Having done a lot of traveling along with a lot of reading (often at the same time), just reading about a place is a good start, but there's no substitute for actually going there, meeting real people, eating the food, dealing with public transportation and the weather, experiencing all the tiny inconveniences and innovations that shape life. It broadens your worldview, confirming beyond a doubt that the way things are done in your town is neither the only nor the best way, just one of many, and that the people who live "over there" are in fact people, not just statistics.

I agree that the environmental impact is a big problem. But perhaps if more people traveled, we would be more likely to get the kind of international cooperation we need to tackle climate change systemically.