Battling the seven-headed hydra: Crassula control in Europe

8 11 2016
Hydra. Seba Albertus (1734-1765). Image from Wellsome Trust

Hydra. Seba Albertus (1734-1765). Image from Wellsome Trust

A contribution by Claire Wordley of Conservation Evidence.

The Australian swamp stonecrop (Crassula helmsii) is a small, unassuming looking plant with incredible resilience. It can survive both baking heat and freezing cold; it can live underwater, on the water’s surface and on land; it can survive being dried out, bleached and sprayed with hot foam; and it can regenerate from tiny fragments. Unfortunately, in the UK and elsewhere in Europe it is an invasive species, choking the oxygen from ponds and shading out other plants with knock-on effects for entire freshwater ecosystems.

Swamp stonecrop, also known as New Zealand pigmyweed, was first introduced to the UK from Tasmania in 1911 and sold in garden centres from 1927 as an ornamental pond oxygenator. Shockingly, despite being documented as an invasive plant in New Forest ponds as early as 1976, its sale in the UK was only banned in 2014. Crassula appears to be spread mostly by people, whether deliberately or accidentally; it appears to be concentrated around car parks, residential areas and areas where equipment such as fishing gear is likely to have come from an infected site. Nearly 20% of 700 UK waterbodies surveyed contained the weed. Since every 10% increase in Crassula corresponds to a 5% decrease in native vegetation, and negative effects of Crassula invasion have been documented for zooplankton, macro-invertebrates and fish, with possible negative impacts on amphibians as well, control and ideally eradication is clearly needed. But what works to destroy this superweed?

Killing the hydra

Crassula helmsii (photo by Benjamin Blondel)

Crassula helmsii (photo by Benjamin Blondel)

Like the seven-headed hydra of legend, Crassula helmsii seems able to regenerate after even harsh treatment and being shattered into tiny pieces. Documenting clearly what works to control this beast – and what does not – is critical. This work has recently been completed by Conservation Evidence at the University of Cambridge, as part of an ongoing series on controlling freshwater invasives. The team has worked to collect all the evidence on different ways of killing Crassula, and experts have scored these for their effectiveness (or otherwise).

One of the most effective ways to knock back Crassula appears to be applying herbicides, particularly glyphosate and diquat or diquat alginate. While each of these performed well to reduce Crassula in many trials – and the use of glyphosate and diquat together led to a 98% reduction in one trial – there are concerns that while the medicine could cure the disease, it could kill the patient. One study in the New Forest noted that native plant cover fell in the treatment sites at a greater rate than in the control sites, and glyphosate appears to be toxic to amphibians. There might also be adverse effects on some bird species, although this could be due more to habitat-level changes than direct toxicity, because other birds appeared to benefit from wetlands being sprayed with glyphosate. Read the rest of this entry »





Potential conservation nightmare unfolding in South Africa

31 10 2016

fees-must-fallLike most local tragedies, it seems to take some time before the news really grabs the overseas audience by the proverbial goolies. That said, I’m gobsmacked that the education tragedy unfolding in South Africa since late 2015 is only now starting to be appreciated by the rest of the academic world.

You might have seen the recent Nature post on the issue, and I do invite you to read that if all this comes as news to you. I suppose I had the ‘advantage’ of getting to know a little bit more about what is happening after talking to many South African academics in the Kruger in September. In a word, the situation is dire.

We’re probably witnessing a second Zimbabwe in action, with the near-complete meltdown of science capacity in South Africa as a now very real possibility. Whatever your take on the causes, justification, politics, racism, or other motivation underlying it all, the world’s conservation biologists should be very, very worried indeed.

Read the rest of this entry »





Cartoon guide to biodiversity loss XXXIX

20 10 2016

Six more biodiversity cartoons coming to you all the way from Sweden (where I’ve been all week). See full stock of previous ‘Cartoon guide to biodiversity loss’ compendia here.

Read the rest of this entry »





World’s greatest conservation tragedy you’ve probably never heard of

13 10 2016

oshiwara_riverI admit that I might be stepping out on a bit of a dodgy limb by claiming ‘greatest’ in the title. That’s a big call, and possibly a rather subjective one at that. Regardless, I think it is one of the great conservation tragedies of the Anthropocene, and few people outside of a very specific discipline of conservation ecology seem to be talking about it.

I’m referring to freshwater biodiversity.

I’m no freshwater biodiversity specialist, but I have dabbled from time to time, and my recent readings all suggest that a major crisis is unfolding just beneath our noses. Unfortunately, most people don’t seem to give a rat’s shit about it.

Sure, we can get people riled by rhino and elephant poaching, trophy hunting, coral reefs dying and tropical deforestation, but few really seem to appreciate that the stakes are arguably higher in most freshwater systems. Read the rest of this entry »





Massive yet grossly underestimated global costs of invasive insects

4 10 2016
Portrait of a red imported fire ant, Solenopsis invicta. This species arrived to the southeastern United States from South America in the 1930s. Specimen from Brackenridge Field Laboratory, Austin, Texas, USA. Public domain image by Alex Wild, produced by the University of Texas "Insects Unlocked" program.

Portrait of a red imported fire ant Solenopsis invicta. This species arrived to the southeastern USA from South America in the 1930s. Specimen from Brackenridge Field Laboratory, Austin, Texas, USA. Public domain image by Alex Wild, produced by the University of Texas “Insects Unlocked” program.

As many of you already know, I spent a good deal of time in France last year basking in the hospitality of Franck Courchamp and his vibrant Systematic Ecology & Evolution lab at Université Paris-Sud. Of course, I had a wonderful time and was sad to leave in the end, but now I have some hard evidence that I wasn’t just eating cheese and visiting castles. I was actually doing some pretty cool science too.

Financed by BNP-Paribas and Agence Nationale de Recherche, the project InvaCost was designed to look at the global impact of invasive insects, including projections of range dynamics under climate change and shifting trade patterns. The first of hopefully many papers is now out.

Just published in Nature Communications, I am proud that many months of hard work by a brilliant team of ecologists, epidemiologists and economists has culminated in this article entitled Massive yet grossly underestimated costs of invasive insects, which in my opinion is  the first robust analysis of its kind. Despite some previous attempts at estimating the global costs of invasive species1-4 (which have been largely exposed as guesswork and fantasy5-10), our paper rigorously treats the economic cost estimates and categorises them into ‘reproducible’ and ‘irreproducible’ categories.

Lymantria

Gypsy moth (Lymantria dispar) adult. Dimitri Geystor (France)

What we found was sobering. If we look at just ‘goods and services’ affected by invasive insects, the annual global costs run at about US$70 billion. These include agricultural, forestry and infrastructure damages, as well as many of the direct costs of clean-up and eradication, and the indirect costs of prevention. When you examine that number a little more closely and only include the ‘reproducible’ studies, the total annual costs dip to about US$25 billion, meaning that almost 65% of the costs recorded are without any real empirical support. Scary, especially considering how much credence people put on previously published global ‘estimates’ (for example, see some citation statistics here).

Coptotermes_formosanus

Formosan subterranean termite Coptotermes formosanus by Scott Bauer, US Department of Agriculture, Agricultural Research Service

There’s a great example to illustrate this. If you take it at face value, the most expensive invasive insect in the world is the Formosan subterranean termite Coptotermes formosanus estimated at US$30.2 billion/yr globally. However, that irreproducible estimate is based on a single non-sourced value of US$2.2 billion per year for the USA, a personal communication supporting a ratio of 1:4 of control:repair costs in a single US city (New Orleans), and an unvalidated assumption that the US costs represent 50% of the global total.

Read the rest of this entry »





Valuing what we have to prevent it from disappearing

30 09 2016
29 year-old 'Tembo' shows us his grinders © CJA Bradshaw

29 year-old ‘Tembo’ shows us his grinders. Groom Anton is making sure Tembo remains well-rewarded for his good behaviour © CJA Bradshaw

I acknowledge that I’ve been banging on a bit about southern Africa over the last few weeks, but I defend my enthusiasm on the grounds that my first trip to the Kruger National Park profoundly changed the way I view extinction theory and conservation biology.

Today’s post rounds off this mini-series with something I only alluded to in my last: interacting with tame elephants.

I have always been in two minds about the role of animals in captivity, with my opinion that most zoos edge toward the negative because most people who attend them appear to view the animals as a freak-show rather than appreciate their beauty or be fascinated by their behaviour and ecology; add the near-impossible-to-avoid psychological distress to which most captive animals succumb, many zoos in particular are probably better off not existing at all.

That being the case, I won’t simply write off all captive situations as ‘negative’, because if done well, they can have a wonderful educational role to play. Read the rest of this entry »





Transition from the Anthropocene to the Minicene

24 09 2016
Going, going ...

Going, going … © CJA Bradshaw

I’ve just returned from a life-changing trip to South Africa, not just because it was my first time to the continent, but also because it has redefined my perspective on the megafauna extinctions of the late Quaternary. I was there primarily to attend the University of Pretoria’s Mammal Research Institute 50thAnniversary Celebration conference.

As I reported in my last post, the poaching rates in one of the larger, best-funded national parks in southern Africa (the Kruger) are inconceivably high, such that for at least the two species of rhino there (black and white), their future persistence probability is dwindling with each passing week. African elephants are probably not far behind.

As one who has studied the megafauna extinctions in the Holarctic, Australia and South America over the last 50,000 years, the trip to Kruger was like stepping back into the Pleistocene. I’ve always dreamed of walking up to a grazing herd of mammoths, woolly rhinos or Diprotodon, but of course, that’s impossible. What is entirely possible though is driving up to a herd of 6-tonne elephants and watching them behave naturally. In the Kruger anyway, you become almost blasé about seeing yet another group of these impressive beasts as you try to get that rare glimpse of a leopard, wild dogs or sable antelope (missed the two former, but saw the latter). Read the rest of this entry »





Staggering rhino poaching in the Kruger

14 09 2016

rhino-poachingI have the immense honour and pleasure of attending the University of Pretoria’s Mammal Research Institute 50th Anniversary Celebration conference currently being held in the Kruger National Park. To be rubbing shoulders with some of the greats of African ecology is humbling to say the least, but it’s also a huge opportunity to learn about the wonderful wildlife Africa still has.

Stepping back into what the Pleistocene must have been like in Australia, Europe, and North and South America, I’m moved to near tears by the truly awesome1 megafauna that still exists here. This is my first time to Africa, and I cannot begin to capture how I feel by seeing these amazing species in the flesh.

But as you probably already know, this last megafauna is under huge threat, and we seriously risk repeating the extinctions of the other continents within less than a century. While the topics associated with the threats are diverse, complex and challenging, one talk here stood out for me among all others: that by Ken Maggs of SANParks.

Kruger holds about 70% of the white (Ceratotherium simum) and black (Diceros bicornis) rhino in South Africa, and about 30% all rhino in the world (98.8% of all white rhino are found in just four countries: South Africa, Namibia, Zimbabwe and Kenya).

So for the ~ 10,000 rhino in Kruger, the following numbers should shock you; Ken showed a slide with the following information: Read the rest of this entry »





Conservation is many things to many people

6 09 2016

635927434268884923-480894926_Odyssey5I’ve never really entered the so-called (i.e., contrived) ‘debate’ regarding New Conservation, because I’ve always felt in my gut that it was a false dichotomy (turns out, I’m not the only one to think this). For this reason principally, I haven’t really examined the associated to and fro with any great interest or depth.

I will say this though — I was horrified last year in August while attending the International Congress for Conservation Biology (ICCB) in Montpellier during and after the now-infamous plenary debate between Kareiva and Spash on this ‘New Conservation’. Horrified. Yes.

Peter Kareiva, in his characteristic style, attempted to explain his position in what could be called a deliberately provocative and perhaps sensationalist manner. Clive Spash, on the other hand, took an almost quasi-religious idealogy and used it to smack Peter in the proverbial gob. It was a circus from the start, and unfortunately so badly moderated that neither side came off looking very good at all. The final, and dare I say, sycophantic standing ovation after Spash’s spittle-flecked sermon made me just a little sick to my stomach.

Really? Was all this swaggering, Shakespearean posturing justified? Is the discipline of conservation biology at a philosophical and ideological crossroads requiring its respective disciples to choose their favourite messiah from a binomial distribution? I didn’t think so then, and I’m even less inclined to think so now.

It was something of a vindication of that now year-old feeling when a paper came across my desk last week that was just published online in Conservation Biology, entitled Understanding conservationists’ perspectives on the new conservation debate by George Holmes, Chris Sandbrook and Janet Fisher. Read the rest of this entry »





Inexorable rise of human population pressures in Africa

31 08 2016
© Nick Brandt

© Nick Brandt

I’ve been a bit mad preparing for an upcoming conference, so I haven’t had a lot of time lately to blog about interesting developments in the conservation world. However, it struck me today that my preparations provide ideal material for a post about the future of Africa’s biodiversity.

I’ve been lucky enough to be invited to the University of Pretoria Mammal Research Unit‘s 50th Anniversary Celebration conference to be held from 12-16 September this year in Kruger National Park. Not only will this be my first time to Africa (I know — it has taken me far too long), the conference will itself be in one of the world’s best-known protected areas.

While decidedly fortunate to be invited, I am a bit intimidated by the line-up of big brains that will be attending, and of the fact that I know next to bugger all about African mammals (in a conservation science sense, of course). Still, apparently my insight as an outsider and ‘global’ thinker might be useful, so I’ve been hard at it the last few weeks planning my talk and doing some rather interesting analyses. I want to share some of these with you now beforehand, although I won’t likely give away the big prize until after I return to Australia.

I’ve been asked to talk about human population pressures on (southern) African mammal species, which might seem simple enough until you start to delve into the complexities of just how human populations affect wildlife. It’s simply from the perspective that human changes to the environment (e.g., deforestation, agricultural expansion, hunting, climate change, etc.) do cause species to dwindle and become extinct faster than they otherwise would (hence the entire field of conservation science). However, it’s another thing entirely to attempt to predict what might happen decades or centuries down the track. Read the rest of this entry »





Cartoon guide to biodiversity loss XXXVIII

25 08 2016

Another six biodiversity cartoons for your midday chuckle & groan. There’s even one in there that takes the mickey out of some of my own research (see if you can figure out which one). See full stock of previous ‘Cartoon guide to biodiversity loss’ compendia here.

Read the rest of this entry »





Rich and stable communities most vulnerable to change

16 08 2016

networkI’ve just read an interesting new study that was sent to me by the lead author, Giovanni Strona. Published the other day in Nature Communications, Strona & Lafferty’s article entitled Environmental change makes robust ecological networks fragile describes how ecological communities (≈ networks) become more susceptible to rapid environmental changes depending on how long they’ve had to evolve and develop under stable conditions.

Using the Avida Digital Evolution Platform (a free, open-source scientific software platform for doing virtual experiments with self-replicating and evolving computer programs), they programmed evolving host-parasite pairs in a virtual community to examine how co-extinction rate (i.e., extinctions arising in dependent species — in this case, parasites living off of hosts) varied as a function of the complexity of the interactions between species.

Starting from a single ancestor digital organism, the authors let evolve several artificial life communities for hundred thousands generation under different, stable environmental settings. Such communities included both free-living digital organisms and ‘parasite’ programs capable of stealing their hosts’ memory. Throughout generations, both hosts and parasites diversified, and their interactions became more complex. Read the rest of this entry »





Keeping India’s forests

9 08 2016

I’ve just returned from a short trip to the National Centre for Biological Sciences (NCBS) in Bangalore, Karnataka, one of India’s elite biological research institutes.

Panorama of a forested landscape (Savandurga monolith in the background) just south of Bangalore, Karnataka (photo: CJA Bradshaw)

Panorama of a forested landscape (Savandurga monolith in the background) just south of Bangalore, Karnataka (photo: CJA Bradshaw)

I was invited to give a series of seminars (you can see the titles here), and hopefully establish some new collaborations. My wonderful hosts, Deepa Agashe & Jayashree Ratnam, made sure I was busy meeting nearly everyone I could in ecology and evolution, and I’m happy to say that collaborations have begun. I also think NCBS will be a wonderful conduit for future students coming to Australia.

It was my first time visiting India1, and I admit that I had many preconceptions about the country that were probably unfounded. Don’t get me wrong — many of them were spot on, such as the glorious food (I particularly liked the southern India cuisine of dhosa, iddly & the various fruit-flavoured semolina concoctions), the insanity of urban traffic, the juxtaposition of extreme wealth and extreme poverty, and the politeness of Indian society (Indians have to be some of the politest people on the planet).

But where I probably was most at fault of making incorrect assumptions was regarding the state of India’s natural ecosystems, and in particular its native forests and grasslands. Read the rest of this entry »





Journal ranks 2015

26 07 2016

graduate_barsBack in February I wrote about our new bibliometric paper describing a new way to rank journals, which I still contend is a fairer representation of relative citation-based rankings. Given that the technique requires ISI, Google Scholar and Scopus data to calculate the composite ranks, I had to wait for the last straggler (Google) to publish the 2015 values before I could present this year’s rankings to you. Google has finally done that.

So in what has become a bit of an annual tradition, I’m publishing the ranks of a mixed list of ecology, conservation and multidisciplinary disciplines that probably cover most of the journals you might be interested in comparing. Like for last year, I make no claims that this list is comprehensive or representative. For previous lists based on ISI Impact Factors (except 2014), see the following links (2008, 2009, 2010, 2011, 2012, 2013).

So here are the following rankings of (i) 84 ecology, conservation and multidisciplinary journals, and a subset of (ii) 42 ecology journals, (iii) 21 conservation journals, and (iv) 12 marine and freshwater journals. Read the rest of this entry »





More things stay the same, more we retrogress

20 07 2016

obrazek_1idiommmmsmmWithin six months of Abbott and the Coalition seizing power in the 2013 Australian election, decades—if not centuries—of environmental damage and retrograde policies unfolded. But this was no run-of-the-mill incompetence and neglect by government—this was an all-out attack on anything with the merest whiff of environmental protection. The travesty is well-documented, from infamously axing both the carbon-pricing scheme and climate commission, eradicating Labor’s 80% emissions-reduction target by 2050, diluting the Renewable Energy Target, refusing to commit to enforcing the Illegal Logging Prohibition Act (fortunately, this is now law), defunding the only independent legal entity available to limit environmentally destructive development (Environmental Defenders Office), to even attempting to remove the rights of environmental groups to challenge development proposals (thankfully, that failed).

The Coalition’s backward and ineffectual climate change-mitigation policies alone are evidence enough for long-term damage, but their war on the environment in general means that even the future election of a more environmentally responsible government will not undo the damage quickly, if at all. As a result of these and other nearsighted policies, Australia remains one of the highest per-capita greenhouse-gas emitters on the planet, has one of the highest per-capita water uses of any nation, leads the world in mammal extinctions, continues to deforest its already forest-poor landscape, and is a society utterly unprepared to deal with the future challenges of a degraded planet.
Read the rest of this entry »





Seeing the wood for the trees

11 07 2016
The Forest Synopsis: Photo of the Anamalai Tiger Reserve, India, by Claire Wordley

The Forest Synopsis: Photo of the Anamalai Tiger Reserve, India, by Claire Wordley

From the towering kapoks of South America to the sprawling banyans of South Asia, from misty cloud forests to ice-covered pines, forests are some of the most diverse and important ecosystems on Earth. However, as conservationists and foresters try to manage, conserve and restore forests across the world, they often rely on scanty and scattered information to inform their decisions, or indeed, no information at all. This could all change.

This week sees the launch of the Forest Synopsis from Conservation Evidence, a free resource collating global scientific evidence on a wide range of conservation-related actions. These aim to include all interventions that conservationists and foresters are likely to use, such as changing fire regimes, legally protecting forests or encouraging seed-dispersing birds into degraded forests.

Making conservation work

“We hear a lot about how important it is to do evidence-based conservation”, says Professor Bill Sutherland at the University of Cambridge, UK, “but in reality getting a handle on what works is not easy. That’s why we set up Conservation Evidence, to break down the barriers between conservationists and the scientific evidence that they need to do their jobs.” Read the rest of this entry »





George Hubert Wilkins — Australia’s first whitefella conservationist?

6 07 2016

As many of you know, I have held the ‘Sir Hubert Wilkins Chair of Climate Change’ at the University of Adelaide since January 2015. My colleague and friend, Barry Brook, was the foundation Chair-holder from 2006-2014.

Initially set up by Government of South Australia to “… advise government, industry, and the community on how to tackle climate change …”, it now is only a titular position based at the University. While I certainly try to live up to the aims of the Chair, it’s even more difficult to live up to the namesake himself — Sir George Hubert Wilkins.

Given I’ve held the position now for over a year and half, I’ve had plenty of time to read about this legendary South Australian (I do choose my words carefully here). Despite most Australians having never heard of the man, it is my opinion that he should be as well known in this country as other whitefella explorers such as Douglas Mawson, Matthew Flinders, Robert Burke, William Wills, and Charles Sturt.

Sadly, he is not well-known, for a litany of possible reasons ranging from spending so much time out of Australia, never having a formal qualification in many of the skills in which he excelled (e.g., geography, meteorology, aviation, engineering, cinematography, biology, etc.), disrespect from other contemporary Australian explorers, and some rather bizarre behaviour later in his career. The list of this man’s achievements is staggering, as was his ability to thumb his nose at death (who, I might add, tried her hardest to escort him off this mortal coil many times well before a heart attack claimed him at the age of 70).

Many books have been written about Wilkins, but as I slowly make my way through some of the better-written tomes, one unsung aspect of his career has struck a deep chord within me — it turns out that Wilkins was also a extremely concerned biodiversity conservationist. Read the rest of this entry »





Subconsciously sexist?

29 06 2016

2000px-Igualtat_de_sexes.svgIt was with some consternation that I processed some recent second-hand scuttlebutt about my publishing history with respect to gender balance. I’ve always considered myself non-sexist when it comes to working with my colleagues, but as a white, middle-aged male, I’m willing to admit that perhaps subconsciously I’ve been promoting gender inequalities in science without realising that I’m doing it. As a father of a daughter, I also want to make sure the world in which she grows up isn’t as difficult as it has been for women of previous generations.

It is still an unfortunate fact that the ideal of a 50–50 gender balance in the biological sciences is far from becoming a reality; indeed, women have to be about 2.2-2.5 times more productive than their male counterparts to be as successful in securing financial support to do their work.

In fact, a 1993 study of ecologists attributed the lower (but happily, increasing) productivity and dwindling representation of women with career stage to such institutionalised injustices as: less satisfactory relationships with PhD advisors, difficulty in finding suitable mentors, lack of institutional empowerment, greater family responsibilities, lower salaries, lower job security, and lower evaluation of personal success. A follow-up study in 2012 suggested that the gap was narrowing in many of these components, but it was still far from equal. For a more comprehensive discussion of the complexity of the issues in science (see here), and in ecology in particular, see here.

Others have more recently reported no evidence for a gender effect in paper acceptance rates (Biological Conservation), and no difference in the level of perceived expertise between men and women (in long-term environmental or ecological research at 60 protected areas stratified across forests of the Asia-Pacific, African and American tropics).

Read the rest of this entry »





Buying time

27 06 2016

farmOriginally published in the Otago Daily Times by Tom McKinlay

If we don’t act soon, the world we leave our children will be in a sorry state indeed, leading Australian scientist Prof Corey Bradshaw tells Tom McKinlay.

Prof Corey Bradshaw’s 9-year-old daughter lives what sounds an idyllic existence. On their small farm outside Adelaide in South Australia, she has her chickens and her dogs and her cats, her goats and her sheep.

She’s an only child, but is not short of attention from adults and reads voraciously.

She has big plans; there are at least 25 careers she likes the look of, that she’ll undertake simultaneously: farmer, wildlife rescuer, self-sufficient bush dweller – feeding herself by shooting arrows at fish – scientist and more.

She is optimistic about the future. As she should be. A 9-year-old girl living in Australia in 2016 should regard the sky as no limit at all.

All this I learn from her father, ecologist Prof Bradshaw, who talks of his daughter with an enthusiasm unbounded.

It is fair to assume she has picked up some of her interest in the natural world from him.

He holds the Sir Hubert Wilkins Chair of Climate Change in the School of Biological Sciences at the University of Adelaide.

And the ecologist, conservation biologist and systems modeller – with a University of Otago degree – has shared a great deal of his work with his daughter.

“She’s very much a farm kid, but because of who I am she gets to hear a lot about animal and plant systems around the world, and she’s travelled a lot with me and she’s a complete fanatic of David Attenborough,” the professor says.

So far, still so idyllic. But Prof Bradshaw’s work means he is at the forefront of alerting the world to what is not right with it.

Pollution, climate change, habitat loss, extinction.

His daughter has travelled with him to see species that might not be with us by the time she grows up.

“She’s hyper-aware of extinctions, in particular, and how climate change is contributing to that,” Prof Bradshaw says.

“I don’t pull any punches with her.”

In fact, he made her cry when she was 5 explaining climate change. She hasn’t needed to travel to know the pot is on the boil. Fires have forced the family to flee its South Australian property several times, not just at the height of summer.

One of the worst fires in the region struck in May a couple of years back.

“We were on the doorstep of winter and we had one of our worst fires in 20 years.”

So even without a scientist in the family, there are certain unavoidable truths for a child growing up in 21st-century Australia.

Prof Bradshaw is coming to Dunedin next month as part of the New Zealand International Science Festival to talk on climate change, looking at it from his daughter’s perspective. Read the rest of this entry »





What immigration means for Australia’s climate-change policies

12 06 2016

After dipping my foot into the murky waters of human population demography a few years ago, I’m a little surprised that I find myself here again. But this time I’m not examining what the future of the global human population might be and what it could mean for our environment; instead, I’m focussing on Australia’s population future and its implications for our greenhouse-gas emissions trajectories.

Just published in Asia and the Pacific Policy Forum1, my paper with long-time co-author Barry Brook is entitled Implications of Australia’s population policy for future greenhouse gas emissions targets. It deals with the sticky question of just how many people Australia can ‘afford’ to house. By ‘afford’ I mean several things, but most specifically in the context of this paper is by how much we need to reduce our per capita emissions to achieve future reduction targets under various immigration-rate scenarios.

In many ways Australia’s population is typical of other developed nations in that its intrinsic fertility (1.78 children/woman) is below replacement (which is itself ~ 2.1 children/female). Yet Australia’s population grew nearly twice (1.88×) as large from 1971 to 2014. It doesn’t take a genius to figure out that most of our population growth is due to net immigration.

In fact, between 2006 and 2014, Australia welcomed a net of 215,000 new people per year (this means that of all the permanent immigrants and emigrants, a ‘net’ of approximately 215,000 stayed each year), which represents about 1% of our total population size (that latter most likely just ticked over 24 million). Read the rest of this entry »