Tuesday, September 14, 2010

The Climate Wars War

Gwen Dyer's 2008 book Climate Wars (discussed earlier on the blog both here and here) is the best known of a series of works analyzing the idea that climate change might be a trigger for social disorder, population migration and conflict. Among the others are 2003 report for the Pentagon on the national security implications of climate change; the Stern review on the economics of climate change, prepared for the UK government in 2006; and the United Nations’ post-conflict environmental assessment of Sudan in 2007, which suggested that climate change was an aggravating factor in the Darfur conflict.

But is there real proof of a link between climate change and civil war? It turns out, according to Nature News, that there is an academic war over the potential existence of such real wars.
In research published this week, he (Halvard Buhaug, a political scientist with the Peace Research Institute Oslo) finds almost no correlation between climate change indicators, such as temperature and rainfall variability, and the frequency of civil wars over the past 50 years in sub-Saharan Africa — arguably the part of the world that is socially and environmentally most vulnerable to climate change. “The primary causes of civil war are political, not environmental,” says Buhaug.

The analysis challenges a study published last year by Marshall Burke, an economist at the University of California, Berkeley, and colleagues, who reported a strong historical relationship between temperature and the incidence of civil war. They found that the likelihood of armed conflict across the continent rose by some 50% in unusually warm years between 1981 and 2002. Neither Burke nor Buhaug is giving any ground; each challenges the other’s definition of ‘civil war’ and choice of climate data sets. Given the many causes of unrest, it is not surprising that a meaningful correlation with climate is hard to pin down, says Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research in Germany.

1. Buhaug, h. Proc. Natl Acad. Sci. USA doi:10.1073/
pnas.1005739107 (2010).
2. Burke, M. B. et al. Proc. Natl Acad. Sci. USA 106,
20670–20674 (2009).

Three important points are worth noting. First, there is a substantial tradition of research dealing with the link between environmental scarcity and violence. The focus on climate change as the driver for particular types of environmental scarcity (e.g., arable land, potable water, etc.) is merely a specific twist on that earlier research.

Second, that research has also been the subject of vigorous debate. However, there are some points which emerge from the cacophony: 1) there is a relationship between environmental scarcity and violence, but the relationship is much more subtle and indirect than most people think; and 2) in contrast to the bulk of the literature which interpret their results through the lens of a particular philosophical orientation, there exist a few analytic gems such as Colin Kahl's States, Scarcity, and Civil Strife in the Developing World (reviewed here).

Third, and perhaps most significantly, both Buhaug and Burke buttress their arguments with statistical evidence gleaned from studies of a variety of historical cases. The underlying premise is that the past is prologue to the future. However, to the extent that one sees climate change as potentially involving a dramatic tipping point, that premise may not be valid.


  1. The proper question to ask is "Is there real proof of a link between "climate change" aka global warming and carbon dioxide?" Answer, No.

  2. That's a fine question. The answer, however, doesn't provide much nutrition. Statements of conclusion without evidence are opinion -- you're entitled to them, but don't expect anyone else to be persuaded.