Again, on the matter of changes in the frequency and magnitudes of wars. From Harvard professor Steven Pinker (I added bolding):
War appears to be in decline. In the two-thirds of a century since the end of World War II, the great powers, and developed states in general, have rarely faced each other on the battlefield, a historically unprecedented state of affairs (Gaddis, 1989; Gat, 2006; Gleditsch, 2008; Holsti, 1986; Howard, 1991; Jervis, 1988; Keegan, 1993; Luard, 1988; Mueller, 1989, 2004, 2009; Payne, 2004; Ray, 1989); see Pinker (2011), chapter 5, for a review). Contrary to expert predictions, the United States and the Soviet Union did not launch World War III, nor have any of the great powers fought each other since the end of the Korean War in 1953. After a six-hundred year stretch in which Western European countries started two new wars a year, they haven’t started one since 1945. Nor have the forty or so richest nations anywhere in the world engaged each other in armed conflict.
In another pleasant surprise, since the end of the Cold War in 1989, wars of all kinds have declined throughout the world (Gleditsch, 2008; Goldstein, 2011; Human_Security_Centre, 2005; Human_Security_Report_Project, 2007, 2009, 2011; Lacina, Russett, & Gleditsch, 2005); see (Pinker, 2011), chapter 6, for a review). Wars between states have become extremely rare, and civil wars, after increasing in number from the 1960s through the 1990s, have declined in number. The worldwide rate of death from interstate and civil war combined has juddered downward as well, from almost 300 per 100,000 world population during World War II, to almost 30 during the Korean War, to the low teens during the era of the VietnamWar, to single digits in the 1970s and 1980s, to less than 1 in the 21st century.
