The list of benefits to taking a vacation does not typically include saving the environment -- or even being nice to it. Even though there are many forms of travel that range in eco-friendliness, the only way to be 100% sure you're not hurting the environment on your trip is to simply not go at all.
Travel can be very polluting when factoring in the different aspects of the trip. From the method of transportation used to how much you pack are all components of the overall carbon footprint you'll leave behind.