I went into this somewhat in the other thread, but: Pick a major event, and you'll find it's had a pretty large impact throughout most of sf's history... Even in the early pulp days, when it was mostly just adaptations of adventure stories to using scientific jargon, you'd still see more and more of that creeping in, though it was often the startling scientific discoveries that were to have long-term effects, rather than contemporary social or political events -- things like the confirmations for relativity, the splitting of the atom, that sort of thing. In England and the Continent, where sf had remained more literary, the social issues were closer to the surface, generally speaking: especially with such things as Bulwer's The Coming Race; though America had its share of writers who delved into that as well, such as London with The Iron Heel.
By the end of the Gernsback era, the world around had become a major influence on American sf once again, especially as Europe geared toward another World War. A lot of sf explored the fallout of the First World War, and the causes and possible outcomes of the looming Second. But even during the 1930s, there were some of the same concerns we've seen in science fiction since, such as ecological concerns, addressed in several stories such as "The Man Who Awoke," by Laurence Manning; growing concerns about Nazism, Fascism, the lack of American willingness to get involved in the conflict (or the concern that we would); Heinlein addressed current political philosophies such as Technocracy, for instance; and the threat of atomic weaponry began to become a major concern of many, rather than an element in stories by a few.
In America, the post-war years saw McCarthyism, and American sf was very concerned with that movement and its threats to a stable democracy; while just about all sf writers were concerned at one time or another during those years with various Doomsday scenarios, as the world skirted that very real possibility more and more closely.
Race issues and other social ills (including the feminist movement) came more to the fore during the 1950s and 1960s, as any comprehensive glance at sf of the time will show; and the establishment versus the counterculture was not only a major theme of the 1960s through the mid- to late-1970s, but even created a new movement in sf, which took varying though related forms (again) between England and the U.S.
The rise of rampant consumerism and of neoconservatism has been a major theme in sf since the 1980s, as well as the various possibilities (good and bad) of cyberspace.
As I mentioned elsewhere, look for a major event or social trend, and you'll find that sf reflects it strongly. While not attempting to be prophets, the vast majority of good sf writers have always been concerned about where we're going and what the human cost may be. All you need to do is get a decent overview of the history of the last 100-150 years, and a good guide of the sf coming out at those different times, and you'll find more connections than you could imagine.
In this case, it's going to be more a wealth of riches than a sparsity of materials; you're going to have to make the decision where to pick-and-choose.
