How much has Skype/teleconferencing etc. reduced the need for professional academic travel? For me, not at all. These things have reduced the number of traditional phone calls to a very low number, but there has been no decrease in conference travel or travel to other universities to give talks, just to mention two common reasons for professional travel.
For some committees involving geographically dispersed people, we can do some or all of our committee business by email instead of meeting in person, but when we used to meet in person, it was before or during a conference. We still go to the conference, we just don't do committee meetings there.
Technology has not affected my need to travel a lot, but it has increased the level and style of participation of geographically remote colleagues in some of my research group's activities. At some research group meetings, we have had the face and voice of a colleague (typically an international colleague) transmitted via a laptop sitting on a table. It is great fun to rotate the laptop around so that the colleague's head can be facing the person who is speaking.
I can't imagine anything reducing the need to be at a conference in person or to travel to another university to give a talk and meet people. I can, however, imagine having less money for these things, thus reducing the opportunities for travel, but the benefits of in-person interactions in different professional settings is much greater than what can be accomplished via technological methods for transmitting voices and images.
2 years ago