LAUSR

To the Editor — In a recent Letter, Adams and colleagues1 argue that claims regarding climate–conflict links are overstated because of sampling bias. However, this conclusion rests on logical fallacies and conceptual misunderstanding. There is some sampling bias, but it does not have the claimed effect. Suggesting that a more representative literature would generate a lower estimate of climate–conflict links is a case of begging the question. It only makes sense if one already accepts the conclusion that the links are overstated. Otherwise it is possible that more representative cases might lead to stronger estimates. In fact, correcting sampling bias generally does tend to increase effect estimates2,3. The authors’ claim that the literature’s disproportionate focus on Africa undermines sustainable development and climate adaptation rests on the same fallacy. What if the links between climate and conflict are as strong as people think? It is far from obvious that acting as if they were not would somehow enhance development and adaptation. The authors offer no reasoning to support such a claim, and the notion that security and development are best addressed in concert is consistent with much political theory and practice4–6. Conceptually, the authors apply a curious kind of ‘piling on’ perspective in which each new study somehow ratchets up the consensus view of a country’s climate–conflict links, without regard to methods or findings. Consider the papers cited as examples of how selecting cases on the conflict variable exaggerates the link: each uses a case selection strategy rooted in the qualitative methods literature7. One, using a form of ‘crucial’ case study, finds no evidence of climate impacts on land-use conflicts in Mali, a region where climate–conflict links were particularly likely to be found8. The other, using a ‘structured, focused comparison’, investigates two regions in the Middle East with similar climate stress but different conflict outcomes and concludes that climate’s role as a conflict driver has been exaggerated9. It is hard to see how these papers mislead people into thinking climate–conflict links are stronger than they really are. Knowing that case selection is biased is useful, but not a reason to lower our estimate of the climate’s impact on conflict. ❐