[PERN Cyberseminar] Population growth as a driver of displacement

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Jane O'Sullivan

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May 16, 2021, 7:08:34 PM5/16/21
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Hello to the panelists and participants, 

Thank you to all for an interesting discussion. However, one area seems oddly neglected in this discussion. Do demographers have nothing to say about the role of population pressure in causing the circumstances from which people flee?

Jalal said in the webinar that demographic drivers act in concert with other drivers. This seemed to be a way of dismissing further examination of demographic drivers. Yet it would be more accurate and enlightening to say that other drivers act in concert with demographic pressure. Can any of them be properly understood without referencing the underlying effects of population growth?

Clearly there are natural disasters that are independent of demography, but normally they only displace people locally and temporarily. Even there, there is also an influence of demographic pressure placing more people in harm’s way – onto floodplains or beach fronts or steep slopes which people avoided in the past due to their hazards, but which now support dwellings because there is nowhere else to expand into.

Can anyone name any instances where long-term displacement of people has not involved an underlying stress of overpopulation?

Is it reasonable to imagine that people displaced from a conflict or famine resulting from overpopulation can ever go home without recreating the crisis? Their numbers would be replaced within a few years.

Migration literature, particularly under the “new economics of labour migration” (NELM) theory, tends to ignore population growth as a driver of migration. Analyses typically present the decision of a household to send migrants as one of income diversification and self-insurance. For example, Taylor (2002) https://doi.org/10.1111/1468-2435.00066 sees rural-urban migration as a phenomenon driven by GDP growth and its implicit link with economic diversification, and suggests that constraints on local production and livelihoods are due to “market failures” such as inadequate market access, finance and insurance systems.  The presumption is that, without climate change or other exogenous factors undermining livelihoods, the economic situation would be stable or gradually improving due to development, and migration offers a means to enhance development. But nothing is stable where populations are growing. The climate migration literature does not discuss the common reality that the alternative to out-migration from rural areas is an ever-dwindling allocation of natural resources per household (arable land, water, or access to common forest, pasture or fishing resources),  and the inevitable degradation of those resources due to overuse.  Equally absent is any recognition that such subdivisions and degradations over the past two generations have contributed to the impoverishment of households, and their vulnerability to adverse weather events and their proclivity to use violence to defend their resources or to capture someone else’s.

Have demographers got nothing to contribute to an understanding of population pressure?

Jane O'Sullivan


Richard Seager

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May 16, 2021, 7:50:08 PM5/16/21
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Can anyone name any instances where long-term displacement of people has not involved an underlying stress of overpopulation?

The Dust Bowl of the 1930s in the USA?


Is it reasonable to imagine that people displaced from a conflict or famine resulting from overpopulation can ever go home without recreating the crisis? Their numbers would be replaced within a few years.

Migration literature, particularly under the “new economics of labour migration” (NELM) theory, tends to ignore population growth as a driver of migration. Analyses typically present the decision of a household to send migrants as one of income diversification and self-insurance. For example, Taylor (2002) https://doi.org/10.1111/1468-2435.00066 sees rural-urban migration as a phenomenon driven by GDP growth and its implicit link with economic diversification, and suggests that constraints on local production and livelihoods are due to “market failures” such as inadequate market access, finance and insurance systems.  The presumption is that, without climate change or other exogenous factors undermining livelihoods, the economic situation would be stable or gradually improving due to development, and migration offers a means to enhance development. But nothing is stable where populations are growing. The climate migration literature does not discuss the common reality that the alternative to out-migration from rural areas is an ever-dwindling allocation of natural resources per household (arable land, water, or access to common forest, pasture or fishing resources),  and the inevitable degradation of those resources due to overuse.  Equally absent is any recognition that such subdivisions and degradations over the past two generations have contributed to the impoverishment of households, and their vulnerability to adverse weather events and their proclivity to use violence to defend their resources or to capture someone else’s.

Have demographers got nothing to contribute to an understanding of population pressure?

Jane O'Sullivan


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Jane O'Sullivan

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May 16, 2021, 10:10:54 PM5/16/21
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Thank you, Richard. The American 'dust bowl' is an interesting suggestion. 

It raises the issue of defining overpopulation. It is typically defined in relation to the carrying capacity of the resource base, and characterised by degradation of that resource base to the extent that feedbacks constrain further population growth. 

It should be noted that overpopulation is not defined with reference to a theoretical optimum set of behaviours, institutions and technologies through which the carrying capacity could be sustainably maximised. It merely refers to what actually happens. Thus, we can get out of a situation of overpopulation either by reducing the population of the area, or by changing our management of the resource base in order to raise its carrying capacity for humans. But if it is possible to do the latter, that is not proof that we never were overpopulated, it is a (belated) remedy for the overpopulation, and one that will be ephemeral unless further population growth is avoided.

In the case of the American 'dust bowl', a very rapid (in ecological terms) escalation of human activities that degraded the resource base led to the demise of those human livelihoods. A classic case of overpopulation!

Let's not forget that these people arrived from an overpopulated Europe, whereby working a small plot of land intensively for a bare living seemed like an attractive opportunity compared with what they left behind. This background and their unfamiliarity with the local soils and climate encouraged them to take on farms that were too small to be sustainable.

It is true that technological development has led to agriculture becoming less labour-intensive, and rural landscapes in developed countries depopulating. But this should lead to an increase in off-farm livelihood opportunities (unless the agricultural profits are siphoned off by a multinational corporation), so that urbanisation is driven by pull factors rather than push factors, and can't be called displacement. The urbanisation we are seeing in sub-Saharan Africa is driven by push-factors and has not depopulated the countryside, yet it can be seen as displacement. Note that projected rural-urban migration in these regions is vastly greater than the projected displacement likely to be caused by climate change, again attesting that population growth is the dominant displacer.

Can anyone offer any other examples?

Jane

From: Richard Seager <sea...@ldeo.columbia.edu>
Sent: 17 May 2021 09:48
To: Jane O'Sullivan <j.osu...@uq.edu.au>
Cc: Population-Environment Research Network (PERN) cyberseminars <pernse...@ciesin.columbia.edu>
Subject: Re: [PERN Cyberseminar] Population growth as a driver of displacement
 

Richard Seager

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May 16, 2021, 10:16:06 PM5/16/21
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Hi Jane,

I think that saying the cause of the permanent migration out of the Dust Bowl was due to over-population would miss the multiple and other important drivers.

It is true that farmers hoped they would be able to make a living on quite small plots of land when they settled there in the late 19th to early 20th century.
This worked quite well in the 1920s when the climate was reasonably wet but was not going to work well in the 1930s when drought struck.
So the climate variation is a distant cause of the migration.  

Yes, the farming methods being used - typical of the humid eastern US - were not appropriate for the Plains and made the situation worse - soil erosion and dust storms.  The dust storms - we believe based on climate model simulations - made the drought worse.
So farming technology and practice and lack of knowledge of vegetation-dust-atmosphere interactions are also a cause of the migration.

Controlling soil erosion and dust storms is hard when the spatial scale of the erosion exceeds that of the farm size.  Your dust lands on someone else's farm and your crops are inundated by some other farmers dust.  Meanwhile if drought reduces yield the incentive is to plant a larger area and reduce fallowed land and shelter belts. That leads to more erosion.
Hence the size of farm operations and economic structure of the economy are a cause of the migration.  

The Soil Conservation Service worked much of this out in the 1930s and were able to encourage soil conservation practices that reduced erosion even before the drought ended.  But by that time the migration had happened.

The out-migration led to others buying up land and an increase in farm size - with more incentive and economy-of-scale to practice conservation.  
Steinbeck actually emphasizes the economic inequality more than the drought as a cause of migration - a fictionalized version of what was likely happening.

The Dust Bowl also led to the beginning of Federal farm supports.

Also in the 1950s automobile engines were converted to power wind pumps and the era of groundwater irrigation began.  
Due to changes in farm operations, the regional economy, conservation, irrigation, Federal farm support, nothing like the Dust Bowl has happened again.  

Since then rural population in the Plains over the 10thC steadied at a level lower than the 1920s but overall population increased.  
I would not want to reduce this complex story of human-environment interactions to one of over-population.

Cheers,
Richard

Richard Seager
Palisades Geophysical Institute/Lamont Research Professor
Lamont Doherty Earth Observatory of Columbia University
61 Route 9W, Palisades, NY 10964
sea...@ldeo.columbia.edu
Tel: 845-365-8743
“Who wants it all a bed of roses anyway?”, Lal Waterson, Memories.



Ilan Kelman

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May 17, 2021, 6:50:37 AM5/17/21
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Thank you for this helpful discussion and the comments. Some contributions to directly address a few of the points:

1. I would suggest caution on the assumption that people migrated from Europe to North America solely because of overpopulation. Part of the reason that people had small plots of land and had trouble eking out an existence on them was inequities and governance leading to poverty, marginalisation, and oppression.

2. Demography is discussed extensively in relation to these topics, e.g. https://jpopsus.org/full_articles/disaster-vulnerability-by-demographics/ and this has long been the case, e.g. https://doi.org/10.2307/2089239 and https://www.tandfonline.com/doi/abs/10.1080/00324728.1971.10405783 keeping in mind that the fields of the two latter publications have moved on extensively from what these papers relate.

3. Disaster science prefers to avoid the phrase "natural disaster" since disasters are not natural, but are caused by society creating vulnerabilities, for which population numbers are one input, but far from the only input:
4. Examples of long-term displacement of people which has not involved an underlying stress of overpopulation are extensive. One set of examples is island volcanic eruptions forcing long-term displacement, e.g. Niua Fo’ou in Tonga in 1946, Tristan da Cunha in the South Atlantic in 1961 with return in 1963, Pinatubo in the Philippines in 1991, Manam in Papua New Guinea on-and-off since 2004, and Montserrat since 1995. In all these instances, population density and numbers were not exceptionally high for the land area and resource productivity, but living in the location would be fatal due to the volcano. Another set of examples is earthquakes, e.g. following Christchurch 2011 and the earthquake-induced tsunamis on 2004 around the Indian Ocean and in Japan in 2011. In all of these cases, many people have left the impacted areas never to turn--as also occurred with many residents of New Orleans after Hurricane Katrina in 2005.

Looking forward to continued discussion and any further thoughts on. these topics. With thanks and best wishes,

Ilan



From: Richard Seager <sea...@ldeo.columbia.edu>
Sent: May 17, 2021 03:13

Jane O'Sullivan

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May 17, 2021, 6:50:40 AM5/17/21
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Dear Richard, 

I neither "miss the multiple and important other drivers" nor "reduce this complex story of human-environment interactions to one of over-population."

I am merely saying that, if population pressure is influencing the situation, studying the multiple other drivers without referencing the population pressure will not give you a full and true understanding of the situation. 

It is not reductionist to ask that population pressure be included in analyses. It is reductionist to suggest (as you seem to be doing) that including it is to exclude everything else.

Inequality is a case in point. There are, of course, instances where inequality is due to colonial domination and racism, but the widening of inequality within societies is usually driven by a surfeit of labour bidding down wages and, in doing so, increasing profits for employers. In a tight labour market, inequality lessens (as, for example, in Europe after the Black Death). Where productivity is increasing faster than population growth, inequalty also tends to lessen (as in the developed world during the expansion of oil consumption, between WWII and the OPEC crisis in the 1970s). So it means little to say that inequality, not population pressure, contributed to the displacement during the Dust Bowl. The two are like two sides of a coin. 

You said, "if drought reduces yield the incentive is to plant a larger area and reduce fallowed land and shelter belts. That leads to more erosion." You could equally have observed that "if population pressure reduces yield per person the incentive is to plant a larger area and reduce fallowed land and shelter belts. That leads to more erosion." The latter is far more widely applicable. That dust-bowl effect that you mentioned, where too much land clearing reduces rainfall, is as yet the more important cause of rainfall deficits in tropical Africa than is climate change. 

All habitats have good years and bad years. Carrying capacity is defined by the bad years. The settlement of the American mid-west was sufficiently rapid that people didn't know what to expect in a bad cycle. The farmers in the Punjab have got used to using groundwater to compensate for rainfall deficits, allowing population density to increase. But when the groundwater runs out (as is rapidly happening), this is not a climate change issue but an overpopulation issue. 

I am not trying to diminish the role of droughts and climate change at all. I am merely wondering why a phenomenon that is reducing per capita food production in sub-Saharan Africa, Western and Southern Asia much faster and much further than projected climate change, and underlies every violent conflict in those regions, is completely unmentioned.

I could pre-empt the answer to that question, as I know that many people think there is no humane action that can be taken to limit population growth, so anyone who puts a focus on population growth is advocating some sort of draconian population control measures. That is part of the vicious cycle of the population taboo - because we don't talk about it, people are ignorant of the many great examples of voluntary family planning programs that empowered women and communities, and enabled transformative economic development. Because of the taboo, people believe the myths that populations will stabilize if we just work on ending poverty and educating girls. Those indirect drivers of fertility are helpful but very weak compared with family planning provision and promotion. No instance of rapid fertility transition has happened without policies aimed at making it happen. But that doesn't mean that they included coercive limits on family size or forced sterilisations. In some cases they did, and that was extremely regrettable, not only for the human rights violations but because coercion undermines family planning uptake.

For a short presentation on the myths, see https://www.youtube.com/watch?v=7VJSWI5mPPI&t=110s

Jane 




From: Richard Seager <sea...@ldeo.columbia.edu>
Sent: 17 May 2021 12:13

Richard Seager

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May 17, 2021, 8:34:59 AM5/17/21
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Hi Jane,
I don’t want to get into a long back and forth on this but what is interesting is how people can look at exactly the same problem and agree on most of the issues and still discuss it in conflicting and incompatible ways!
But back to the climate science for a while ….
too much land clearing reduces rainfall, is as yet the more important cause of rainfall deficits in tropical Africa than is climate change. 
Most climate scientists, myself included, dispute that there is evidence for rainfall changes in Africa induced by land surface modification being of more importance than those induced by sea surface temperature variations or changes in radiative forcing.  The Dust Bowl in the US was rather unique in this case since human-induced land modification does seem to have impacted the climate system but there we were talking about use of powerful machinery backed operating within a global market - the ability to transform the land was immense.  The idea that ag in Africa leads to desertification - which was alas proposed by one of the world’s great meteorologist Jules Charney in the 1970s - has fallen out of favor in the climate community as the role of the oceans and radiative forcing (greenhouse gases, aerosols) has become clearer with the advance of climate modeling.   However this desertification narrative has unfortunately remained prevalent in development circles for some reason.

Cheers,
Richard

Richard Seager
Palisades Geophysical Institute/Lamont Research Professor
Lamont Doherty Earth Observatory of Columbia University
61 Route 9W, Palisades, NY 10964
sea...@ldeo.columbia.edu
Tel: 845-365-8743
“Who wants it all a bed of roses anyway?”, Lal Waterson, Memories.



Richard Seager

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May 17, 2021, 8:35:07 AM5/17/21
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Hi Jane,
By the way I fully agree with the need for education and empowerment of women and girls to enable voluntary population control (and so much more) - absolutely!  
In this regard I note that the fabulous Project Drawdown on climate mitigation strategies gave great prominence to educating girls this as a very powerful way to reduce GHG emissions:
In my print book it was something like the second most effective single strategy. So population growth is discussed in the climate mitigation world.  (One of the other most effective ones was phasing out high GHG warming potential HFSc from refrigeration which the world is now doing - yay progress!)
Cheers,
Richard

Richard Seager
Palisades Geophysical Institute/Lamont Research Professor
Lamont Doherty Earth Observatory of Columbia University
61 Route 9W, Palisades, NY 10964
sea...@ldeo.columbia.edu
Tel: 845-365-8743
“Who wants it all a bed of roses anyway?”, Lal Waterson, Memories.



Tom Dietz

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May 17, 2021, 9:34:25 AM5/17/21
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There is a fairly substantial literature that can be found by entering the term STIRPAT into Google Scholar that assumes that there are multiple interacting influences on anthropogenic environmental stress.  In this context "interacting" means that the effect of population depends on the level of affluence, patterns of consumption, etc. and that the effect of affluence depends on the other factors and so on.  This literature then uses empirical data to estimate the effects of each factor (essentially the elasticity) for particular environmental stresses using comparisons across nations, states, provinces, etc.  A major focus of this approach is the influence of inequality, but the work also examines many aspects of political economy, women's empowerment, etc.  Two recent reviews at least touch on this literature:
Dietz, Thomas, Rachael L Shwom and Cameron T Whitley. 2020. "Climate Change and Society." Annual Review of Sociology 46:135-58.
Jorgenson, Andrew K, Shirley Fiske, Klaus Hubacek, Jia Li, Tom McGovern, Torben Rick, Juliet B Schor, William Solecki, Richard York and Ariela Zycherman. 2019. "Social Science Perspectives on Drivers of and Responses to Global Climate Change." Wiley Interdisciplinary Reviews: Climate Change 10(1):e554.

Best,
Tom



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Jane O'Sullivan

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May 17, 2021, 10:21:53 AM5/17/21
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Hi Richard, 
Thanks for the constructive exchange.
Regarding the impact of vegetation clearing on rainfall, I am not a climatologist and I don't claim to have done an exhaustive review of the literature on this, but my sources were more recent than the 1970s:

Lawrence, D., & Vandecar, K. (2015) Effects of Tropical Deforestation on Climate and Agriculture. Nature Climate Change 5 (1): 27-36. https://doi.org/10.1038/NCLIMATE2430

Ellison, D., Morris, C.E., Locatelli, B., et al. (2017) Trees, Forests and Water: Cool Insights for a Hot World. Global Environmental Change 43 (March): 51–61. https://doi.org/10.1016/j.gloenvcha.2017.01.002

Pearce, F. (2018) Rivers in the Sky: How Deforestation Is Affecting Global Water Cycles. Yale Environment 360, 24 July 2018. https://e360.yale.edu/features/how-deforestation-affecting-global-water-cycles-climate-change

Mahmood, R., Pielke, R.A.Sr., Hubbard, K.G., et al. (2014) Land cover changes and their biogeophysical effects on climate. International Journal of Climatology 34(4), 929-953. https://doi.org/10.1002/joc.3736

Zeng, N., Neelin, J.D., Lau, K.M. & Tucker, C.J. (1999) Enhancement of interdecadal climate variability in the Sahel by vegetation interaction. Science 286:1537–1540. https://doi.org/10.1126/science.286.5444.1537

Zheng, X. & Eltahir, E. A. B. (1998) The Role of Vegetation in the Dynamics of West African Monsoons. Journal of Climate 11(8): 2078-2096. https://doi.org/10.1175/1520-0442(1998)011<2078:TROVIT>2.0.CO;2

As for Project Drawdown, yes, they were the exception to the rule in including an estimate of emissions avoidance by lowering population growth. But it is sad that this is as good as it gets. Their analysis is exceedingly crude and their 2020 update downplayed any mention of population growth - I wrote a critique here: 
https://overpopulation-project.com/drawdown-a-review-of-the-review/

I am, however, encouraged by the calibre of people they have since enlisted to work on this solution. 

My problem is that they are missing the most effective actions, by buying into the myth that "education and empowerment of women and girls to enable voluntary population control" is the most effective and just approach. What is implied is that any intervention that identifies population growth as a problem and openly seeks to lower family size preferences is inevitably coercive/racist/undermining women's rights. This myth has been well used by the opponents of women's reproductive rights (look no further than the Holy See) to make a public enemy of the very people who did most good for women's rights. Please don't take this as a personal rebuttal - you and 99% of people who think they have an informed opinion on the subject have fallen for this. Yet it isn't true that girls' education is the key to rapid fertility decline. Voluntary family planning programs (providing access and promotion) have enhanced girls' access to education probably more than efforts for girls' education have enhanced family planning uptake. Unless there is high-profile communication of the benefits to be had through birth control, cultural change is slow.

I fear that scientific communities - and, disappointingly, most demographers - are self-censoring to ignore the role of population growth, through fear of invoking (or being accused of invoking) China-style one-child policies and forced sterilizations. By self-censoring, we are completely missing the only real solution to mounting crises of human ecology, and elevating policies that have no hope of resolving problems in the long term. That is not an ethical approach. It is abetting major humanitarian crises.

Thanks again for your exchange,

Jane



From: Richard Seager <sea...@ldeo.columbia.edu>
Sent: 17 May 2021 22:21

Jane O'Sullivan

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May 17, 2021, 10:33:00 AM5/17/21
to Tom Dietz, Ilan Kelman, pernse...@ciesin.columbia.edu
Thank you very much for those references, Tom. 

Re "the effect of population depends on the level of affluence, patterns of consumption, etc", 
do you think it would be accurate to say that the effect of population growth ON CLIMATE CHANGE depends largely on the level of affluence, but the effect of population growth ON SECURITY depends largely on poverty?

Jane

From: Tom Dietz <tdie...@gmail.com>
Sent: 17 May 2021 23:33
To: Ilan Kelman <ilan_...@hotmail.com>
Cc: pernse...@ciesin.columbia.edu <pernse...@ciesin.columbia.edu>

Jane O'Sullivan

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May 17, 2021, 11:24:55 AM5/17/21
to Ilan Kelman, pernse...@ciesin.columbia.edu
Dear Ilan, 

Thanks very much for your insights. 

I can't help thinking that your examples of events that caused long-term displacement belie your statement that "Disaster science prefers to avoid the phrase "natural disaster" since disasters are not natural, but are caused by society creating vulnerabilities." In the case of an island obliterated by a volcano, it is hard to see how the vulnerability depended on any choice or deficiency of the society.

As examples of long-term displacements not underpinned by population pressure, they would seem to be the exceptions that prove the rule: it looks like it takes a natural event that permanently transforms the resource base to do it. 

Of course, in instances where people are suddenly displaced due to a geological or meteorological event, there will be many people who never go back because they've found opportunities elsewhere in the meantime. I'm not sure that this counts as a permanent displacement of population. I was thinking more of the situation where people are held in limbo as refugees for protracted periods of time.

Jane

From: Ilan Kelman <ilan_...@hotmail.com>
Sent: 17 May 2021 17:43
To: pernse...@ciesin.columbia.edu <pernse...@ciesin.columbia.edu>

Ilan Kelman

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May 17, 2021, 11:49:22 AM5/17/21
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Dear Jane,

Thank you for your further thoughts and responses. The sources which I provided explain exactly why the examples mentioned are not natural disasters, in particular noting that vulnerability is not only the "choice or deficiency of the society" as you state, but also choices and deficiencies of others--appearing and influencing in combination to different levels. To quote you, "you and 99% of people who think they have an informed opinion on the subject have fallen for this" assumption that such disasters are natural. As you rightly advise others, it would be helpful to please read the references in this field before jumping to assumptive and incorrect conclusions. Thank you so much! Some more on this point:

If I may, I would also be curious regarding your reply regarding the examples of long-term displacements? You asked for examples, I gave them, and you accept them. Why would it be valuable to claim that they are "exceptions that prove the rule" without providing any evidence for this statement? How many examples should I provide in order to prove that they are not exceptions?

Similarly, you write "many people who never go back because they've found opportunities elsewhere in the meantime. I'm not sure that this counts as a permanent displacement of population". "People who never go back" would seem to be the definition of "permanent displacement of population"?

As for "people are held in limbo as refugees for protracted periods of time", you have now changed your initial query from "long-term displacement" to "refugees". The examples which I gave of Tristan da Cunha and Manam were noted as being people held in limbo as displaced populations for protracted periods of time. If you would prefer examples of refugees, then feel free to do a systematic literature search and plenty will turn up--unless you would perhaps be willing to accept material and examples which we provide, rather than subsequently re-formulating the specific question to which you seek an answer? Again, how many examples would you need in order to be convinced?

Hope this helps and with best wishes, with thanks again for your contributions and looking forward to further discussion,


From: Jane O'Sullivan <j.osu...@uq.edu.au>
Sent: May 17, 2021 15:41
To: Ilan Kelman <ilan_...@hotmail.com>; pernse...@ciesin.columbia.edu <pernse...@ciesin.columbia.edu>

Alessandra Giannini

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May 17, 2021, 11:58:56 AM5/17/21
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Hello Jane and everyone, I will chime in on the topic of the impact of vegetation clearing on rainfall in Africa, adding detail to Richard’s message.

I’ll make one generic point — not all regions of the tropics are the same. Perhaps the argument (about the impact of land cover change on rainfall) has more reason to persist when applied to climatologically wet regions like the Amazon and other tropical rainforests, where a greater proportion of the moisture is recycled locally. But it is definitely not applicable in semi-arid regions, where most of the moisture is imported from the ocean, in monsoon circulations.
The Sahel, which is where all talk of desertification as we’ve known it since the mid-1970s began, is a case in point.
So, the specific point — that Richard sketched — is about the Sahel. Your references below (Zeng et al 1999; Zheng and Eltahir 1998) are, indeed, outdated!
They have been supplanted by a slew of studies that demonstrate the dominant role of the oceans first, then implicate human emissions, especially aerosols, in the patterns of oceanic change:

Giannini, A., Saravanan, R. and Chang, P., 2003. Oceanic forcing of Sahel rainfall on interannual to interdecadal time scales. Science, 302(5647), pp.1027-1030.

Bader, J. and Latif, M., 2003. The impact of decadal‐scale Indian Ocean sea surface temperature anomalies on Sahelian rainfall and the North Atlantic Oscillation. Geophysical Research Letters, 30(22).

Lu, J. and Delworth, T.L., 2005. Oceanic forcing of the late 20th century Sahel drought. Geophysical Research Letters, 32(22).

Biasutti, M. and Giannini, A., 2006. Robust Sahel drying in response to late 20th century forcings. Geophysical Research Letters, 33(11).

Ackerley, D., Booth, B.B., Knight, S.H., Highwood, E.J., Frame, D.J., Allen, M.R. and Rowell, D.P., 2011. Sensitivity of twentieth-century Sahel rainfall to sulfate aerosol and CO2 forcing. Journal of Climate, 24(19), pp.4999-5014.

Hwang, Y.T., Frierson, D.M. and Kang, S.M., 2013. Anthropogenic sulfate aerosol and the southward shift of tropical precipitation in the late 20th century. Geophysical Research Letters, 40(11), pp.2845-2850.

Giannini, A. and Kaplan, A., 2019. The role of aerosols and greenhouse gases in Sahel drought and recovery. Climatic change, 152(3), pp.449-466.

… 

The bottom line is that vegetation clearing does have an effect, as hypothesized by Charney (alas!), but it is not the only effect.
So, any and all studies that look at this single effect in isolation are bound to be partial to the conclusion.

Thank you for engaging in this truly diverse interdisciplinary exchange!

warm regards, alessandra







— 
Alessandra Giannini
Professeure des Universités / Full Professor
CERES - Géosciences - LMD, École Normale Supérieure 
24, Rue Lhomond 75231 PARIS CEDEX 05, France
Adjunct Senior research scientist, IRI/Columbia University

Jane O'Sullivan

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May 18, 2021, 6:29:34 AM5/18/21
to Alessandra Giannini, Population-Environment Research Network (PERN) cyberseminars
Hi Alessandra, 

Thanks very much for that line-up of papers. This is an interesting topic, and a potentially important influence on future displacements of people. 

However, once again, I find myself being accused of saying something is "the only effect" when what I said was that it was an effect that should be included in considerations. 

As far as I recall, the effect of land clearing on rainfall in the Sahel was predominantly attributed to clearing in the East African highlands and the Congo basin - i.e. in the humid tropics, not local clearing in the Sahel. I was first introduced to this by a side event at a UNFCCC conference, where ICRAF scientists presented their work on water recycling, mapping the movement of transpired water from Central Africa across West Africa, and presented evidence that loss of tree cover was contributing to downwind drying. This was in about 2013, I think. But I couldn't find a paper by those scientists on the subject.

It isn't obvious to me from the titles of your papers, which of them also looks at land clearing, and gives any assessment of the relative contributions of greenhouse gases/ocean temperature, aerosols and land clearing. Can you point me to any that do? If they do not, given the noise in the data you are dealing with, can you really say that vegetation change does not have a significant influence, based on studies that show that the observed change could be accounted for by aerosols and sea surface temperature?

I did look at your 2019 paper, and am somewhat heartened that you find the Sahel likely to increase its rainfall on account of climate change and a fall in aerosol load. Do you have anything to add about the likelihood of greater variability and intensity of rainfall?

Many thanks, 
Jane

From: Alessandra Giannini <ale...@iri.columbia.edu>
Sent: 18 May 2021 01:50

Alessandra Giannini

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May 18, 2021, 8:01:00 AM5/18/21
to Jane O'Sullivan, Population-Environment Research Network (PERN) cyberseminars

hello Jane, 

happy to delve into some more detail.

The point to take home about studies such as mine in 2003 is that in fact the two effects are not of comparable magnitude. The influence of the oceans dominates over that of land clearing. 
In the case of the Sahel, I can state this with confidence because a climate model with only the oceanic influence as observed is sufficient to explain the multi-decadal ups and downs of 20th century Sahel rainfall. 
The following will not fully address your point, because there were no parallel simulations available that had a prescribed vegetation clearing (and no variations in sea surface temperature). What we did have were simulations where a “natural” land surface-atmosphere feedback was disabled. Disabling the feedback did reduce the amplitude of the rainfall anomalies produced by the oceanic influence. That is also in the 2003 article. So, in this sense, Charney’s bio-geophysical feedback is demonstrated, but again, as a feedback, and natural process, not as the primary disruptive process leading to persistent drought.

There are no direct comparisons of the two influences in models, in part because in the end the long-term history of land clearing is unknown: there are no satellite measurements going back to the 1950s :-)
And there is a long history of misconceptions around extrapolations of such trends (see the critical work of Fairhead and Leach, for example).
As you probably know, in fact, when people started to look at trends in vegetation cover from satellite in the Sahel, in the early 1990s, they were expecting desertification. Instead, they did not find any inexorable southward creeping of the desert, but they did find a strong influence of rainfall. I am referring, for example to:

Tucker, C.J., Dregne, H.E. and Newcomb, W.W., 1991. Expansion and contraction of the Sahara Desert from 1980 to 1990. Science, 253(5017), pp.299-300.
Helldén, U., 1991. Desertification: time for an assessment?. Ambio, pp.372-383.

Later on they found outright greening:
Herrmann, S.M., Anyamba, A. and Tucker, C.J., 2005. Recent trends in vegetation dynamics in the African Sahel and their relationship to climate. Global Environmental Change, 15(4), pp.394-404.

Finally, yes, I can say something about the likelihood of greater intensity and variability — it is what we are seeing now.

Panthou, G., Lebel, T., Vischel, T., Quantin, G., Sane, Y., Ba, A., Ndiaye, O., Diongue-Niang, A. and Diopkane, M., 2018. Rainfall intensification in tropical semi-arid regions: The Sahelian case. Environmental Research Letters, 13(6), p.064013.

Taylor, C.M., Belušić, D., Guichard, F., Parker, D.J., Vischel, T., Bock, O., Harris, P.P., Janicot, S., Klein, C. and Panthou, G., 2017. Frequency of extreme Sahelian storms tripled since 1982 in satellite observations. Nature, 544(7651), pp.475-478.

Salack, S., Klein, C., Giannini, A., Sarr, B., Worou, O.N., Belko, N., Bliefernicht, J. and Kunstman, H., 2016. Global warming induced hybrid rainy seasons in the Sahel. Environmental Research Letters, 11(10), 104008.

Giannini, A., Salack, S., Lodoun, T., Ali, A., Gaye, A.T. and Ndiaye, O., 2013. A unifying view of climate change in the Sahel linking intra-seasonal, interannual and longer time scales. Environmental Research Letters, 8(2), 024010.

warm regards, alessandra

Jane O'Sullivan

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May 18, 2021, 9:20:41 AM5/18/21
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Thank you so much Alessandra, for that thorough response. 
I think there is much work to be done in the adaptation space on resilience against more intense and less predictable rainfall. However, that is not so much a topic for demographers.
Jane

From: Alessandra Giannini <ale...@iri.columbia.edu>
Sent: 18 May 2021 21:56
To: Jane O'Sullivan <j.osu...@uq.edu.au>; Population-Environment Research Network (PERN) cyberseminars <pernse...@ciesin.columbia.edu>

Jane O'Sullivan

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May 19, 2021, 6:27:45 AM5/19/21
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Dear Guido, 
Thank you for your contribution. I agree with what you have said, but it doesn't satisfy my question. 

I would like to see some attention given to the role of population growth in generating poverty, insecurity and displacement. In saying this, I am not dismissing poor governance, misuse of power or any other cause of poverty. I am merely wondering why a forum for demographers does not have more to say about the obvious impacts of population growth. 

In response to your comment, I suggest that, where "there are instances where nominally low economic indicators are associated with relatively high quality of life and security," there is likely to be relatively low population pressure and sufficient natural resources per person. Their "nominally low economic indicators" can be attributed to a relatively small role for the monetary economy in meeting their needs. It is in contrast to this situation that population pressure changes the face of poverty: an insufficiency of natural resources per person leads to the pursuit of monetary income, and too many people competing for too few jobs leads to low remuneration and under-employment. 

Hence, I agree that it would be wrong to say that "security depends on poverty." But what I suggested was "the effect of population growth on security depends largely on poverty." My intention was to acknowledge that, for example, population growth in Canada has more impact on climate change than population growth in Yemen, but population growth in Yemen has more impact on insecurity than population growth in Canada. So, given the topic of this forum is focused on insecurity and drivers of displacement, I did not think that Tom's assertion that "the effect of population depends on the level of affluence, patterns of consumption, etc." captured the relevant context for us. Apologies if I didn't make that clear.

Jane

From: Cervone, Guido <gu...@psu.edu>
Sent: 18 May 2021 00:52

To: Jane O'Sullivan <j.osu...@uq.edu.au>

Subject: Re: [PERN Cyberseminar] Population growth as a driver of displacement
 
Hello Jane and all,

I think that the statement “… the effect of population growth ON SECURITY depends largely on poverty” puts the emphasis on the wrong stressor.  While it is undeniable that there is a strong correlation between poverty and security, it is not poverty itself that affects security, but the conditions responsible for poverty.   Bad governance, mismanagement of resources, among many, are the main stressors, and poverty is a consequence.   There are instances where nominally low economic indicators are associated with relatively high quality of life and  security.   Similarly, I am not convinced that the level of affluence alone is a good indicator for the effects on climate change.  

Guido


Guido Cervone
Associate Director of the Institute for Computational and Data Sciences (ICDS)
Professor of Geography, Meteorology and Atmospheric Science
Geoinformatics and Earth Observation Laboratory (GEOlab) — Earth and Environmental Systems Institute (EESI)
322 Walker Building — 40.793238N, 77.866867W — The Pennsylvania State University

President-Elect, AGU Natural Hazards

Affiliate Scientist, National Center for Atmospheric Research, Boulder, CO
Affiliate Professor, Instituto Sant’ Anna, Italy

Richard Seager

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May 19, 2021, 7:15:40 AM5/19/21
to Jane O'Sullivan, Cervone, Guido, Tom Dietz, Ilan Kelman, pernse...@ciesin.columbia.edu
Hi Jane,

I must say I have found this debate disturbing.
I am a physical scientist who also does some work on migration.  First of all, I am an enthusiastic supporter of giving power to people to control their own fertility and I do recognize the need to reduce fertility for the purpose of development and climate change mitigation, so no argument there.
However the idea of the “carrying capacity” of land puzzles me … on the face of it the Netherlands and Israel have huge carrying capacities (pop’n density) but that is not because of natural resources but a powerful place in the global economy.  I do not see that carrying capacity can be separated from the global economy.  If the price of coffee was 10 times higher then the “carrying capacity” of Guatemala would be much larger.  If the price of oil was a lot lower then the carrying capacity of Bahrain would be lower.  I think the whole idea of a limit to how many people land can support is problematic.
Second pointing to population as a dtiver of migration leads to inevitable right wing backlash.  Consider the current migration form Central America to the US.  Sure a case can be made that population growth is too large in Central America.  However what we also see there is the tremendous pressure to migrate from decades of (US-backed) war, corruption, drug gang violence, hurricanes, and static prices for crops in a global economy.  If that argument for why people are migrating is not central then the right will simply say ‘it is their fault for being poor, they have too many children, its’ nothing to do with us, keep them out’. 
Interestingly, the migration to the US at the southern border is newly aflush with Venezuelans - the largest migrant crisis in the hemisphere now and now impacting the US - which seems to be a case of migration from a country with a high natural resource base that has fallen on bad times due to an appaling political situation.

Cheers,
Richard


Richard Seager
Palisades Geophysical Institute/Lamont Research Professor
Lamont Doherty Earth Observatory of Columbia University
61 Route 9W, Palisades, NY 10964
sea...@ldeo.columbia.edu
Tel: 845-365-8743
“Who wants it all a bed of roses anyway?”, Lal Waterson, Memories.



Jane O'Sullivan

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May 19, 2021, 8:30:44 AM5/19/21
to Ilan Kelman, pernse...@ciesin.columbia.edu
Dear Ilan, 
Thank you for the further discussion.

Having learned from this exchange, perhaps I could reframe my question, to:

"What proportion of currently internally displaced people, refugees and asylum seekers do not have population growth as a factor contributing to the circumstances from which they fled?"

My other question, to which nobody has responded, was: 

"Is it reasonable to imagine that people displaced from a conflict or famine resulting from overpopulation can ever go home without recreating the crisis?"

I have now read your "Population and Sustainability" paper. It discusses influences of demography (population density, gender etc.) on the impact of natural events on communities. It does not discuss humanitarian crises that are predominantly of human making. Perhaps that's why you dismiss the utility of the term "natural disaster" - is it that anthropogenic disasters are not your focus of study? Many humanitarian crises have a "natural" trigger (such as drought) but the underlying tensions of population pressure had lowered resilience to the point where these events caused cascading crises rather than transient hardship. Such circumstances apply to most displaced people. Displacements due to volcanic eruptions and tsunamis are relatively rare, usually more limited in scale and more rapidly resolved. Hence my reframed question.

I also looked briefly at your other papers (a) to (d) and found no enlightenment. Indeed, they seem to consistently avoid mentioning population growth as a contributor to the "historical vulnerabilities".

Jane

P.S. The "you and 99% of people" referred to the belief that educating girls is the best driver of fertility decline, not to whether or not disasters are "natural". 


From: Ilan Kelman <ilan_...@hotmail.com>
Sent: 18 May 2021 01:20

Jane O'Sullivan

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May 19, 2021, 8:43:43 AM5/19/21
to Richard Seager, Cervone, Guido, Tom Dietz, Ilan Kelman, pernse...@ciesin.columbia.edu
Hi Richard, 
Then I guess we must agree to disagree on the ethics of self-censorship.
Jane

From: Richard Seager <sea...@ldeo.columbia.edu>
Sent: 19 May 2021 21:14

To: Jane O'Sullivan <j.osu...@uq.edu.au>

sesa...@aol.com

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May 19, 2021, 10:57:09 AM5/19/21
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Dear Jane, Richard, Guido, Tom and Ilan,

Good day to all. Perhaps an article on carrying capacity is useful in the context of this discussion, with special attention to Richard's comment below.


This article is directly derived from original research by Hopfenberg and Pimentel regarding the hypothesis that food is a fundamental basis of population numbers of the human species, just as it is for other species within the "web of life of earth".


Thank you for this edifying discussion. 

All the best,

Steve


-----Original Message-----
From: Jane O'Sullivan <j.osu...@uq.edu.au>

Colin Butler

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May 19, 2021, 10:57:13 AM5/19/21
to Jane O'Sullivan, Richard Seager, Cervone, Guido, Tom Dietz, Ilan Kelman, pernse...@ciesin.columbia.edu

Dear Richard, Jane and others,

 

I have found parts of this discussion of sufficient interest to chime in.

 

Firstly, Richard, thank you for being an enthusiastic supporter "of giving power to people to control their own fertility" and also for recognizing "the need to reduce fertility for the purpose of development and climate change mitigation", there is no argument with me there.

 

However, I was dismayed by your characterisation of carrying capacity as of “land”. Land is but one aspect of natural capital (as you clearly know). It is now almost 19 years since Tony McMichael and I wrote a paper for an IUSSP meeting in Rostock (https://www.demogr.mpg.de/papers/workshops/020619_paper25.pdf), in which we proposed Human Carrying Capacity (HCC) is better conceptualised as the interaction of 5 capitals (natural, built, human, social and financial). I’m not claiming that as a profound insight, even at the time, the ideas seemed pretty obvious to me years earlier, I recall being dismayed that Joel Cohen’s book ignored the issue of conflict, an aspect of social capital,

 

However, in the years since, I have repeatedly experienced a failure to be understood on this, both by physical scientists (as you describe yourself) and also by many social scientists. Partly for that reason I very rarely contribute to PERN seminars, although I do keep writing about HCC. 

 

Thus, I agree that HCC cannot be considered without consideration of the global economy. Places with high and generally affluent population densities (Israel, Hong Kong, Netherlands etc) are easily explained using the 5 capitals approach because they have sufficient total capital, not necessarily only natural. Indeed, places with high natural capital, alone, often have low HCC (resource trap). 

 

(BTW, as far as I know, Venezuelan physical resources are far from abundant, as oil sands have a low energy return on energy investment.)

 

**

 

However, I am sympathetic to your point that the US Right Wing will not be sympathetic to any argument stating that emigration from pockets of what I call “regional overload” is driven in part by a higher fertility than their regional HCC allows. 

 

But in my opinion they are not likely to be sympathetic in any case. 

 

I have also long argued that neoliberalism has played an important role in suppressing the pop’n debate, particularly since the 1980s in the run up to the Mexico City meeting. I also argue that the other half of the coin of laissez faire pop’n growth is strict border control; variants of Hardin’s "lifeboat economics”. So (though unspoken), even if high pop’n growth with free markets in low income settings leads to problems (ie the magic formula of marketism fails to generate promised prosperity for poor people with high fertility) the global North would still win - with cheap labour in the South, in-migration (skilled and less skilled) at a manageable trickle to the North, and fence the rest out if necessary. The theory, of course, breaks down once actors in the South have access to rockets, terrorist martyrs and cyber-crime .. still it’s partly manageable.

 

__

 

Now I will say something which is an appeal for a new alliance, but risks misinterpretation. One of my mentors, Maurice King, often talked in favour of benign uproar (debate) as opposed to malignant uproar (Gaza, Guatemala, Venezuela etc). So apologies if this next sentence leads to benign uproar.

 

My sense is that we should be on the same side (and so should feminist authors such as the authors of 'Malthus’s specter and the Anthropocene', Gender, Place & Culture. A Journal of Feminist Geography: doi: 10.1080/0966369X.2018.1553858. Diana Ojeda, Jade S. Sasser, and Elizabeth Lunstrum). But we are very divided. That is a great shame to me. Is it just academic turf-protecting? Is it more than that?

 

I agree with Jane about the ethics of self-censorship. I have at times self-censored, either to protect my livelihood, my emotions or to avoid work. But, when it comes to the issues which we discuss, which concern the lives of billions, don’t we have a duty of care to be as truthful as possible? We have already wasted decades in in-fighting; I think to be silent on this is to play right into the hands of those who ignore limits to growth, and who rationalise the suffering of other people and of nature (including the future) as somehow justifiable.

 

Best wishes

 

Colin

 

 

Colin Butler PhD, MSc, BMed, DTM&H 

Honorary Professor, National Centre for Epidemiology and Population Health, Australian National University, Australia

Member of Scientific Advisory Committee: Doctors for the Environment, Australia

https://researchers.anu.edu.au/researchers/butler-cdd
http://colindbutler.weebly.com/
http://www.bodhi-australia.com/
http://health-earth.weebly.com

colin....@anu.edu.au

 

 

From: Jane O'Sullivan <j.osu...@uq.edu.au>


Date: Wednesday, 19 May 2021 at 10:13 pm
To: Richard Seager <sea...@ldeo.columbia.edu>

Ilan Kelman

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May 19, 2021, 10:57:19 AM5/19/21
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Dear Jane,

Thank you for your notes and for the continuing discussion. In response to all your questions, noting that you did not answer some of mine (e.g. "Why would it be valuable to claim that they are 'exceptions that prove the rule' without providing any evidence for this statement?"):

A. "What proportion of currently internally displaced people, refugees and asylum seekers do not have population growth as a factor contributing to the circumstances from which they fled?"

Quantification at this level might perhaps not be the most useful question to ask, because population growth, population numbers, and population densities are important to examine and consider in 100% of instances. The analysis methods will vary according to need and situation. This specific question could be interesting and have usefulness for pure research if people wish to pursue it, yet care would be needed in interpreting the quantitative results for policy and practice without sensitivity analyses while indicating possible sources of aleatory and epistemic uncertainties, both in order to indicate the impacts of assumptions made.

B. "Is it reasonable to imagine that people displaced from a conflict or famine resulting from overpopulation can ever go home without recreating the crisis?"

Yes, keeping in mind that the mobilities literature for decades has been clear that a single factor rarely directly causes displacement with no other influences. See, for instance, https://www.oxfordhandbooks.com/view/10.1093/oxfordhb/9780199652433.001.0001/oxfordhb-9780199652433 and https://www.uclpress.co.uk/products/116728 and I would be happy to provide many more, if these would not suffice. Statements such as "a conflict or famine resulting from overpopulation" are inadequate for describing reality, as it could be interpreted (possibly unintentionally) as presuming that overpopulation is the only causal factor in some (not all or even necessarily many) conflicts or famines. For the latter, see of course work by Amartya Sen, Stephen Devereux, and George Kent. Nonetheless, as one generic yet grounded example--within the context of the request "to imagine"--there are sad situations where population numbers in a location are severely reduced by mortality, non-returnees, or a combination. In such situations, people who return might imaginably be able to do so without recreating the crisis, because the population numbers and structures have substantially changed.

C. "is it that anthropogenic disasters are not your focus of study?"

This question shows that the past decades of disaster science remain as a needed reading list. Almost all disasters are anthropogenic, with exceptions detailed in the publications I already provided in my initial reaction to the phrase "natural disasters". I have sent numerous further sources explaining this point, some of them more than once, so perhaps it would be appropriate to please consider spending more time reading these scientific publications rather than focusing on the oft-repeated statement (or similar) of "looked briefly"? As I typically explain to students, it is remarkable how reading a piece rather than glancing through it (or just looking at its title) does indeed convey detailed information about what the author is saying. For example, the claim that "they seem to consistently avoid mentioning population growth as a contributor to the 'historical vulnerabilities'" is contradicted by the trio of illustrative examples (there are more) of (i) pages 45-57 of https://global.oup.com/academic/product/disaster-by-choice-9780198841340 (sent earlier); (ii) the paper https://jpopsus.org/full_articles/disaster-vulnerability-by-demographics which you say you read and then dismiss on the basis of erroneous assumptions about "natural events"; and (iii) point 3 on page 23 of https://doi.org/10.1007/s13753-015-0038-5 which is specifically about population numbers. The material here understandably might not be specifically how you would address the topics while numerous aspects are certainly missing and they might not use the exact vocabulary you are used to. In fact, I have yet to publish anything which is comprehensive or which appeals to every single scientific discipline. These provisos are a long way from your false accusation that the topic is absent. For me, I find it constructive and productive to read people's publications rather than publicly (or even privately) misrepresenting them--without having actually read them. Where I feel their work might be inadequate, I then do my own research and publish in order to contribute to filling in gaps. Gaping holes and lack of appeal to everyone nonetheless remain in all of my work.

On the note of supposedly "natural events", might it possibly be interesting to read in detail references explaining how much of nature we influence, part of which (not all of which) relates to population numbers leading to these influences? From earthquakes https://doi.org/10.1016/j.earscirev.2017.07.008 to floods https://doi.org/10.1130/0091-7613(2001)029%3C0875:FETFC%3E2.0.CO;2 to droughts https://www.nature.com/articles/267192a0 storms https://doi.org/10.1175/BAMS-D-18-0194.1 many so-called "natural" phenomena have a significant human influence. I leave as an exercise to you to find numerous examples of human activities influencing lava and tsunami parameters. Your wonderful 99% (I understood your point, but you apparently missed mine, which is why I repeat it here) seem to neglect the science of hazards, instead sticking with long-eviscerated assumptions--even when provided with counterevidence that they do not read--and thus producing incorrect conclusions which disaster science had overturned over forty years ago. Useful starting points are https://www.nature.com/articles/260566a0 and https://www.routledge.com/Interpretations-of-Calamity-From-the-Viewpoint-of-Human-Ecology/Hewitt/p/book/9780367350796 which are important to read more than briefly.

For me, I frequently find how helpful it is to look at the science of a field before commenting. Your statement "Displacements due to volcanic eruptions and tsunamis are relatively rare, usually more limited in scale and more rapidly resolved" is contradicted by past centuries of experience, extensively documented in scientific publications, using detailed examples some of which I gave previously and supplemented by evidence in https://www.elsevier.com/books/volcanic-activity-and-human-ecology/sheets/978-0-12-639120-6 and https://doi.org/10.1016/j.jvolgeores.2008.01.036 (which need to be read in their entirety). For a quick fix of examples, I wrote in a previous message "Niua Fo’ou in Tonga in 1946, Tristan da Cunha in the South Atlantic in 1961 with return in 1963, Pinatubo in the Philippines in 1991, Manam in Papua New Guinea on-and-off since 2004". In each of these cases, some people have not returned, the situations had cross-continental impacts, none were rapidly resolved, and the disaster was caused by society, not by the volcano. If you would commit to reading the material in detail, then I would be happy to provide references for each one to support my statements. In terms of being "relatively rare", this would need to be quantified with a cross-hazard comparison rather than making an unevidenced claim. As a starting point for volcanoes, please see http://www.islandvulnerability.org/docs/Gaudru2007.pdf demonstrating that "relatively rare" might be hard to defend, depending on specific definitions. I leave tsunamis as an exercise for you to seek (i) data and (ii) comparisons with other hazards.

Leading to finally...

D. "why you dismiss the utility of the term 'natural disaster'"

I "dismiss the utility of the term 'natural disaster'" due to the citations which I have given above and in previous messages, to which I add https://practicalactionpublishing.com/book/527/development-in-disaster-prone-places and https://www.routledge.com/At-Risk-Natural-Hazards-Peoples-Vulnerability-and-Disasters/Blaikie-Cannon-Davis-Wisner/p/book/9780415252164 and https://elibrary.worldbank.org/doi/abs/10.1596/978-0-8213-8050-5 and...how many more would you like? They all deconstruct in various ways your unevidenced assumption that "the underlying tensions of population pressure had lowered resilience to the point where these events caused cascading crises rather than transient hardship" demonstrating that it is not so simple. None rejects population-related issues. They do place these topics within wider contexts, accepting population quantities and qualities as being among the many contributing factors to "natural disaster" being a misnomer. You might disagree which is fine--but then scientific explanations and evidence would be expected, rather than blanket statements with little meaning, no scientific support, and an absence of logical argumentation.

And before you chide me for using some old citations, as you did to another respondent, I already provided much more recent material, but you already stated that you chose not to read it thoroughly. Similarly, I am sympathetic to concerns regarding the amount of reading being asked of you, but I provided summaries and those were dismissed without giving any rationale, instead just repeating the myths which the summaries specifically explained were incorrect. Hope this helps and with best wishes for accepting what decades of science across numerous disciplines has evidenced and proven,
From: Jane O'Sullivan <j.osu...@uq.edu.au>
Sent: May 19, 2021 12:42

Ilan Kelman

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May 19, 2021, 10:57:30 AM5/19/21
to Population-Environment Research Network (PERN) cyberseminars
People might be interested in critics of and detractors from various "social capital" paradigms:
Best wishes and thank you for the discussion,

Ilan



From: Colin Butler <colin.bu...@gmail.com>
Sent: May 19, 2021 15:05
To: Richard Seager <sea...@ldeo.columbia.edu>
Cc: Jane O'Sullivan <j.osu...@uq.edu.au>; Cervone, Guido <gu...@psu.edu>; Tom Dietz <tdie...@gmail.com>; Ilan Kelman <ilan_...@hotmail.com>; pernse...@ciesin.columbia.edu <pernse...@ciesin.columbia.edu>; Marleen....@UGent.be <Marleen....@UGent.be>; Ariana Zeka (Staff) <arian...@brunel.ac.uk>; Devin Bowles <de...@atoda.org.au>; richard Grossman <ric...@population-matters.org>; Kerryn Higgs <kerr...@gmail.com>

Subject: Re: [PERN Cyberseminar] Population growth as a driver of displacement
Dear Richard, Jane and others,

I have found parts of this discussion of sufficient interest to chime in.

Firstly, Richard, thank you for being an enthusiastic supporter "of giving power to people to control their own fertility" and also for recognizing "the need to reduce fertility for the purpose of development and climate change mitigation", there is no argument with me there.

However, I was dismayed by your characterisation of carrying capacity as of “land”. Land is but one aspect of natural capital (as you clearly know). It is now almost 19 years since Tony McMichael and I wrote a paper for an IUSSP meeting in Rostock (https://www.demogr.mpg.de/papers/workshops/020619_paper25.pdf), in which we proposed Human Carrying Capacity (HCC) is better conceptualised as the interaction of 5 capitals (natural, built, human, social and financial). I’m not claiming that as a profound insight, even at the time, the ideas seemed pretty obvious to me years earlier, I recall being dismayed that Joel Cohen’s book ignored the issue of conflict, an aspect of social capital,

However, in the years since, I have repeatedly experienced a failure to be understood on this, both by physical scientists (as you describe yourself) and also by many social scientists. Partly for that reason I very rarely contribute to PERN seminars, although I do keep writing about HCC. 

Thus, I agree that HCC cannot be considered without consideration of the global economy. Places with high and affluent population densities (Israel, Hong Kong, Netherlands etc) are easily explained using the 5 capitals approach because they have high capital, not necessarily only natural. Indeed, places with high natural capital, alone, often have low HCC. 

(BTW, as far as I know, Venezuelan physical resources are far from abundant, as oil sands have a low energy return on energy investment.)

**

However, I am sympathetic to your point that the US Right Wing will not be sympathetic to any argument stating that emigration from pockets of what I call “regional overload” is driven in part by a higher fertility than their regional HCC allows. 

But in my opinion they are not likely to be sympathetic in any case. 

I have also long argued that neoliberalism has played an important role in suppressing the pop’n debate, particularly since the 1980s in the run up to Mexico City. I also argue that the other half of the coin of laissez faire pop’n growth is strict border control; variants of Hardin’s "lifeboat economics”. So (though unspoken), even if high pop’n growth with free markets in low income settings leads to problems (ie the magic formula of marketism fails to generate promised prosperity for poor people with high fertility) the global North would still win - with cheap labour in the South, in-migration (skilled and less skilled) at a manageable trickle to the North, and fence the rest out if necessary. The theory, of course, breaks down once actors in the South have access to rockets, terrorist martyrs and cyber-crime .. still it’s partly manageable.

__

Now I will say something which is an appeal for a new alliance, but risks misinterpretation. One of my mentors, Maurice King, often talked in favour of benign uproar (debate) as opposed to malignant uproar (Gaza, Guatemala, Venezuela etc). So apologies if this next sentence leads to benign uproar.

My sense is that we should be on the same side (and so should feminist authors such as the authors of 'Malthus’s specter and the Anthropocene', Gender, Place & Culture. A Journal of Feminist Geography: doi: 10.1080/0966369X.2018.1553858. Diana Ojeda, Jade S. Sasser, and Elizabeth Lunstrum). But we are very divided. That is a great shame to me. Is it just academic turf-protecting? Is it more than that?

I agree with Jane about the ethics of self-censorship. I have at times self-censored, either to protect my livelihood, my emotions or to avoid work. But, when it comes to the issues which we discuss, which concern the lives of billions, don’t we have a duty of care to be as truthful as possible? We have already wasted decades in in-fighting; I think to be silent on this is to play right into the hands of those who ignore limits to growth, and who rationalise the suffering of other people and of nature (including the future) as somehow justifiable.

Best wishes

Colin


Colin Butler PhD, MSc, BMed, DTM&H 

Honorary Professor, National Centre for Epidemiology and Population Health, Australian National University, Australia

Member of Scientific Advisory Committee: Doctors for the Environment, Australia

https://researchers.anu.edu.au/researchers/butler-cdd
http://colindbutler.weebly.com/
http://www.bodhi-australia.com/
http://health-earth.weebly.com

colin....@anu.edu.au


Jamon Van Den Hoek

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May 19, 2021, 11:59:20 AM5/19/21
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Thanks to all for this productive exchange. Respectful communication is the cornerstone of PERN Cyberseminars, and we thank you all for your commitment to civil discourse as you share your knowledge and ask questions of the community. 

-- Jamon

On Wed, May 19, 2021 at 7:58 AM Ilan Kelman <ilan_...@hotmail.com> wrote:

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Dear Jane,

Thank you for your notes and for the continuing discussion. In response to all your questions, noting that you did not answer some of mine (e.g. "Why would it be valuable to claim that they are 'exceptions that prove the rule' without providing any evidence for this statement?"):

A. "What proportion of currently internally displaced people, refugees and asylum seekers do not have population growth as a factor contributing to the circumstances from which they fled?"

Quantification at this level might perhaps not be the most useful question to ask, because population growth, population numbers, and population densities are important to examine and consider in 100% of instances. The analysis methods will vary according to need and situation. This specific question could be interesting and have usefulness for pure research if people wish to pursue it, yet care would be needed in interpreting the quantitative results for policy and practice without sensitivity analyses while indicating possible sources of aleatory and epistemic uncertainties, both in order to indicate the impacts of assumptions made.

B. "Is it reasonable to imagine that people displaced from a conflict or famine resulting from overpopulation can ever go home without recreating the crisis?"

Yes, keeping in mind that the mobilities literature for decades has been clear that a single factor rarely directly causes displacement with no other influences. See, for instance, https://www.oxfordhandbooks.com/view/10.1093/oxfordhb/9780199652433.001.0001/oxfordhb-9780199652433 and https://www.uclpress.co.uk/products/116728 and I would be happy to provide many more, if these would not suffice. Statements such as "a conflict or famine resulting from overpopulation" are inadequate for describing reality, as it could be interpreted (possibly unintentionally) as presuming that overpopulation is the only causal factor in some (not all or even necessarily many) conflicts or famines. For the latter, see of course work by Amartya Sen, Stephen Devereux, and George Kent. Nonetheless, as one generic yet grounded example--within the context of the request "to imagine"--there are sad situations where population numbers in a location are severely reduced by mortality, non-returnees, or a combination. In such situations, people who return might imaginably be able to do so without recreating the crisis, because the population numbers and structures have substantially changed.

C. "is it that anthropogenic disasters are not your focus of study?"

This question shows that the past decades of disaster science remain as a needed reading list. Almost all disasters are anthropogenic, with exceptions detailed in the publications I already provided in my initial reaction to the phrase "natural disasters". I have sent numerous further sources explaining this point, some of them more than once, so perhaps it would be appropriate to please consider spending more time reading these scientific publications rather than focusing on the oft-repeated statement (or similar) of "looked briefly"? As I typically explain to students, it is remarkable how reading a piece rather than glancing through it (or just looking at its title) does indeed convey detailed information about what the author is saying. For example, the claim that "they seem to consistently avoid mentioning population growth as a contributor to the 'historical vulnerabilities'" is contradicted by the trio of illustrative examples (there are more) of (i) pages 45-57 of https://global.oup.com/academic/product/disaster-by-choice-9780198841340 (sent earlier); (ii) the paper https://jpopsus.org/full_articles/disaster-vulnerability-by-demographics which you say you read and then dismiss on the basis of erroneous assumptions about "natural events"; and (iii) point 3 on page 23 of https://doi.org/10.1007/s13753-015-0038-5 which is specifically about population numbers. The material here understandably might not be specifically how you would address the topics while numerous aspects are certainly missing and they might not use the exact vocabulary you are used to. In fact, I have yet to publish anything which is comprehensive or which appeals to every single scientific discipline. These provisos are a long way from your false accusation that the topic is absent. For me, I find it constructive and productive to read people's publications rather than publicly (or even privately) misrepresenting them--without having actually read them. Where I feel their work might be inadequate, I then do my own research and publish in order to contribute to filling in gaps. Gaping holes and lack of appeal to everyone nonetheless remain in all of my work.

On the note of supposedly "natural events", might it possibly be interesting to read in detail references explaining how much of nature we influence, part of which (not all of which) relates to population numbers leading to these influences? From earthquakes https://doi.org/10.1016/j.earscirev.2017.07.008 to floods https://doi.org/10.1130/0091-7613(2001)029%3C0875:FETFC%3E2.0.CO;2 to droughts https://www.nature.com/articles/267192a0 storms https://doi.org/10.1175/BAMS-D-18-0194.1 many so-called "natural" phenomena have a significant human influence. I leave as an exercise to you to find numerous examples of human activities influencing lava and tsunami parameters. Your wonderful 99% (I understood your point, but you apparently missed mine, which is why I repeat it here) seem to neglect the science of hazards, instead sticking with long-eviscerated assumptions--even when provided with counterevidence that they do not read--and thus producing incorrect conclusions which disaster science had overturned over forty years ago. Useful starting points are https://www.nature.com/articles/260566a0 and https://www.routledge.com/Interpretations-of-Calamity-From-the-Viewpoint-of-Human-Ecology/Hewitt/p/book/9780367350796 which are important to read more than briefly.

For me, I frequently find how helpful it is to look at the science of a field before commenting. Your statement "Displacements due to volcanic eruptions and tsunamis are relatively rare, usually more limited in scale and more rapidly resolved" is contradicted by past centuries of experience, extensively documented in scientific publications, using detailed examples some of which I gave previously and supplemented by evidence in https://www.elsevier.com/books/volcanic-activity-and-human-ecology/sheets/978-0-12-639120-6 and https://doi.org/10.1016/j.jvolgeores.2008.01.036 (which need to be read in their entirety). For a quick fix of examples, I wrote in a previous message "Niua Fo’ou in Tonga in 1946, Tristan da Cunha in the South Atlantic in 1961 with return in 1963, Pinatubo in the Philippines in 1991, Manam in Papua New Guinea on-and-off since 2004". In each of these cases, some people have not returned, the situations had cross-continental impacts, none were rapidly resolved, and the disaster was caused by society, not by the volcano. If you would commit to reading the material in detail, then I would be happy to provide references for each one to support my statements. In terms of being "relatively rare", this would need to be quantified with a cross-hazard comparison rather than making an unevidenced claim. As a starting point for volcanoes, please see http://www.islandvulnerability.org/docs/Gaudru2007.pdf demonstrating that "relatively rare" might be hard to defend, depending on specific definitions. I leave tsunamis as an exercise for you to seek (i) data and (ii) comparisons with other hazards.

Leading to finally...

D. "why you dismiss the utility of the term 'natural disaster'"

I "dismiss the utility of the term 'natural disaster'" due to the citations which I have given above and in previous messages, to which I add https://practicalactionpublishing.com/book/527/development-in-disaster-prone-places and https://www.routledge.com/At-Risk-Natural-Hazards-Peoples-Vulnerability-and-Disasters/Blaikie-Cannon-Davis-Wisner/p/book/9780415252164 and https://elibrary.worldbank.org/doi/abs/10.1596/978-0-8213-8050-5 and...how many more would you like? They all deconstruct in various ways your unevidenced assumption that "the underlying tensions of population pressure had lowered resilience to the point where these events caused cascading crises rather than transient hardship" demonstrating that it is not so simple. None rejects population-related issues. They do place these topics within wider contexts, accepting population quantities and qualities as being among the many contributing factors to "natural disaster" being a misnomer. You might disagree which is fine--but then scientific explanations and evidence would be expected, rather than blanket statements with little meaning, no scientific support, and an absence of logical argumentation.

And before you chide me for using some old citations, as you did to another respondent, I already provided much more recent material, but you already stated that you chose not to read it thoroughly. Similarly, I am sympathetic to concerns regarding the amount of reading being asked of you, but I provided summaries and those were dismissed without giving any rationale, instead just repeating the myths which the summaries specifically explained were incorrect. Hope this helps and with best wishes for accepting what decades of science across numerous disciplines has evidenced and proven,

From: Jane O'Sullivan <j.osu...@uq.edu.au>
Sent: May 19, 2021 12:42

Ben Wisner

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May 19, 2021, 1:46:14 PM5/19/21
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Not dismissing population, Jane, but putting it in perspective and context, in my view.

Younger researchers should perhaps be reminded of the work of people such as Ester Boserup:

Boserup, Ester (1965). The conditions of agricultural growth: the economics of agrarian change under population pressure. London: Allen & Unwin. OCLC 231372. Pdf version.
Reprinted as: Boserup, Ester (2005). The conditions of agricultural growth: the economics of agrarian change under population pressure. New Brunswick, New Jersey: Aldine Transaction. ISBN 9780202307930.

Best wishes,
BEN

On Sun, May 16, 2021 at 7:08 PM Jane O'Sullivan <j.osu...@uq.edu.au> wrote:
Hello to the panelists and participants, 

Thank you to all for an interesting discussion. However, one area seems oddly neglected in this discussion. Do demographers have nothing to say about the role of population pressure in causing the circumstances from which people flee?

Jalal said in the webinar that demographic drivers act in concert with other drivers. This seemed to be a way of dismissing further examination of demographic drivers. Yet it would be more accurate and enlightening to say that other drivers act in concert with demographic pressure. Can any of them be properly understood without referencing the underlying effects of population growth?

Clearly there are natural disasters that are independent of demography, but normally they only displace people locally and temporarily. Even there, there is also an influence of demographic pressure placing more people in harm’s way – onto floodplains or beach fronts or steep slopes which people avoided in the past due to their hazards, but which now support dwellings because there is nowhere else to expand into.

Can anyone name any instances where long-term displacement of people has not involved an underlying stress of overpopulation?

Is it reasonable to imagine that people displaced from a conflict or famine resulting from overpopulation can ever go home without recreating the crisis? Their numbers would be replaced within a few years.

Migration literature, particularly under the “new economics of labour migration” (NELM) theory, tends to ignore population growth as a driver of migration. Analyses typically present the decision of a household to send migrants as one of income diversification and self-insurance. For example, Taylor (2002) https://doi.org/10.1111/1468-2435.00066 sees rural-urban migration as a phenomenon driven by GDP growth and its implicit link with economic diversification, and suggests that constraints on local production and livelihoods are due to “market failures” such as inadequate market access, finance and insurance systems.  The presumption is that, without climate change or other exogenous factors undermining livelihoods, the economic situation would be stable or gradually improving due to development, and migration offers a means to enhance development. But nothing is stable where populations are growing. The climate migration literature does not discuss the common reality that the alternative to out-migration from rural areas is an ever-dwindling allocation of natural resources per household (arable land, water, or access to common forest, pasture or fishing resources),  and the inevitable degradation of those resources due to overuse.  Equally absent is any recognition that such subdivisions and degradations over the past two generations have contributed to the impoverishment of households, and their vulnerability to adverse weather events and their proclivity to use violence to defend their resources or to capture someone else’s.

Have demographers got nothing to contribute to an understanding of population pressure?

Jane O'Sullivan


Tom Dietz

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May 19, 2021, 2:53:58 PM5/19/21
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I appreciate the long debate about the nuances of including or not including social networks, trust etc. on equal footing with other forms of "capital."  My read is that no one argues that these things are unimportant; the debate is more about how to conceptualize them--do we want  everything considered "capital"?

As a sociologist I have argued that  we should be cautious about the term capital, which in one meaning is something that is used to make profit.  I argue we should think about human resources, financial resources, natural resources that are used to produce human well-being.  I would use the term capital only for the special case where they are being deployed within capitalist institutional arrangements.  That is common, but not universal.  I've written a bit about this and would be happy to share the paper.
Dietz, Thomas. 2015. "Prolegomenon to a Structural Human Ecology of Human Well-Being." Sociology of Development 1(1):123-48.

ALHAJ HAJHAMAD

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May 20, 2021, 10:42:19 AM5/20/21
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Dear All,
Before the Chinaes merical the The poverty population growth nexuses was asocial marketing tool.Now it is an asset for development.But under all circumctances the natural resource management is decisive.
Thanks
Hajhamad
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Md Jalal Abbasi

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May 20, 2021, 10:43:27 AM5/20/21
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Dear colleagues,

This discussion is helpful to all of us considering the evidence and approaches to analysis, and perhaps more importantly to consider the most humane and just means to address drivers of high population growth relative to the resources that are effectively accessible to members of those populations.  The comments made provide further food for thought for our future research, and we try to add the following points:

Studies have found that simplistic “overpopulation” view to be inconclusive and unconvincing over the years. That has led demographers and other strategic planners and analysts to apply unconventional approaches such as system dynamic approach as well as agent-based modeling in the explanation and predictions of the issues particularly population and climate change nexus for two main reasons:

One is the fact that, as we alluded in our paper, climate impacts are divided into climate processes and climate events. Thus, in addition to the static analysis of the impacts or correlates of demographic characteristics on climate change (vise versa) at one point of time, one should consider the long-term impacts using dynamic approaches.   

The second reason is that several drivers (including population growth and size) should be considered at different levels of individual, household, community, national, regional, and international to determine the causes and consequences of environmental change, population growth and displacement.

Recent studies including Lutz et al (2002) have shown that the impacts of population composition (age, education, etc) on natural resources and environment, water scarcity etc are more noticeable.

Lutz, W., A. Prskawetz, and W.C. Sanderson, Eds. 2002. Population and Environment. Methods of Analysis. Supplement to Population and Development Review, Vol. 28, 2002. New York: The Population Council.

 

In particular, education has been found to be one of the important variables on population control policies, contraceptive use as well as other demographic, social, political and environmental/climate changes.  Here are some useful and relevant references:

Lutz, W., Butz, W., and and KC, S. (eds.) 2014, World Population and Human Capital in the Twenty-First Century, Oxford University Press, Oxford.

 

Muttarak, R. and W. Lutz. 2014. Is education a key to reducing vulnerability to natural disasters and hence unavoidable climate change? Ecology and Society 19(1): 42.
http://dx.doi.org/10.5751/ES-06476-190142

 

Lutz, W., Crespo Cuaresma, J., M.J. Abbasi-Shavazi, 2010, Demography, Education and Democracy: Global Trends and the Case of Iran, Population and Development Review, 36(2): 253-281.

 

Having said this, of course, using dynamic and multilevel approaches in our analysis is a complex process particularly with the lack of cross-sectional and longitudinal data.  However, demographers have learned to use insufficient and incomplete data to come up with relatively accurate measures. This means that we should encourage our fellow demographers and other scientists to be engaged in the discussions and analysis to find more convincing answers to the questions raised in this forum and beyond. Training the new generation of demographers who would be able to pay attention to more multidisciplinary research and apply innovative techniques using incomplete data and considering the mutual relationship between environmental change and population displacement is a priority for our discipline.

We appreciate the discussions by our colleagues thanks to the initiation by PERN.  Ellen and I cannot begin to speak to all demographers.  We do, however, give focus to the components of population change and suggest that in addition to the provision of health services and health education to women, particular attention be given to girls' education and instruction as well as support for household economies.  As such, investment in the present and future generations of healthy children.

We assure you that we shall make efforts, as we have done in the past, to discuss these issues in our discipline in order to mainstream the climate change and population issues. Our goal is, of course, to improve policies to mitigate the impacts on well-being of the affected populations and to preserve our climate and environment.

Jalal and Ellen

-------------------------------------------------------
Professor Mohammad Jalal Abbasi-Shavazi
Department of Demography, University of Tehran,
President, Population Association of Iran, &
Council Member, International Union for the Scientific Study of Population (IUSSP)
Email: mab...@ut.ac.ir
-------------------------------------------------------


Wrathall, David J

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May 20, 2021, 10:49:13 AM5/20/21
to Ben Wisner, Jane O'Sullivan, Population-Environment Research Network (PERN) cyberseminars, bwi...@igc.org, benjam...@googlemail.com
Dear Ben, Jane, Richard, Ian, Colin, Alessandra, Guido, et al., and bystanders in the PERN community,

Ben, thanks for refocusing us on the imperatives of poverty. As we've known since at least Bosrup (1965) --or, if you've been poor, much earlier than that!-- in the absence of a state-provisioned safety net, the poor depend on a social fabric to amplify household economic opportunities and mitigate risks --a network that they themselves fashion from kinship. Your children are your safety net. So then, institutional safety nets, poverty and fertility are inextricable considerations. Likewise, as is established in volumes of empirical literature, while hazards may be "natural," disaster impacts (such as famine) are inextricable outcomes of both hazards and people's sensitivity to environmental change, and capacity to manage risk!  Again the inextricable interplay between institutional context and individual concerns. It seems that, rather than following causal rules, many problems emerge from complex interplay between institutions and people, and are generations in the making. 

Consider this emergent problem (which our convener and moderator Jamon Van Den Hoek is helping us address in the forthcoming IPCC Sixth Assessment): the future climate vulnerability of refugee camps. From our vantage point in 2021, we can already look to the end of the 21st century, and see that current refugee camps are located in areas where absolute temperatures will be highest in 2100 under all emissions scenarios. However from our current vantage point, it is also completely obvious that future climate disasters in refugee camps are not an environmentally (pre)determined outcome, but rather a result of present-day institutional factors --decisions made by states and international agencies!-- that maintain refugees in camps over generations. Future climate vulnerability in refugee camps depends more on, for example, whether refugees are free to migrate freely within host countries, or whether industrialized countries in the Global North assume greater refugee hosting responsibilities. From our vantage point looking forward, it is abundantly clear that fertility (for example) is not the overriding issue in refugees' future climate vulnerability! (We should apply the same historical lenses when examining current climate vulnerability.)

Moving from basic knowledge to actionable knowledge, especially as we step into the "solutions space" of spelling out policy interventions, it is likewise critical for us to recognize problems as dynamics that emerge between institutions and people through history.  In the Central American context (where some of this discussion on displacement/refugees is focused) an extremely common question is: Why is Costa Rica so relatively stable and more prosperous in comparison to its neighbors in the Northern Triangle, in which we find the highest poverty and homicide rates in the Western Hemisphere? Ha! The answer is complicated, to be sure. But (to take the bait) it has to do Costa Rica's long-term project of refashioning institutions in line with a vision of broad-based development (e.g. Costa Rica abolished its army in 1948 and reallocated resources to healthcare, education, and land reform --a much more involved story, which we do not have space to retrace here). The answer to the question about Costa Rica's peculiarity is the same reason that it has a robust national parks system and a thriving medical technology sector. It's a complex emergent interplay between institutions and people. Examples such as these urge us to be patient with "solutions" that require generations in order to alter dynamics and obtain desired outcomes. 

Just a couple of thoughts. Thanks everyone for an engaging discussion!
David
--
David J. Wrathall PhD
Assistant Professor | College of Earth, Ocean and Atmospheric Sciences | Oregon State University
Lead Author | Intergovernmental Panel on Climate Change, WG II, Ch. 8 Poverty, Livelihoods and Sustainable Development
348a Strand Hall | Corvallis, Oregon 97331-5503
tel: +1 541 737 8051 | cell: +1 831 239 8521 | skype: davidjwrathall 

Get a sneak-preview of the framework for understanding migration and climate change in the IPCC's AR6 now in Climatic Change. Read about sea level rise and future migration in Nature Climate Change, and see our compelling prediction in Environmental Research Letters, that as the sea level rises in Bangladesh, migrants will actually move towards the coast! 

In Global Environmental Change read about the effects of narco-trafficking on conservation governance in Central America! In the same issue, we make the case that narco-trafficking causes deforestation.




On Wed, May 19, 2021 at 10:48 AM 'Ben Wisner' via PERNSeminars - List <pernse...@ciesin.columbia.edu> wrote:

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Not dismissing population, Jane, but putting it in perspective and context, in my view.

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May 23, 2021, 7:44:46 PM5/23/21
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Dear All,

Has anyone seen, examined or critiqued the article which is referenced in the following link?


Abstract

We assume that human carrying capacity is determined by food availability. We propose three classes of human population dynamical models of logistic type, where the carrying capacity is a function of the food production index. We also employ an integration-based parameter estimation technique to derive explicit formulas for the model parameters. Using actual population and food production index data, numerical simulations of our models suggest that an increase in food availability implies an increase in carrying capacity, but the carrying capacity is “self-limiting” and does not increase indefinitely.

Very best regards,
Steve
PS: Please recall Hopfenberg's 2003 article, (21) (PDF) Human Carrying Capacity Is Determined by Food Availability (researchgate.net), which incidentally provides the foundation for the mathematical modelling of human carrying capacity as it relates to food availability.

Thank you,

Steve Salmony


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May 24, 2021, 1:30:41 PM5/24/21
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Dear Jane,

You are kind to have responded just as you have. I find agreeing with you most appealing. Your research and that of Colin Butler, M.D. provide us with some of the most incisive and helpful evidence about the natural conditions of being human. That said, the three of us have a history of disagreeing about certain critical items.

Given the dire existential situation in which we find ourselves in 2021, there is no time to waste.  Please, everyone, examine another new paper that call out for rigorous scrutiny. I want to post it here with the hope that it leads to a deep and broadened discussion of why absolute global human population numbers continue increasing annually by 80+/- million, despite declining total fertility rates in most nation-states on the surface of earth.

 Please find the article at the following link.  https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0247214

Jane, I want to take another moment to thank you and Colin (who I met almost two decades ago) for the remarkable contributions each of you has made to protect Earth's biodiversity from mass extirpation, its environs from relentless degradation, its body of reckless dissipation, and its integrity as a fit place for human habitation and the continuing evolution of life. Needless to say, comments from one and all are welcome in response to valuable emerging science.

With every good wish, I am

Sincerely yours,

Steve


-----Original Message-----
From: Jane O'Sullivan <j.osu...@uq.edu.au>
Thanks for posting this, Steve. I hadn't seen it. 

However, my reading of it is that it is purely a mathematical exploration that doesn't consider what the actual limits on food production are going to be, nor how they act to limit population. It calibrates on past population and food production figures, but it doesn't consider how the different pathways of growth in productivity, growth in area of land used and growth in water applications have contributed to growth in food production, nor how much suitable land and water remain, nor the dynamics of degradation of land and water resources that will take productive capacity out of the system. For all those reasons, it can make no useful prediction of future population dynamics. 

That's before factoring any other potential limit to human carrying capacity. I agree with them that, if and wherever humans push the envelope too far, food will be the crux of it. But disruptions to energy supply, pandemic or political upheaval, for instance, could impact on food production and distribution to bring on localised crises in ways that a projection of global food production capacity would not anticipate. 

Does anyone have another take on it?

Jane