The biophysical phenomenon of terrestrial moisture recycling connects distant regions via the atmospheric branch of the water cycle. This process, whereby the land surface mediates evaporation to the atmosphere and the precipitation that falls downwind, is increasingly well-understood. However, recent studies highlight a need to consider an important and often missing dimension – the social. Here, we explore the social dynamics of three case study countries with strong terrestrial moisture recycling: Mongolia, Niger, and Bolivia. We first use the WAM-2layers moisture tracking scheme and ERA-Interim climate reanalysis, to calculate the evaporation sources for each country's precipitation, a.k.a. the precipitationshed. Second, we examine the social aspects of source and sink regions, using economic, food security, and land-use data. Third, we perform a literature review of relevant economic links, land-use policies, and land-use change for each country and its evaporation sources. The moisture-recycling analysis reveals that Mongolia, Niger, and Bolivia recycle 13, 9, and 18 % of their own moisture, respectively. Our analysis of social aspects suggests considerable heterogeneity in the social characteristics within each country relative to the societies in its corresponding evaporation sources. We synthesize our case studies and develop a set of three system archetypes that capture the core features of the moisture-recycling social–ecological systems (MRSESs): isolated, regional, and tele-coupled systems. Our key results are as follows: (a) geophysical tele-connections of atmospheric moisture are complemented by social tele-couplings forming feedback loops, and consequently, complex adaptive systems; (b) the heterogeneity of the social dynamics among our case studies renders broad generalization difficult and highlights the need for nuanced individual analysis; and, (c) there does not appear to be a single desirable or undesirable MRSES, with each archetype associated with benefits and disadvantages. This exploration of the social dimensions of moisture recycling is part of an extension of the emerging discipline of socio-hydrology and a suggestion for further exploration of new disciplines such as socio-meteorology or socio-climatology, within which the Earth system is considered as a coevolutionary social–ecological system.
Humanity is unequivocally leaving its mark on Earth, in terms
of changes to the land surface
The general process of water evaporating from the surface of the Earth,
traveling through the atmosphere as water vapor, and eventually falling out
as precipitation downwind is known as moisture recycling
Any research on moisture recycling that is either driven by anthropogenic
land-use change or is seeking to understand how changing moisture recycling
impacts land use has a social component. The range of social topics that
have been explored in the context of moisture recycling include natural
hazards and flooding
Social ecology, however, departs from the view that human and environmental
systems are separate and that social–ecological systems (SESs) are tightly
coupled complex adaptive systems. In its simplest form, the classic
social–ecological systems diagram
Here, we take inspiration from the SES type of thinking to address the social
dynamics of moisture recycling by posing the following questions:
How are moisture-recycling patterns interlinked with social dynamics? Are there dynamic social connections that link precipitation sinks and sources? What are the system architectures that create feedbacks among geophysical, ecological, and social drivers?
We want to be clear that our analysis includes both objective analysis of moisture recycling and social data as well as subjective assessment of ongoing policy and management activities related to land-use change. This blending of quantitative and qualitative, as well as objective and subjective, is at the heart of our approach to understanding the social dynamics of moisture recycling.
This work will be useful for three key reasons. First, the conceptual approach will provide Earth system scientists who study the atmospheric water cycle with the basics of how social systems (that are the sinks of upwind moisture recycling) are connected in many different ways back to the moisture sources. Second, this conceptual insight provides an entry point for more accurate modeling of the feedbacks that could affect moisture-recycling patterns (rather than only considering, e.g., geophysical phenomena). Third, this paper provides insights for resource managers, particularly land and water managers, who are searching for new leverage points within their dynamic social–ecological systems. Understanding where key feedbacks, bottlenecks, and potential cascades are located within a system can provide managers with better information about the consequences of direct or indirect intervention within their systems.
We argue that exploring the social dynamics of moisture recycling improves our understanding of Earth system dynamics by providing general insight into how humanity modifies the Earth system but also into the heterogeneity of moisture-recycling social–ecological systems.
We propose to develop a framework for moisture-recycling SESs, starting with the classical social–ecological systems concepts
Conceptual construction of moisture-recycling social ecological
system (MRSES) archetypes. A hypothetical, idealized social–ecological
system
Definitions of key terms used in this research.
To find regions that are both relevant to terrestrial moisture-recycling
dynamics, as well as (potentially) relevant to social dynamics, we use
regions selected from the work in
Based on these criteria, the selected case studies are Mongolia, Niger, and Bolivia. These three sink regions are distributed across three continents, providing separate moisture-recycling dynamics and distinct social systems while having a comparable spatial footprint (with subsequently comparable moisture-recycling source and sink footprints).
For each of these case studies, we identify (a) the discrete sources of
evaporation falling as precipitation within the case study, i.e., the
precipitationshed
We use an “offline Eulerian” moisture tracking scheme called the Water
Accounting Model-2layers, hereafter, WAM-2layers (for original model
configuration,
We use the backtracking feature of the WAM-2layers
Many approaches for precipitationshed boundary selection have been described
One approach to capturing the social dynamics of moisture recycling is to
characterize various social, economic, and other factors that are
biophysically relevant and that can provide insight into the dynamics among
the sources and sinks of moisture. In our analysis, we use land use based on
anthropogenic biomes data, i.e., anthromes
The child malnutrition data represent the number of malnourished children per
1000 under the age of 5 years and is available at the scale of countries
(e.g., Russia has a single value) as well as on a subnational scale (e.g.,
Sudan has many different values). The market influence data are a calculated
from a variety of other datasets and are a combination of (1) access to
markets (calculated using data on infrastructure, travel distance, and travel
costs to major cities) and (2) per capita GDP (for more on calculation, see
Note, the “source” results (presented in the social characteristics
figures, Figs.
Summary of metadata for anthromes, child malnutrition, and market influence data.
To complement the quantitative characterization of the precipitationsheds, we performed a literature review focused on each of the case study regions (i.e., Mongolia, Nigeria, and Bolivia), exploring potential dynamics that exist among the social, biophysical, and other aspects of the precipitationshed. The literature review is specifically intended to help reveal some of the qualitative, social interactions (e.g., land-use policies, regulatory interactions, economic interlinkages) that may be difficult to uncover in a purely quantitative analysis. We used the hypothetical MRSES concept diagram as a guiding heuristic for how to search for important dynamics.
For each case study, the general approach was to use the precipitationshed as the spatial boundary within which we evaluated the dominant processes governing land-use change and the types of dynamics among the sink region and the source regions. A blend of journal articles, non peer-reviewed literature, and web sources provided the key information for building the qualitative description of these social dynamics. The result of the case study analysis is a blend of quantitative and qualitative information, which combined to form a broad-based representation of the social dynamics of moisture recycling for each case study.
System dynamics models expose how different components of a system interact
with one another, and they can help reveal the relative importance of
different connections and interactions. We distilled the insights from the
three case studies into the creation of several MRSES archetypes. The
conceptual model presented in Fig.
In Mongolia, the precipitation source is located in the northern half of the
country and along its northwestern border (Fig.
Mongolia is predominantly classified as remote rangeland (
Mongolia's precipitationshed includes significant contributions from internal
recycling within Mongolia, as well as significant contributions from the East
Siberian taiga to the north, the steppes in Kazakhstan, and Xinjiang province
in northwestern China. Mongolia's land-use policy has had several distinct
phases of management in the recent past, with traditional management of
grasslands via customary nomadic herder institutions, then with the
Kazakhstan, to Mongolia's west, provides a significant amount of moisture
especially from its northern steppes, and from the Altai and Tien Shan. Following the collapse of the Soviet Union, Kazakhstan's livestock
population decreased significantly, with a concurrent reduction in grazing
land pressure
Mongolia case study including
In terms of politics, the ascendent Mongolian People's Party has strong ties
to Russia's Vladimir Putin, suggesting that political and diplomatic levers
of power may flow not through adjacent China but rather north to Russia
Niger case study including
To summarize, Kazakhstan's abandonment of former grazing land, the low level of land-use change in the East Siberian taiga, and the isolation of the Altai and Tien Shan regions suggest relatively low social connectivity from source to sink. Likewise, given the fact that Mongolian institutions are stronger (than, e.g., in Kazakhstan and in Xinjiang) and that the departure from historic land use and land management is more pronounced in Mongolian grasslands, we suggest that the social connections are strongest within Mongolia itself, leading to a somewhat isolated state of precipitationshed social connectivity.
In Niger, the precipitation source is concentrated along the southern border
(Fig.
Land use in Niger is predominantly “wild barrens”, given that much of its land surface is in the Sahara. Among the populated anthromes, Niger is equally distributed among rainfed croplands, rangelands, and inhabited (i.e., very low population density) barren lands. Residential rainfed crops are a dominant anthrome type among Niger's moisture sources, along with some rangelands and woodlands. Niger's hunger and wealth characteristics are different from its source countries with the mean values of USD 49.20 per capita market influence and 40.2 % child malnutrition, barely within the standard deviation of the societies in its evaporation sources. The average market influence among Niger's sources is USD 4081, with a very wide standard deviation ranging from nearly USD 0 to more than USD 11 000. Likewise, the mean child malnutrition is 23.8 % with a standard deviation from a high of 40 % to a low of around 7.5 %.
Within Niger, land-use change over the last several decades has seen
increases in cropland cover (where possible) with corresponding decreases in
fallow land
Directly to the south, Nigeria provides a considerable fraction of Niger's
rainfall and has a uniform, national land-use policy (i.e., the Land Use
Act), which essentially grants the authority of land ownership to the
governor of each Nigerian state
Chad, located to the east of Niger, provides around 6 % of moisture but
suffers from chronic poverty. Reliance on agriculture or livestock rearing
provides 80 % of Chadian employment, but open-access policies for land
have led to overgrazing and inadequate management has led to deforestation
and desertification around dense population centers. These dynamics
contribute to an uncertain and rapidly changing land-use regime in Chad
(
Bolivia case study including
Niger's primary trading partners are France, Thailand, Malaysia, and China, with Nigeria the only notable regional trade partner. France is the destination and origin of more than 30 % of both exports and imports. Regionally, Nigeria is the destination of 9.5 % of Niger's total export volume, primarily in the form of refined petroleum. Similarly, Niger receives about 5.8 % of its total imports from Nigeria, primarily in the form of cement, electricity, and tobacco. Niger, however, represents a tiny trade partner for Nigeria, providing only 0.25 % of Nigerian imports and 0.18 % of Nigerian exports. Beyond this, Chad and Sudan are very poorly integrated in terms of total trade volume with Niger and Nigeria. Thus, the countries in this region appear to be much more economically tied to countries outside the region than within the region. Overall, this suggests limited regional economic integration.
To conclude, the rapid land-use change taking place in many parts of Niger's
precipitationshed suggests there is a high potential for change in moisture
recycling driven by social–ecological processes. The ability to influence one
another's land use, and subsequently moisture recycling, is thus possible.
However, active coordination among key sources in Niger's precipitationshed
is relatively low. Some international institutions, such as the International
Water Management Institute's Water Land and Ecosystems programme, enable some
trans-boundary policy coordination on key water and ecosystem issues
In Bolivia, the source of the precipitation is distributed across the
country, with a slight concentration in the north
(Fig.
Bolivia's anthromes are more than 50 % rangelands and a little more than 25 % woodland, i.e., the Amazon. The key source areas are the Amazon in Brazil and Peru, but broadly speaking, Bolivia's precipitationshed includes a high fraction of rangelands (about 50 %). Rainfed croplands comprise much of what remains (about 10 %). Bolivia is characterized by relatively low child malnutrition (mean of 7.2 %, with a standard deviation ranging from 5 to 10 %) and market influence of USD 341, ranging from just above 0 to more than USD 800. This is not very wealthy compared to some regions, but it is considerably better off than other regions' chid malnutrition (especially that of the Niger case study). Bolivia's sources of moisture are characterized by societies with higher mean malnutrition (14 %) and higher wealth (USD 506), though the standard deviation exceeds all of Bolivia's values. This means that in terms of the standard deviation, Bolivia's social characteristics are well within the range of the societies in its precipitationshed.
Bolivia's precipitationshed includes key contributions from within Bolivia
itself, from Brazil, and from Peru. The dominant land uses throughout the key
source regions are rangelands and forests. The strength of land-use
management, in terms of governance effectiveness varies among these three
nations, as does the level of land-use change, ranging from well-developed
land-use methods (such as in Brazil) to much lower impact, though with high
potential (as in Peru). Bolivia itself generates 18 % of its own
rainfall, primarily from tropical forests, the Pantanal wetland, and
rangelands. Historically, Bolivia's government has had a strong control on
the protection of forests from change, such as the first “debt-for-nature swap”
in 1987
In adjacent Peru, the key forested areas that could change, and thus lead to
changes in moisture recycling, are very difficult to access, yet as
population migration to the Peruvian Amazon is high, the current rate of
deforestation is steadily increasing
Archetypes of moisture-recycling social ecological system (MRSES), with blue corresponding to “isolated”, red to “regional”, and green to “tele-coupled”.
Land-use policy in Brazil is quite strong, at least on paper. However, the
regulatory environment is inconsistent, and the enforcement strongly depends
on which political party is in power
The quality and strength of land-use policy within these three countries is
strongly tied to both national-level policy, as well as participation in
international land-use management efforts (e.g., REDD
Bolivia's dominant exports are fossil fuels (45 %) and minerals (zinc,
precious metals, lead, gold, etc., nearly 30 %)
The shared issues of deforestation in Peru, Brazil, and Bolivia, as well as
strong legacies of deforestation policy in Bolivia and Brazil, suggest a
relatively strong institutional capacity for managing change. Likewise, the
economic connection, albeit in the form of natural gas pipelines connecting
Bolivia to Brazil, suggests a reliable economic connection
Based on the results from case study analysis, we see three basic patterns of
social dynamics in moisture-recycling systems: (1) an isolated system
archetype, dominated by internal processes; (2) a regional archetype linking
adjacent countries; and, (3) a tele-coupled archetype that links
precipitation sink regions with regions outside the precipitationshed
boundaries (Fig.
The core structure of each archetype is empirically grounded, given that it
is well-understood that land-use change directly affects evaporation, with
increased vegetation typically increasing evaporation and decreased
vegetation typically decreasing evaporation (
How well people are doing (e.g., whether they are hungry or not) will inform
the decisions they make about further modifications to the landscape
The “isolated” archetype is the simplest of the proposed MRSESs. In terms of
social dynamics actively driving change in the precipitationshed, Mongolia is
isolated. In the isolated archetype, we draw attention to the fact that
there are few connections or feedbacks beyond local government or with
other regional actors (Fig.
As the social connections between different sources and sinks become more
numerous, regional interactions emerge (Fig.
To generalize, as the importance of internal moisture recycling decreases,
the activities of key source regions ought to be considered. Where the
rule of law is present, changes in regional evaporation could be related to
government regulations or policies that serve to influence how land-use
change unfolds. However, in more lawless regions where governance and
institutions are absent or corrupt, large-scale land-use change is typically
driven by national or international corporate actors
The third MRSES is “tele-coupled”, and this structure draws attention to
the spatially disconnected, i.e., tele-coupled, actors that can influence the
social connections in the central, regional, or tele-coupled feedbacks
(Fig.
Concept of MRSES in relation to other concepts pertinent to human–water system research along the axes of spatial scale and feedback complexity considered and in terms of water flows considered. Blue water refers to liquid water in rivers, lakes, and aquifers, whereas green water here refers to terrestrial evaporation and moisture flows.
Our analysis ends up with three archetypes that are idealized in structure
and interaction. However, there are situations where certain aspects of the
archetypes as they are represented may actually be at odds with one another.
For example, in Fig.
The archetypes themselves are also idealized in that they are depicted as separate, distinct systems. Yet, in reality, they are likely to exist along a spectrum from isolated to tele-coupled. Thus, for example, in moving from isolated to regional, the MRSES might first integrate the regional moisture-recycling components and then begin incorporating regional markets, regional policy, etc. The spectrum of the MRSES from isolated to tele-coupled is not meant to convey any sort of desirability one way or another; each has benefits and disadvantages. For example, in an isolated case with intense contributions from nearby regions, there is a greater concentration of risk from accelerating feedbacks, such as local forest clearing reducing evaporative flow to the atmosphere, thereby leading to a positive feedback of less moisture available for local rainfall and subsequent impacts on vegetation. Conversely, diffuse contribution suggests less risk from a single location but concomitantly less possibility to manage or influence land use.
In this work we only examine three case study regions that roughly correspond to three archetypes, yet we are able to provide some guidance for the construction of additional archetypes using our method. First, it is important to note the number of countries providing significant evaporation contribution (i.e., a few or many), in which social processes are driving rapid land-use change. Second, the precipitationshed can have low or high connectivity to global markets. When combined, these two classifications would make four archetypes. However, we suggest only three archetypes, since global market connectivity will make a MRSES tele-coupled regardless of whether there is one country where social processes are important (e.g., Mongolia) or many countries (e.g., Niger). In other words, once a country crosses the threshold from being disconnected to connected to global markets, it moves inexorably from being either isolated or regional to tele-coupled. Furthermore, this dynamic is unlikely to be reversed given the momentum and increasing networked complexity of global markets and institutions, with notable exceptions, such as post-Soviet nations.
The proposed MRSES framework offers a new conceptual lense to delineate
system boundaries in regions where moisture recycling and human land-use
decisions are substantial in comparison to other dynamics at play. This
complements the various frameworks, theories, and mental models that have been
developed for understanding human–water systems in terms of spatial scale,
complexity of dynamics, and part of the water cycle considered
(Fig.
As illustrated in Fig.
Thus, the MRSES concept, while lacking the cross-sectoral or holistic perspective
in comparison to nexus or world system approaches, fills a conceptual gap by
accounting for social feedbacks and atmospheric moisture flows with a consideration of local to regional scale socioeconomic dynamics and policy
processes. Potentially, MRSES could be woven into large-scale hydrological
modeling or form part of a hydro-economic model, in addition to other human
interference such as irrigation, inter-basin transfer, and virtual water
The MRSES archetypes we propose all exhibit some complexity and increase in
complexity when moving from isolated to tele-coupled. Complexity indicates
the potential for surprises induced by feedbacks
A notable feature is the role of tele-coupled, spatially disconnected actors
for driving change in the precipitationshed. For example, the change in the
spatial distribution of Amazonian deforestation, i.e., in Peru and Bolivia, is
apparently driven by palm oil and soya cultivation in Peru and Bolivia
Additionally, the relationships we identified as potentially existing in the system underline the reality that the system has different kinds of leverage points. For example, in the feedback loop of the isolated archetype, where policy influence and moisture recycling are tightly interconnected, there is potential for faster change but also for more immediate intervention. Conversely, the geophysically separate, socially tele-coupled drivers of land-use change can influence a region's rainfall, while the recipients of that rain have much less of an ability to influence those tele-coupled drivers of change. Moreover, the tele-coupled international actors have the potential to influence both economic policy in the sink region as well as apply market pressure to societies that are regulating rainfall. All the while these tele-coupled actors experience very little feedback from the moisture-recycling system, aside from indirect changes to, e.g., commodity crops. All of these different dynamics suggest that a portfolio of governance strategies will be necessary to address different kinds of challenges (see more on institutional challenges in Keys et al., 2017).
Though our analysis of the relationship between moisture recycling, wealth,
and hunger has been simplified (e.g., Figs.
Second, as MRSESs expand to include more than one country, the potential for
some parts of society within the MRSESs to have more control over others may
become more complex, and furthermore, the political power balance among
nations becomes more important. In the Bolivia and Niger cases, the ability of
precipitationshed nations to drive change (e.g., Brazil for Bolivia and
Nigeria for Niger) begins to matter. Moreover, in tele-coupled systems,
international and non-state actors can begin driving significant terrestrial
moisture-recycling change, for example by interference (or control) of
land-use change on commodity prices. This sort of relationship has been noted
in other work as well, such as the ability of Chinese land-use decisions to
impact North Korean precipitation
Other work has suggested the importance of existing institutions for
governing moisture recycling
As we move forward as a scientific community, and potentially if the concept of precipitationshed gains traction in the practitioner community, it will become increasingly important to have tools that allow us to answer questions related to justice, equity, and livelihoods. Interdisciplinary scientists, especially those trained in the natural sciences, ought to learn to recognize the potential pitfalls of a limited scientific worldview. For example, natural scientists are often “positivist”, meaning they assume that a meaningful assertion ought to be scientifically verifiable and provable logically or mathematically. This is not the worldview of much of the social science community, let alone in the practitioner community or the broader public. An awareness of the diversity of scientific worldviews is critical for successfully addressing inherently value-based questions (i.e., normative questions). At a core level introspection is prerequisite for evaluating the questions being asked and how those questions are posed.
Furthermore the hydrological description of sources and sinks of atmospheric moisture is inherently charged with social import. For example, demonstrating that Brazil is very important for Bolivia's rainfall potentially adds a matter for negotiation between the two countries, with all that entails, especially in terms of responsibility and power. Recognition of these implications is critical for natural scientists to become better interdisciplinary scholars as well as responsible and conscientious members of society.
Evaporation can be or is actively changed through, e.g., policies, cultural pressures, economic incentives, legal regimes, and treaties in social systems, and it is limited by, e.g., water availability, edaphic suitability, and energy limitation in the biophysical system. The type and nature of this manageable or managed evaporation is important for understanding the management space. Thus, future work could undoubtedly extend and perhaps substantiate social linkages by first identifying and quantifying managed evaporation within different administrative zones. Likewise, specific policies could be linked to these administrative zones, which could explicitly link legal, policy, and on-the-ground management efforts with particular flows of evaporation and subsequently moisture recycling.
The analysis of moisture-recycling relationships, market influence, and child
malnutrition suggests a reasonable basis for exploring the social dynamics of
moisture recycling more broadly. Existing work has examined the import and
export of atmospheric moisture among nations (
Here, for the first time, we systematically explored the social dynamics of moisture recycling. We provide an approach, based on multiple quantitative and qualitative methods, for revealing the structure of moisture-recycling social–ecological systems (MRSESs). We demonstrate this approach using three case studies – Mongolia, Niger, and Bolivia – and describe the social dynamics that have the potential to impact evaporation and subsequently moisture recycling. The key conclusion is that quantitative analysis is not enough to determine which drivers are most important for the social dynamics of moisture-recycling systems. A qualitative understanding, strengthened by a familiarity with relevant land-use change drivers, is critical to unraveling whether a region has social dynamics that are isolated, regional, or tele-coupled. Finally, we argue that Earth system scientists ought to explicitly consider the social dynamics of their work to more holistically represent reality as well as to better engage in interdisciplinary science.
All data used in this paper are available from other work.
The moisture-recycling data for Mongolia, Niger, and Bolivia are available
here:
Both authors contributed to conceptual development, data analysis, and manuscript preparation.
The authors declare that they have no conflict of interest.
This article is part of the special issue “Social dynamics and planetary boundaries in Earth system modelling”. It is not associated with a conference.
We appreciate the encouragement of many academic peers to work outside our comfort zone, especially Line Gordon, Thorsten Blenckner, and Sarah Cornell. We also thank the extraordinary and thoughtful comments from four anonymous peer reviewers as well as Paul Dirmeyer and Murugesu Sivapalan. Their critique and suggestions made this work much more substantial and considered.Edited by: Murugesu Sivapalan Reviewed by: Paul Dirmeyer and four anonymous referees