GWPF outlines a study by Erik Gartzke that discusses the links between global warming and war. Gartzke notes that post-war industrialisation is not only the putative cause of global warming but has also been associated with a steady decline in military strife. In fact, what evidence there is suggests that periods of global cooling are usually associated with the outbreak of hostiliities.
"Ironically," as Gartzke writes in the concluding sentence of his paper's abstract, "stagnating economic development in middle-income states caused by efforts to combat climate change could actually realize fears of climate-induced warfare." And thus he states in the concluding section of his paper that "we must add to the advantages of economic development that it appears to make countries more peaceful," and that we must therefore ask ourselves if environmental objectives should be "modified by the prospect that combating climate change could prolong the process of transition from warlike to peaceful polities."
I wonder if Lord Stern considered changes in levels of military conflict in his famous report.