I think Halvard would agree with all of this (I was a discussant on a previous version of this paper). His analysis simply points out problems with the Burke et al paper's model specification. Buhaug's is a modest contribution about model specification and appropriate data; it should be read as a response to an earlier paper rather than as a definitive statement about climate change and conflict. The headline is certainly provocative and unfortunate. However, he makes a useful corrective to overly simplistic causal claims, which typically dominate the popular literature on climate change and conflict. Yes, he could have been a little more modest with the title and with the conclusions, but then again, so could Burke and his colleagues. -Idean Salehyan

Cullen's comment should be pasted into every article that's written about this field of inquiry. We need a broader, and more sophisticated, understanding of different forms and dynamics of conflict.

I would add that statistical assessments, by their nature, lose a lot of detail and nuance. It seems to me that it's all about context. I understand that there is great interest in increasing our capacity to predict future events and outcomes, but that may prove not to be possible.

Very well put, Marc. My one point of disagreement would be on the state of current knowledge about the connection between economic shocks and the risk of internal war. Based on my own work and my (hopefully not too selective) reading of prior research, I would say that the evidence remains ambiguous on that important point.

Buhaug moved even further from the carefully hedged opinions expressed in his paper with an Aftenposten article titled "The Climate Wars Myth". It's hard to understand how tentative indications could firm up into definite conclusions without any intervening research.

History past and future will never be a science. The utility of statistics when applied to war is moot, and the discipline might easily be abused to produce evidence desired by either side in the debate. Correlation is treacherous and causation can never be established in situations of such complexity.

It doesn't take a Metternich or a Kissinger to conclude that climate change will constitute an increasingly powerful driver of conflict over the coming century even if the most optimistic projections are to be believed. The many (partly unrelated) water crises and exploding global demand for primary commodities such as energy and minerals will add to this pressure, as will the inherent instability resulting from the economic rise of China in a world where the USA has global alliances, a global network of bases and uncontested naval mastery.

An effective and enforceable climate change deal would require each signatory nation to act contrary to its individual interests in pursuit of the greater shared goal of a viable future. Such a feat of diplomacy has never previously been attempted or achieved. Each nation has every incentive to let the others make the effort — to 'defect' in game-theoretic jargon. None of this is intended to deter the pursuit of a treaty, only to illustrate the magnitude of the task and the incapacity of diplomatic arrangements to solve the problem.

It's important to bear in mind that there's no sign of the world converging on liberal democratic norms as predicted by Fukuyama. Only nuclear weapons add a dubious stability to affairs. The causes of conflict are more starkly obvious now than even in 1900 and a general crisis reminiscent of the 17th century does not seem far fetched.

While I've no reason to question Buhaug's integrity, his citation of Richard Tol — a Panglossian figure seemingly joined at the hip to Bjorn Lomborg — is cause for concern.