The Green Party / Comhaontas Glas held a special screening of "An Inconvenient Truth" on 12th Sept.  The documentary film is quite unusual as it is in effect a science lecture.  Al Gore has developed a detailed and very powerful slideshow to put across the science of climate change.  It gives a good understanding of how climate change happens and its consequences.
I strongly recommend it.  More info from http://www.climatecrisis.net/