The present, and future, effects of climate change could be some of the greatest obstacles in reaching pathways of sustainability. Climate change is a global driver of change of an unprecedented scale (see our previous post on the role it could have in producing linked global crises). Already there are strong links to regional crop failures, changes in fish catches and human migration patterns. A critical, and controversial, question is how global climate change can affect the risk of conflict (or peacefulness, if you will) in human societies? Is it possible that the consequences of climate change can push societies, already close to a "conflict threshold", over the brink and into armed conflict?
Some historians have argued, using historical and anecdotal data, that global climatic phenomena such as ENSO have driven patterns of civil conflict in the past. On the other hand, quantitative tests of this have been few and produced very inconclusive results. For example, long-term correlations between climatic trends and frequency of civil conflicts within a given region of the world have been weak. These tests have also been confounded by social and political variables, that seem better at explaining the risk of civil conflict as opposed to climate. In other studies, local proxies of climate change have been used (e.g. rainfall or temperature shocks) to assess correlations with local civil conflicts. These group of studies have received critique because local weather patterns are a bad proxy for global climate.
A new study, by a team from Columbia and Princeton universities, United States, and published in Nature this week (24 August) circumvents many of the above weaknesses by correlating global El Nino patterns (in other words, no local or regional proxies of climate change) to more than 230 civil conflicts that took place globally between 1950 and 2004. The findings are causing quite a stir. The El Niño cycle, which periodically warms up the Pacific Ocean and affects weather patterns in many countries, has influenced 21% of civil wars around the world and almost 30% in the countries where El Niño has a high impact — the tropical parts of Africa, Asia-Pacific and South America. Although the study does not go into the mechanisms behind this relationship, i.e. why why or how changing weather (due to climate trends) affects outbreaks of violence, El Niño is known to be correlated with crop losses, natural disasters and the spread of infectious diseases. So the authors suggest that income inequality, declining employment, governments incapable of enforcing law, or even the physiological effects of heat could tip volatile situations over the edge. As the paper reads:
"ENSO has a proximate influence on a variety of climatological variables, each of which may plausibly influence how conflict-prone a society is. Precipitation, temperature, sunlight, humidity and ecological extremes can adversely influence both agrarian, and non-agrarian economies. In addition, ENSO variations affect natural disasters, such as tropical cyclones, and trigger disease outbreaks. All of these have adverse economic effects, such as loss of income or increasing food prices, and it is thought that economic shocks can generate civil conflict through a variety of pathways. Furthermore, altered environmental conditions stress the human psyche, sometimes leading to aggressive behaviour. We hypothesize that El Niño can simultaneously lead to any of these adverse economic and psychological effects, increasing the likelihood of conflict. Furthermore, the influence of ENSO may exceed the sum influence of these individual pathways because it is a global-scale process that generates simultaneous and correlated conditions around the world. This is possible if non-local processes, such as increasing global commodity prices or conflict contagion, strongly influence local conflict risk. Future work will examine the relative importance of these various mechanisms."