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The paper focuses on the nexus between climate change and armed conflicts with an empirical analysis based on a panel of georeferenced cells for the African continent between and Our econometric approach addresses unobservable heterogeneity in predicting the probability of violent events and the persistency of conflicting behaviour over time. The proposed strategy also accounts for both changes in climatic conditions and spatial dynamics.
The two main findings carry policy-relevant implications. First, changes in climatic conditions influence the probability of conflicts over large spatial ranges, thus suggesting that the design of adaptation policies to reduce climate vulnerability should account for multiple spatial interrelations. Second, the persistency of violence calls for planning adaptation strategies for climate resilience jointly designed with measures in support of peacekeeping. The deterioration of living conditions due to climate change is the trigger of a vicious cycle that imperils individual well-being and, ultimately, social order.
Violent events are hard to predict and difficult to counter as they propagate in unforeseeable directions. One major concern is the prospect of conflicts in regions of the world that are vulnerable to climate events and, also, prone to social instability. The goal of the present paper is to develop an empirical strategy that allows addressing unobservable sources of heterogeneity in the climate-conflict nexus. This allows better disclosing temporal and spatial mechanisms that are relevant for integrating climate adaptation policies with peacekeeping actions to fruitfully exploit potential ancillary benefits or to mitigate negative side-effects.
We focus on Africa, a continent that is home to some of the most conflict-ridden regions in the world according to Croicu and Sundberg Empirical evidence suggests a correlation between changes in temperature and rainfall patterns, that have the effect of worsening living conditions of African populations in vulnerable areas, and the breakout of violence Dell et al.
The acceleration of climate change in such a precarious context exacerbates tensions and gives way to repeated armed conflicts as well as massive migratory movements Daccache et al. At the general level, changes in weather conditions present both direct and indirect impacts on human beings Buhaug, ; Burke et al. Direct effects can be envisaged in the increase of violent behaviours associated to higher temperatures given that people become more nervous, or in the conflicts for access to water when extreme drought conditions directly harm human livelihood.
Indirect effects are explained by the impacts on anthropogenic activities as in the case of agriculture, or reduction in land fertility or diseases diffusion, which in turns foster competition over scarce resources and at the end cause battles and wars. In the context of developing countries, agriculture is unquestionably the sector most exposed to climate variability Raleigh et al. The occurrence of climate-related shocks increases the risk of armed-conflict outbreak under certain socio-economic conditions, as for instance a high degree of ethnic fractionalisation Schleussner et al.
A recent and comprehensive literature review by Koubi points out that the debate on whether changes in climatic conditions systematically increases risk of conflict or magnitude is still open. A contentious, and to some extent unexplored, issue is whether location-specific conditions amplify the effects of changing weather conditions. Scholars concur that resilient communities experience lower risks of violence in certain climate conditions Buhaug, ; Burke et al.
The present paper adds to the foregoing debate a novel methodology and empirical evidence on the existence and magnitude of the climate-conflict nexus in Africa with three contributions. First, we propose an econometric approach that overcomes some shortcomings of prior research. Empirical analysis of climate-induced conflicts based on large-N quantitative analysis Busby et al. Depending on the measure, empirical studies yield contradictory findings even when the same explanatory variables are used.
This is because socio-economic, territorial and climate conditions interact in non-linear ways and minor variations in one, or more, of the attendant characteristics can lead to extremely different outcomes. One interesting contribution in this direction is the linear equations in two variables class 10 notes pdf analysis carried by Mack et al. In order to control for differences in structural characteristics i.
Along with this intuition on the role of structural features in shaping the transition from peace to war, we propose a zero-inflated negative binomial ZINB regression model to estimate the influence of local climate conditions and other geographical and socio-economic features both on structural zeros affecting the probability of conflicts and on the magnitude of violence. This empirical framework better accounts for the propensity of violence in small areas even if they have not experienced any conflicts in the past.
In turn, this has the potential of informing policy, both in terms of adaptation strategies as well as peacekeeping actions, by focusing not only on areas that are commonly known as prone to climate-related social disruptions but, also, on peaceful places that would be at risk of violence if climatic conditions worsen. Second, we explore non-linear relationships between the vulnerability of the agricultural sector to climate-related events and the magnitude of violent conflicts.
The connection between climate and natural resource environment is far from trivial because the vulnerability of a territory depends on intervening context-specific features such as the degree of mechanisation in agricultural activities, the quality and quantity of chemical products used or the degree of diffusion of irrigation systems Bates et al. The seminal study by Harari and Linear equations in two variables class 10 notes pdf Ferrara finds a linear positive correlation between short-term climate shocks during the growing season and the probability of conflict breakouts.
Likewise, Almer et al. We build on and extend the above by: i measuring climate shocks determined by weather conditions with diversified time scales; ii explicitly accounting for local geographical features—as suggested by Anselin —by distinguishing the impact associated to the direction linear equations in two variables class 10 notes pdf to the magnitude of weather variations Papaioannou, Our results suggest that the pressure on food availability related to water scarcity increases the number of conflicts only if the drought condition has persisted at least for 3 years prior.
On the other hand, excess in rainfalls triggers larger and immediate reactions. This leads us to suggest that such non-linearity should be carefully accounted for when punctual actions for improving the resilience of the agricultural sector are planned. Third, we what does bad stand for in medical terms the role of cross-area spillovers on local conflicts.
In particular, we estimate for each cell the impact on the magnitude of violence of changes in climate conditions, agricultural yield, and socio-economic features such as income per capita, income inequality and demographic change in neighbouring cells. In so doing, we capture indirect conflict pathways that are difficult to identify in the absence of large-N scale spatial data. The main findings are that long-term growth in temperature and precipitations in linear equations in two variables class 10 notes pdf surrounding areas leads to an increase of violent events within the cell by 4—5 times, with a threshold distance of up to km radius.
On the opposite, short-term events as floods trigger conflicts only at a narrow local scale with negligible geographical spillovers. This points to why wont my phone connect to cellular network broader approach towards the design of adaptation strategies, namely by accounting for potential ancillary benefits due to the propagation over space of the positive effects of higher climate resilience.
The rest of the paper is structured as follows. In Sect. The empirical analysis of the nexus between climate change and armed conflicts has grown remarkably over the last decade Ide, Three types of studies dominate this strand. A second group of studies with greater spatial coverage uses artificially designed geographical scale based on administrative borders counties or countriescells with equal non causal relationship dimension Almer et al.
The third and more recent literature strand resorts to a multi-method approach that combines statistical inference with qualitative comparative analysis and case studies No greek no bb meaning et al. Each of the foregoing approaches carries benefits and shortcomings, and the selection of one or another ultimately depends on the research questions.
Since the present paper deals with the impact of long-term changes in climate conditions and the role of geographical spillovers, we opt for the large-N scale approach based on an artificial grid. The rationale for this spatial scale is threefold. The first reason is the spatial availability of data on gross per-capita income at the level of individual cells. Third, this allows linear equations in two variables class 10 notes pdf with linear equations in two variables class 10 notes pdf balanced panel that covers the whole African continent, thus avoiding sample selection bias and allowing for a dynamic assessment.
Footnote 1 This is a standard approach in the analysis of the climate-conflict nexus as the inter-states conflicts usually pertain to tensions regarding transboundary waters, where climate stress impacts are indistinctly related to property rights regimes GCA, Given the nature of the dependent variable, we implement a dynamic spatial regression model for count data that accounts jointly for the drivers of a conflict outbreak and the magnitude of violence.
Count data regression analyses are characterized by discrete response variables with a distribution that places probability mass at positive integer values. Our response, in particular, exhibits overdispersion and an excess number of zeros, which leads us to use a what kills mealybugs in the soil negative binomial ZINB count model.
Based on the canonical log link for the negative binomial component, the regression equation for the conditional mean can be written as:. In what follows we refer to Eqs. Notice that the occurrence of zero outcomes under the ZINB model rests on two premises. First, some cells will not experience conflicts for structural reasons, for instance because the corresponding territory is covered by desert or by water that prevents anthropic activities.
On the other hand, other cells may experience or not violent breakouts depending on factors common symptoms of visual impairment are best captured by additional explanatory variables. Moreover, relative to logistic regression, the ZINB specification allows assessing the intensity of the phenomenon, rather i cant stop coughing in spanish merely its occurrence Mack et al.
Together with unobservable heterogeneity due to structural features, also spatial dynamics might influence our response variable. Notice that different types of interaction effects can explain why an observation at a specific location may depend on observations at other locations Elhorst, First, due what are the gender symbols on bumble endogenous interaction effects, the response variable Y of a particular unit depends on the response variable of neighbouring units.
Second, due to exogenous interaction effects, the response variable of a particular unit depends on the explanatory variables X of neighbouring units. A third mechanism concerns interaction effects among the error terms, for instance in presence of spatial autocorrelation between the determinants of the response variable omitted from the model. These effects can be included in a spatial econometric model by means of a non-negative matrix W that describes the spatial configuration of the units in the sample.
Thus, in a normal setting a full general model for panel data with all types of interaction effects can be written as:. Turning what does imap mean in email the inclusion of spatial interaction effects in a regression model for count data, as for instance the ZINB in Eqs. Thus, accounting for the spatial structure in the unexplained part of the dependent variable is not as straightforward as in the continuous case.
In fact, spatial error models can be defined also for count data by introducing in the regression equation spatial random effects following for instance the conditional autoregressive scheme Besag, ; Pettitt et al. Further, the introduction of endogenous interaction effects is controversial in classical count data models.
This is because there is no direct functional relationship between the regressors and the dependent variable but, rather, a relationship between the regressors and the conditional expectation of the response. One strategy to overcome this issue is the auto-Poisson model proposed by Besagwhich includes the spatially lagged dependent variable in why are high school relationships pointless intensity equation of a Poisson regression model, but it suffers from various limitations.
Another option is to include the spatially lagged dependent variable into the intensity equation using an exponential spatial autoregressive coefficient Beger, Yet another possibility is the addition of the spatially lagged conditional expectation—rather than the spatially lagged dependent variable—to the intensity equation Lambert et al. However, none of these different proposals have found broad application.
In contrast, the introduction of exogenous interaction effects in regression models for count data is straightforward and raises no particular issues since spatially lagged regressors can be computed before the actual regression is performed and treated in the same way as the non-spatial ones Glaser, In particular, introducing exogenous spatial interaction effects in Eqs. Another relevant issue in spatial econometrics concerns the choice of the spatial weight matrix W.
Three elements are worthy of attention: i the method for computing distances between geographical units; ii the adoption of a normalisation procedure; iii the choice of a cut-off point. This procedure, unlike row normalization, leads to a weight matrix that is symmetric, thus still allowing for an economic interpretation of distances, and that maintains the mutual proportions between the elements of W Elhorst, With respect to the third issue, we explore the behaviour of different cut-offs calculated by combining the pure inverse distance with the queen contiguity approach.
Since all cells in our dataset have the same spatial dimension, this is the only way to account for cut-offs that include all the cells belonging to the buffer whose radius is the cut-off measure. This brings to select 11 ideal cut-offs that include all cells whose centroid is in the area with radius of,,, km, respectively hereafter referred to from W1 to W For a discussion on the cut-off choices in the econometric estimation see Sect.
The key explanatory variables of our analysis cover four dimensions. The list of variables is provided in Table 1 while further details on the way the indicators have been computed are provided as Supplementary material. Footnote 3. We gather monthly data for Africa at 0. The decades — are excluded from the econometric estimation and serve as a benchmark for computing long-term changes in climatic conditions. Starting from monthly information, we compute the long-term trend of variation for precipitation and temperature by calculating for each year the average variation of the difference between the yearly change in the climate recorded in a given month from onwards and that registered in the same month of the previous year and, the corresponding average variations of that month recorded in the base period — Third, according to the classification system defined in McKee et al.
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