Earth watch - A 20 year old nonprofit charity which allows volunteers to participate on peer reviewed scientific and conservation projects around the planet. We got their catalog of expeditions. We were a bit surprised by the fact that one has to be volunteer twice. That is, you go and do work in a trip according to your qualification but you also pay what would be the equivalent of a luxury vacation. This must mean that not only do you participate by your work, but you also sponsor the project financially. Is this because by the nature of the projects, it’s impossible to get research grants? It does not seem likely to me since many of these clearly originate from university research groups.
I wish a middle ground were possible, by which you participate as a volunteer without having to sponsor the project. (Apart from plane ticket and personal expenses of course). They fill up on all their Volunteer vacations trips.