climate change, say analysts

Increasingly vulnerable “chokepoints” are threatening the security of the global food supply, according to a new report. It identifies 14 critical locations, including the Suez canal, Black Sea ports and Brazil’s road network, almost all of which are already hit by frequent disruptions.

With climate change bringing more incidents of extreme weather, analysts at the Chatham House thinktank warn that the risk of a major disruption is growing but that little is being done to tackle the problem. Food supply interruptions in the past have caused huge spikes in prices which can spark major conflicts.

Continue reading...

Allendale, Northumberland Every now and then I hear the peep of what sounds like a single owlet, but I can’t be sure

It can take a while for owls to accept a nest box. My homemade wooden one was built to a chimney design from the RSPB website and set on a sycamore branch at the recommended 45-degree angle. My garden has a plentiful supply of voles, which are owls’ main prey. I have waited five years for one to move in.

For the past couple of weeks, the signs had been there: hysterical blackbird calls and a fluster of blackcaps and dunnocks signalling the daytime presence of a tawny owl in my garden. I have watched her edging closer to the box as the days have passed, first on a level spur of the ash tree, next on the side branch of a sycamore, and then so near the house that I could study her as I ate my breakfast.

Continue reading...

On same day as major industrial project goes 100% renewables, Abbott calls for freeze on RET, ban on wind farms, and for government to build a new coal generator.

Hydro Tasmania has reached in-principle agreement to buy electricity from the proposed Granville Harbour wind farm on Tasmania’s west coast.

New York grid operator says future grid will not only become more decentralized and de-carbonized, but it will increasingly be bi-directional, if not multi-directional.

Australians overwhelmingly want our country’s energy system to be powered by renewables because they see it as the “economically smart” thing for Australia’s future.

Victoria’s Ararat Wind Farm was officially opened today with a ceremony in Ararat to mark the completion of the 240MW wind farm.