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Wenlock Edge, Shropshire Birds verminous and ominous, persecuted and mythologised, foolproof, climateproof, futureproof

Two crows fly into a tree towards the end of a long dreamy summer’s day. They had been walking their beat on Windmill Hill, through the flowering cocksfoot, lady’s bedstraw, pyramidal orchids and whitlowgrass, hunting there as they have done every day for 15 years I know of. They now perch together as if watching the sunset, and so do I.

In the same place doing the same thing, what can I know of the corvid mind? We know corvid intelligence is equal to that of primates. We know early people were intimately connected to the crow tribes and there are funerary relics from more than 5,000 years ago containing the bones of crows and ravens buried in this land. This belongs to ancient rituals that suggest a mutual trade in death; these were birds of omen long before they were thought of as vermin.

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Why baseload should not be confused with "reliability" - and why building new coal fired generators - as proposed by conservatives in US and Australia - may make the grid less reliable, and more expensive.

Over the past decade we have seen a substantial increase in our scientific understanding of how climate change affects extreme rainfall events. Not only do our climate models suggest that heavy rainfall events will intensify as the atmosphere warms, but we have also seen these projections start to become reality, with observed increases in rainfall intensity in two-thirds of the places covered by our global database.

Given this, we might expect that the risk of floods should be increasing globally as well. When it comes to global flood damage, the economic losses increased from roughly US$7 billion per year in the 1980s to US$24 billion per year in 2001-11 (adjusted for inflation).

It would be natural to conclude that at least some of this should be attributable to climate change. However, we know that our global population is increasing rapidly and that more people now live in flood-prone areas, particularly in developing countries. Our assets are also becoming more valuable – one only needs to look at rising Australian house prices to see that the values of homes at risk of flooding would be much greater now than they used to be in decades past.

So how much of this change in flood risk is really attributable to the observed changes in extreme rainfall? This is where the story gets much more complicated, with our new research showing that this question is still a long way from being answered.

Are floods on the rise?

To understand whether flood risk is changing – even after accounting for changes in population or asset value – we looked at measurements of the highest water flows at a given location for each year of record.

This sort of data is easy to collect, and as such we have reasonably reliable records to study. There are more than 9,000 streamflow gauges around the world, some of which have been collecting data for more than a century. We can thus determine when and how often each location has experienced particularly high volumes of water flow (called “large streamflow events”), and work out whether its flood frequency has changed.

A streamflow gauging station in Scotland. Jim Barton/Wikimedia Commons, CC BY-SA

We found that many more locations have experienced a decrease in large streamflow events than have experienced an increase. These decreases are particularly evident in tropical, arid, and humid snowy climate regions, whereas locations with increasing trends were more prevalent in temperate regions.

To understand our findings, we must first look closely at the factors that could alter the frequency and magnitude of these large streamflow events. These factors are many and varied, and not all of them are related directly to climate. For example, land-use changes, regulated water releases (through dam operations), and the construction of channels or flood levées could all influence streamflow measurements.

We looked into this further by focusing on water catchments that do not have large upstream dams, and have not experienced large changes in forest cover that would alter water runoff patterns. Interestingly, this barely changed our results – we still found more locations with decreasing trends than increasing trends.

The Australian Bureau of Meteorology and similar agencies worldwide have also gone to great lengths to assemble “reference hydrological stations”, in catchments that have experienced relatively limited human change. Studies that used these sorts of stations in Australia, North America and Europe are all still consistent with our findings – namely that most stations show either limited changes or decreases in large streamflow events, depending on their location.

What can we say about future flood risk?

So what about the apparent contradiction between the observed increases in extreme rainfall and the observed decreases in large streamflow events? As noted above, our results don’t seem to be heavily influenced by changes in land use, so this is unlikely to be the primary explanation.

An alternative explanation is that, perhaps counterintuitively, extreme rainfall is not the only cause of floods. If one considers the 2010-11 floods in Queensland, these happened because of heavy rainfall in December and January, but an important part of the picture is that the catchments were already “primed” for flooding by a very wet spring.

Perhaps the way in which catchments are primed for floods is changing. This would make sense, because climate change also can cause higher potential moisture loss from soils and plants, and reductions in average annual rainfall in many parts of the world, such as has been projected for large parts of Australia.

This could mean that catchments in many parts of the world are getting drier on average, which might mean that extreme rainfall events, when they do arrive, are less likely to trigger floods. But testing this hypothesis is difficult, so the jury is still out on whether this can explain our findings.

Despite these uncertainties, we can be confident that the impacts of climate change on flooding will be much more nuanced than is commonly appreciated, with decreases in some places and increases in others.

Your own flood risk will probably be determined by your local geography. If you live in a low-lying catchment close to the ocean (and therefore affected by sea level rise), you’re probably at increased risk. If you’re in a small urban catchment that is sensitive to short sharp storms, there is emerging evidence that you may be at increased risk too. But for larger rural catchments, or places where floods are generally caused by snow melt, the outcome is far harder to predict and certain locations may see a decrease in flooding.

All of this means that a one-size-fits-all approach is unlikely to be suitable if we are to allocate our resources wisely in adjusting to future flood risk. We must also think about the effects of climate change in a broader context that includes changes to land-use planning, investment in flood protection infrastructure, flood insurance, early warning systems, and so on.

Only by taking a holistic view, informed by the best available science, can we truly minimise risk and maximise our resilience to future floods.

Seth Westra receives funding from the Australian Research Council, the Water Corporation of Western Australia and the Goyder Institute.

Hong Xuan Do does 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.

Over the past two years The Conversation has published my analyses on a range of topics related to climate change and politics, including climate denial in the Liberal Party, 25-year-old cabinet papers (not once but twice), coal industry PR campaigns and much else besides. Finally comes a topic I can cheerfully say I know nothing about (at first hand, at least): raising children.

Apologies for oversharing, but I had a vasectomy in 2004. The columnist Andrew Bolt spotted this, via an article in Britain’s Daily Mail which clearly stated that I was the one who had been under the knife. Bolt claimed that my wife had “sterilised herself”. (She does a lot of yoga, but she’s not that flexible. We have pointed this out but Bolt has kept at it, repeating the claim almost six years later).

Despite what the Daily Mail article says (and what is within the quotes was never said), our decision not to have kids wasn’t based on concern for what our hypothetical children would do to the planet, but rather what the planet would do to them. My wife copped some online abuse, and I was once disinvited to appear on the BBC after explaining my actual position.

I first switched on to climate change in about 1989, and have become convinced that the second half of the 21st century will probably make the first half of the 20th look like a golden age of peace and love. There have been 30 years of promises and pledges, protocols and agreements, while atmospheric greenhouse gas levels have climbed remorselessly due to humanity’s emissions. I suspect that the reported recent flatlining in emissions growth could well turn out to be as illusory as the so-called global warming “hiatus”.

Writing recently in the Sydney Morning Herald, climate scientist Sophie Lewis eloquently asked:

Should we have children? And if we do, how do we raise them in a world of change and inequity? Can I reconcile my care and concern for the future with such an active and deliberate pursuit of a child? Put simply, I can’t.

While I would never presume to tell anyone what to do with their genitals, I must confess my personal amazement that climate activists who do have children - and who I know have read the same scientific research as me and drawn the same conclusions – aren’t freaking out more. (Perhaps they are just very tired.)

As the Manic Street Preachers sagely warned, our children will have to tolerate whatever we do, and more besides.

Be prepared?

So how do we prepare tomorrow’s adults for the world bequeathed to them by the adults of yesterday and today? Even the mainstream media is beginning to ask this question.

Some studies say young people don’t care enough about climate change; others claim they do. The Australian picture seems to be mixed.

As the environmental writer Michael McCarthy has lamented:

A new edition of the Oxford Junior Dictionary was published in 2007 with a substantial group of words relating to nature – more than 50 – excised: they included acorn, adder, ash, beech, bluebell, buttercup, catkin, conker, cowslip and dandelion. Their replacements included terms from the digital world such as analogue, blog, broadband, bullet-point, celebrity, chatroom, cut-and-paste, MP3 player and voicemail.

Might we be more adaptive than we think? The social demographers Wolfgang Lutz and Raya Muttarak, in their snappily titled paper Forecasting societies’ adaptive capacities through a demographic metabolism model, think so, describing how “the changing educational composition of future populations” might help societies adapt to climate change.

But not everyone thinks our brains will get us out of the mess that they and our opposable thumbs have got us into. As an editor at the Daily Climate pointed out:

A substantial portion of the human population lives on coasts. Much of their protein comes from fish. What happens when ocean acidification turns all of that to slime?

So what should we tell kids about climate?

It always helps to be open to advice from different settings. For instance, I stumbled on this good advice on a blog aimed at military spouses, but it strikes me that it holds just as true for the climate-concerned:

It is okay to show sadness around your kids; in fact, it is probably healthy. However, it is not okay to dump your emotions on them. Save rants and deep conversations for trusted adults.

If you are feeling overwhelmed (and you will), don’t turn to your kids. Children are usually helpless to offer advice and it can cause them to experience anxiety. Seek help from an adult friend … extended family, a neighbor, your church, or a counselor.

Sophie Lewis sensibly hopes that the next generation(s) “can be more empathetic, more creative and more responsive than we have been”. It’s a noble hope, but it will only happen if we behave differently.

So as previously in this column, it’s over to you, the readers. I have a couple of questions for you:

First, how do those of you who are parents (and grandparents, aunts and uncles) talk to your children about the climate change impacts that will happen in their lifetimes? Avoidance? Sugar-coating? The “straight dope”? Do you slip books from the burgeoning fields of dystopian fiction and “cli-fi” into their Christmas stockings? Besides The Hunger Games, there is Tomorrow, When the War Began, the excellent Carbon Diaries and, more recently, James Bradley’s The Silent Invasion. Do you worry about scaring the kids? What do the youngsters themselves say?

Second, what steps are you taking to help young people develop the (practical and interpersonal) skills required to survive as times get tougher? What are those skills? How do we make sure that it isn’t just the few (children of the rich and/or the “switched on”) who gain these skills?

ASX Announcement in relation to Genex’s Kidston renewable energy project in North Queensland.

Solar pioneer David Mills says if he can do it, almost anyone can. And by doing “it”, he means powering his house and his two electric vehicles largely through rooftop solar, and storing excess output in battery storage

The UK's favourite yellow submarine completes its first major science expedition in the Antarctic.

Vegetable grower Nectar Farms says its decision to use 100% renewable energy for the country’s biggest glasshouse project will deliver major cost savings over traditional use of gas and grid power. “Really, why would you do it any differently,” its CEO says.

US energy secretary says "baseload" coal is critical to functioning of the grid. Energy regulator says that is "absolutely not" the case.

The French floating PV specialist is building a 70 MW solar facility in China’s Anhui province.

The Australian Heritage Council is assessing St Kilda Road and Environs for potential permanent inclusion in the National Heritage List. Comments close 11 August 2017.

The Australian Heritage Council is assessing St Kilda Road and Environs for potential permanent inclusion in the National Heritage List. Comments close 11 August 2017.

In an excerpt from his book on Australian birdlife, Geoffrey Maslen finds there’s method in magpies’ madness

Hostilities have broken out up and down the east coast of Australia. The enemy strikes from above, and always attacks from behind. Casualties have been reported and the dive bombings that began with the onset of spring have become more frequent. Zoologists have been called in to devise some means of defence but they have also suffered from the swift and silent enemy.

Related: Penguin Bloom: how a scruffy magpie saved a family

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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.

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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.

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