1. Knowledge is increasing. Humans are gaining knowledge at a faster rate than ever before. I would argue that this applies not just to general knowledge about technology, the universe, the human body, etc., but to knowledge about other people. In times past, people in Ontario didn't have much of an idea about what was going on in the daily lives of people in South Carolina. Now with things such as blogs and social media, we can keep up with the most intimate details of the life of a stranger living a continent away.
2. People are traveling more than ever before in history. This is because it is easier to travel now than it ever was, airport security notwithstanding. A hundred years ago, someone in Canada couldn't go down to Florida over Christmas vacation. It would take you two months just to get down there in your Model T. Wanna go to Italy for a couple weeks holidays? Until a couple generations ago, it would take you six weeks to get there by ship, if you didn't get attacked by pirates or blown off course or wreck on a rock someplace.
3. We can't keep going on like this. At the rate we're using our planet's resources, we'll kill ourselves off in a few decades. It is literally going to take divine intervention to put a stop to humanity destroying itself.
4. World events affect more people than ever before. There have always been earthquakes, famines, etc., but they have tended to impact only those living in the immediate area. The reason for this is that for most of history, economies were localised. Now, with our global economy, if there's flooding in China and the crops get destroyed, it raises the prices of food in supermarkets here in the West.
5. We can reap more destruction faster than before. Ever heard of someone in the old west carrying out a mass shooting with a musket? With the kinds of weapons we have today, we can kill more people in a shorter period of time than at any other time in history.
6. We can sin in more ways than we ever could in the past. The Romans may have had their orgies in the park, but they didn't put cell phone video of them on the internet for all to see.