Just discovered your website, great initiative!
I stopped flying a year ago, for environmental concerns, so now I only take the train. I also rapidly discovered plenty of advantages of traveling by train: changing my relationship to time; discovering countries, cities, landscapes that the train goes through; meeting people on the way; and last but very important in our job, I find it the perfect place to work on papers etc. as I am not disturbed by anything else.
It has also some drawbacks, such as it is more expensive than flying; depending on the countries the connections are not always smooth; it is more tiring; and also it means I will never travel outside Europe anymore unless planning a several-weeks-long trip.
Me and some co-workers actually started a similar initiative, much less focused on environment than yours, but the intention is here. If you want to check it: https://lab-allience.natur.cuni.cz/charter19 (the part concerning the environment is in the end, point number 4).
I am a researcher in plant biology. My focus is the evolution of plant reproduction, in short I am interested to know why there is such diversity in color, shape, size, etc. of flowers and fruits in plants.