Posts Tagged ‘population’

People, resources, and conflict

Saturday, January 28th, 2017

Are you dreaming of a lost Golden Age? Are you sharing Rousseau’s view of a primeval state of nature blessed with peace and harmony? Do you believe that our ancestors lived in balance with nature? Sorry to break your romantic dream. Growing evidence pictures out a different story, one of widespread competition over resources and scarcity-induced conflict. Yesterday, and today.

The most common human story is neither balanced nor quiet. When prehistoric human groups colonised new, richer territories, a period of abundance usually followed. Unfortunately, far too often that produces to population growth and the consequent overexploitation of local resources, triggering a crisis leading to starvation and the need to move further away. The colonization of New Zealand by Polynesian people in the late 13th century, which led to the extinction of at least nine species of moa (large, wingless birds), perfectly represents this pattern. The same happened in many other Pacific islands where, when moving was no longer possible, groups declined or disappeared. When possible, the alternative to starvation was to steal resources from some more lucky neighbours, which often requires to chase them out of their land, or simply to kill them.

The well known popular science writer Jared Diamond is an early proposal of this story (also included in his recent book The World Until Yesterday), so did Clive Ponting in his inspiring Green History of the World. Evidence is growing that they are right. For instance, Mark Allen and colleagues found a clear link between resource scarcity and lethal violence among prehistoric hunter-gatherers in Central California. Nor were early European farmers much better, as shown by the repeated findings of mass graves with victims holding signs of systematic torture and violent death.

The same may have also happened on a much larger scale. A research I recently co-authored shows that human population dynamics in South America 9000 to 5000 years ago cannot be explained without taking into account widespread migration and conflict. What we did is simply to check the ability of two models to reproduce the continental population dynamics recently reported in a Nature paper. In the first, only local natural resources were exploited by human groups, while in the second they had the possibility to move to already occupied neighbouring areas in case of scarcity. The latter model was the only able to correctly reproduce the empirical data, with the logical conclusion that migration and conflict affected human demography at the scale of a whole continent long before globalization and long distance mass transport.

Resource scarcity plays a role in today’s violence and conflicts as well. For instance, among the causes of the Syrian war lies a dramatic stress over domestic water resources due to the growth of the country population, bad agricultural practices, and a multi-year drought, the latter plausibly linked with climate change. In general, changes in the climate and rainfall regime have historically acted as triggers for conflict, especially in situations already presenting factors that produce social tension, such as ethnic divides.

The situation seems not so different in other parts of the world. Failing states represents today one of the main threats to world security. The international displacement of people that the world has experienced in the last few years may well become the norm in the close future. All that can be linked together by what we learned from history. Far too often humans reached the limit of the environment where they lived. That not only led to poverty and starvation, often also to conflict, warfare, and genocide.

I obviously don’t like these solutions to what, ultimately, are resource scarcity problems. No sane person would. That does not make the study of environmental conflicts less important. Far too often we base our policies and proposed solutions to the problems of the world on an idealised picture of humans and their behaviour. Some blame ridiculous conspiracies (from reptilians to chemtrails) for all the bad they see. More often, weakly defined forces, such as capitalism or globalization, are pointed out. These seem only scapegoats to me. It does not matter if you base your policy on the assumption of socio-economic structures fully conditioning behaviour (Marxism) or on the one of human as perfectly-informed, fully-rational machines (macro-economics models). As long as these assumptions are wrong, your well-intentioned actions are doomed to failure.

Like it or not, the picture that emerges from rigorous research is that we are not noble savages, nor fallen angels. We are the product of blind evolutionary forces, just as any other living being. That may sound depressing. Still, I believe that the recent accumulation of serious knowledge on how human actually behave (and behaved) is invaluable. More than that, it is essential to build sustainable societies and institutions: something that may work with actual people, not only with an idealised picture of what we’d like to be.

(Un)sustainable Sweden

Wednesday, November 16th, 2016

The recently published 2016 Living Planet Report (LPR) edited by the WWF includes updated ecological footprint data bringing bad news to Sweden. The country is listed among the bad guys together with well-known polluters like the USA and Middle East oil-exporting countries. That, of course, in stark contrast with the common view of Sweden as a green, forest-covered country: a first-choice holiday destination for Europeans looking for natural scenery and wildlife. Being the ecological footprint a well known and scientifically recognised indicator, it cannot easily be dismissed as the last environmentalists’ paranoia. So where does this contrast come from?

Before answering that question, a few words are needed to explain what the LPR and the ecological footprint are. Although published by an environmental association, the LPR is not just another environmentalist pamphlet. The WWF has a serious history of collaboration with major scientists, and the LPR specifically includes the contributions of prestigious scientific institutions, such as the Zoological Society of London and the Stockholm Resilience Centre. The ecological footprint data themselves are not computed by the WWF but by an international think-tank called Global Footprint Network, which employs transparent and rigorous methods in their estimation. This makes the use of the ecological footprint indicator common in academic publications.

The ecological footprint indeed holds merits. It is designed as a consumption based indicator, which means that the environmental impact of a given good or service is attributed to the entity (individual, city, country, etc.) that benefits from its use, not to its producer. For instance, the impact of a mobile phone built in China but sold and used in Sweden will be attributed to the latter country not to China. This unlike other indicators CO2 emissions, for instance that point to the geographical area where the production process occurs. In synthesis, the ecological footprint estimates the overall burden placed on natural systems by the production, use and disposal of a given good or service and attributes it to the entity that actually used that good or service. Given sufficient data, it can be estimated at any scale: from the single individual to the whole planet.

Back to Sweden, the press release on the local WWF website explained the negative performance of the country as the result of a sustained consumption of imported goods, the need to heat large residential buildings, the prevailing fleet of big cars, and a high consumption of meat (I’d personally add the propensity to use disposable products even when easy alternatives exist). Unfortunately, disaggregated footprint data are not publicly available, which makes difficult to rigorously check these arguments. Still, data showing that they point out in the right direction exist. For instance, World Bank data show that Swedes imported goods for a total value of 137,625 millions of US dollars in 2015, which means over 14,000$ per habitant. As a comparison, consider that imports were valued 7200$ per person in the USA, 8600$ in France and 12,900$ in Germany. Similarly, international sales statistics report that cars sold in Sweden are among the largest and heaviest in Europe, with a correspondingly higher environmental impact from their production and use. Finally, meat consumption is indeed high in Sweden, although not at the world top, with science clearly showing that that lowering the consumption of meat and other animal products reduces environmental impact more than any other feasible action regarding food.

In short, Swedes really seem to consume too much to be sustainable, and possibly to hold bad consumption habits too. How does that fit with the fact that over two-thirds of the country territory are covered by forests or that the per capita CO2 emissions are lower than in most other European countries and less than one-third of the American ones? More generally, and in contrast with the picture above, Sweden holds one of the top position in Yale University’s Environmental Performance Index, which ranks the world countries based on more than 20 indicators of ecosystem vitality and environmental health.

The reliance on imported goods plays a role in explaining this discrepancy. Importing a high share of the consumed goods effectively means exporting environmental impact, like in the mobile phone example.This is considered in the ecological footprint analysis but not in other international statistics. However, the displacement of environmental impact is only part of the story. After all, Sweden is a large exporter of raw materials and manufactured goods too, with a corresponding impact on the country ecosystems. Although Sweden, as other advanced countries, has become more efficient in its use of natural resources in recent years, most of the merit for the good quality of the country environment actually derive from the fact that a large biocapacity reserve is still available in the country.

Biocapacity is an indicator that measures the supply of natural services, just as the ecological footprint measures the demand. It is estimated together with the ecological footprint and a comparison between the two allows to check whether a country could be sustainable should it rely on its territory alone (which, in practice, never happens because of the import/export of goods and services). Sweden has a biocapacity higher than its footprint and the resulting “reserve” explains how it is possible to have an exceedingly high level of consumption and a good environmental quality at the same time.


Ecological footprint and biocapacity in Sweden. Source: Global Footprint Network.

Unfortunately, what is possible for somebody is not necessarily possible for everyone. While the biocapacity available for the Swedes is about 11 gha/cap., the one for the average human is less than 2 gha/cap. This is not much a matter of ecological productivity, as tropical ecosystems are usually more productive than boreal ones, but of population density. Sweden has a population density of about 24 people per square kilometre, the world as a whole a density of 57 p./km2, most high-income countries vary between 93 p./km2 (Spain) and 503 p./km2 (The Netherlands). The biocapacity also vary for biological reasons (forests and wetlands are more productive than pastures and deserts) but the population density is the main factor explaining the differences among countries.

The world as a whole has experienced a per person biocapacity decline in the last 50 years. That not because the total biocapacity has actually decreased, although part of the productivity has shifted from natural systems to agricultural environments, but because human population has constantly grown in this period (and will continue to grow at least until the end of this century, following the last UN population prospects). The current ecological deficit hence seems to be more the product of the constant decline of the available per person biocapacity than of the increase in the average ecological footprint, which actually peaked in the mid 1970s and has remained approximatively stable afterwards.


World ecological footprint and biocapacity. Source: Global Footprint Network.

Sweden still holds some biocapacity reserve despite a high per capita footprint because of its low population density. Still, the population has increased by 30% since the 1960s and the per person biocapacity has reduced accordingly. As the population increase is projected to continue until the end of the century, the country may eventually reach the red area of the ecological deficit as well.

To conclude, Swedes live in a nice country because they are few, not because their behaviour is especially sustainable. Despite a relatively efficient resource use, their high level of consumption put them close to the top in terms of pressure on the global natural systems. The country remains green and pleasant partially because of the displacement of its environmental impact but mainly thanks to its low population density. Unfortunately, most of the times its inhabitants do not seem to realise it.