In conversation with Current Conservation

30 11 2016

bradshaw-tinkering-with-warIn August I had the pleasure of visiting the National Centre for Biological Sciences in Bengaluru, India, and while there I was interviewed by Hari Sridhar of Current Conservation. I admit that I haven’t always fully appreciated the excellent conservation reporting done by Current Conservation, and now after having been interviewed by them, I’m becoming more aware of their value (and not just because I appear in their latest issue). I really encourage readers to check it out.

In a paper published in the Proceedings of the National Academy of Sciences USA in 2014, Corey Bradshaw and Barry Brook argued that, given the current momentum of human population growth, no demographic “quick fixes” will be enough to change its trajectory in the near future. Therefore, environmental policy will be served better by prioritising measures such as technological and social innovation and reductions in consumption, while treating population reduction as a long-term goal. On his recent visit to Bengaluru, I spoke to Corey Bradshaw about the genesis of this study and its implications.

Hari Sridhar: You say “our models clearly demonstrate that the current momentum of the global human population precludes any demographic “quick fixes.” If that is the case, what do you suggest should be done instead?

Corey Bradshaw: I’ll back up a little bit and give you some of the context for writing the paper, which will sort of explain the title and that particular conclusion. Often when I gave public seminars, where I would talk about some environmental problem and future predictions of its worsening, some member of the audience would stand up at the end and say: “Well, the problem is humans. There are just too many of us. So all we need to do is focus on reducing the human population and we will fix all of these other problems.” That came up so often that I began to think: “Well, how quickly could we fix the overpopulation problem?”

Being, among other things, a population dynamics modeller, I decided I could model the human population just as well to look at that question. What would it take and how long for human population to start to decline, either from interventions or catastrophes? Human demographers don’t typically consider catastrophe scenarios when they project human populations. It’s instead done under very strict policy criteria, typically under the expected status quo, with some slight variation in things like family planning and structural change, you know, things like age structure. But we decided to try out more extreme scenarios as well to address that question. So first we said “let’s just see what happens when we only adjust fertility”. We did that and the population trajectory was more or less insensitive.

Then we said “let’s see what happens if we impose mass mortality events of various types — a third world war, pandemics, nuclear warfare” — and still the population was fairly resistant, even to these big changes. What we took away from these results was this: yes, population size must be addressed and we should have started looking into this seriously, probably post World War 2 when we were just under two billion people. We need to address overpopulation, but it’s not going to be something that can be fixed suddenly or be reduced anytime in the next few decades. It’s a century-scale issue. Should we be aiming to reduce the total human population? Yes. Should we be encouraging fertility reduction and family planning? Yes. It’s just that these will have positive outcomes at the century scale. Now most of our environmental problems are not things that we can ignore for a century. They have to be dealt with now. So our argument basically was that if we can’t address the human population problem, in the sense of reducing its size quickly, then we need to turn our attention to more immediate fixes, such as addressing consumption and various environmental mitigation policies. That was our main message. But in so doing we managed to anger both sides of the ideological position on the human population debate. In saying that something must be done but it can’t be done quickly, we upset the low-growth proponents. And by saying that we should nevertheless aim for long-term population reduction, we upset the people who are utterly opposed to any sort of fertility reduction or any action on human population growth.

HS: That’s something I want to ask you about — tell us about the attention this paper got within academia and in the media.

CB: Yeah, in the academic setting it was interesting. There were only a few critiques written about the paper and they were fairly weak. As the saying goes “All models are wrong but some are useful”, but what our model said was defensible. I suppose some of the terminology and the interpretation were points of contention with some people, but by and large the scientific community was satisfied with the result. But in the media it was completely different. Almost every single journalist I talked to put a particular slant on the results. Because of those two diametrically opposite opinions, people appeared to read anything they wanted to into it. Most people in the media didn’t of course read the paper. They read the title and maybe the abstract and the odd sentence here and there, and took from that whatever their ideological position dictated. There was right-wing media, there was left-wing media, and each had its own bias. I think only a handful of interviewers seemed to grasp the concept, which I didn’t think was that difficult. It also got a lot of responses on these comment streams. I don’t read those most of the time, but there are a lot of crazy people on the internet now. I got all sorts of hate mail, and even indirect death threats. Not serious ones. Just some random person telling me I should be removed from the face of the planet, and things like that. That happens from time to time when you deal with controversial topics.

HS: In the paper, you come up with some figures for what the population will be in 2100, under different scenarios. Could you tell us how much uncertainty there was around these figures?

CB: There was probably much less uncertainty than for most other species that are modelled. Humans tend to census themselves fairly well and we have a reasonable understanding of how many of us there are right now. While demographic data like age-specific survival rates are missing from some parts of the world, generally speaking at the scale of regions it’s well-known. So in terms of measurement error, the current and even the trends in those demographic rates are robust. Some of the assumptions, such as how much longer we’ll live given future medical innovations, are somewhat uncertain. But as it turns out, we are living so long now that even slight adjustments to longevity don’t make much difference in the long-term to total population size. And even large assumptions about, say, juvenile mortality, don’t make a huge difference because for a long-lived mammal the most important parameter that modifies population growth generally is the survival of breeding females. And breeding-age woman around the world tend to have the highest survival rates, so all the other parameters have smaller effects on population size. So while environmental variability has a large effect on small populations, it has a comparatively small effect on large populations. And we are a very large population. Incorporating a lot of uncertainty didn’t really make much of a difference. But the future scenarios were uncertain – will there be a war, will there be climate change reductions in food availability that will lead to higher juvenile mortality, etc.? We know little about the probability these things will occur and how important they’ll be. Read the rest of this entry »

Tips for scientists to deal with the media

21 11 2016


I regularly give science communication workshops that include tips for dealing with reporters and journalists in the mass media. Most of these tips come from my own experience, or from stories I’ve heard from close colleagues. Instead of just teaching these important lessons to a select few who get to hear about them in person, I’ve decided to write a little post listing the most important points. Most of the following has little to do with maximising the likelihood of getting an interview, but these tips should help you avoid problems should a reporter notice your important work.

Welcome to the jungle.

1. The best way to get noticed by the media is to write a press release, although this is no guarantee in itself that anyone will pay attention. A good rule of thumb is to write a release for nearly every peer-reviewed article you publish, even if you think no one will be that interested. You’d be surprised how seemingly innocuous and run-of-the-mill papers can go viral if the press release is well-written. On that latter point, engage closely with your institution’s media office, and help them write the release by, for example, sending them a link to the lucid blog post you wrote about your own paper.

2. You can maximise the probability of uptake of your press release if you foster good working relationships with journalists. If you’ve ever had positive interactions with some before, keep the names on record and send a pre-release version of the article and the press release itself before the main event. Every journalist loves a scoop.

3. Register on expert media sites so that journalists can find you (e.g., like Scimex, Expert Guide, Ocean Expert, etc.). Most countries have such things.

4. If a journalist contacts you, make sure you respond immediately. Often even 30 minutes is too long before they seek opinions from some other scientist. If you are travelling, make sure you have an emergency contact auto-responder designed specifically for deadline-enslaved journalists.

Remember, you're smarter than they are (© Monty Python)

Remember, you’re smarter than they are (© Monty Python)

5. Once you do manage to gain an interview, whether it is live radio, recorded television or just as a chat for a newspaper article, avoid jargon like the plague. And make sure you test your language on a non-expert — what’s jargon to a non-specialist might not appear to be jargon at all to you. This often comes with experience, but at the very least try to avoid big, technical-sounding words (they do not make you sound more intelligent; rather, they make you sound boring and up-yourself).

6. Still on the issue of language, use short, punchy answers, analogies and a little humour. Try to relax (again, this comes with experience) by remembering that you know your shit more than 99.99% of the people that will be listening to you.

Read the rest of this entry »

Boreal forest on the edge of a climate-change tipping point

15 11 2016

As some know, I dabble a bit in the carbon affairs of the boreal zone, and so when writer Christine Ottery interviewed me about the topic, I felt compelled to reproduce her article here (originally published on EnergyDesk).

A view of the Waswanipi-Broadback Forest in the Abitibi region of Northern Quebec, one of the last remaining intact Boreal Forests in the province (source: EnergyDesk).

A view of the Waswanipi-Broadback forest in the Abitibi region of northern Quebec, one of the last remaining intact boreal forests in the Canadian province (source: EnergyDesk).

The boreal forest encircles the Earth around and just below the Arctic Circle like a big carbon-storing hug. It can mostly be found covering large swathes of Russia, Canada and Alaska, and some Scandinavian countries.

In fact, the boreal – sometimes called by its Russian name ‘taiga’ or ‘Great Northern Forest’ – is perhaps the biggest terrestrial carbon store in the world.

So it’s important to protect in a world where we’re aiming for 1.5 or – at worst – under two degrees celsius of global warming.

“Our capacity to limit average global warming to less than 2 degrees is already highly improbable, so every possible mechanism to reduce emissions must be employed as early as possible. Maintaining and recovering our forests is part of that solution,” Professor Corey Bradshaw, a leading researcher into boreal forests based at the University of Adelaide, told Energydesk.

It’s not that tropical rainforests aren’t important, but recent research led by Bradshaw published in Global and Planetary Change shows that that there is more carbon held in the boreal forests than previously realised.

But there’s a problem. Read the rest of this entry »

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 »