I finally managed to watch An Inconvenient Truth a few weeks back, because I has heard so much about how effective a presentation it was, and I wanted to try to figure out what made it so effective.
The number one lesson and reason for its success, in my mind, is this:
Make what you're talking about concrete. Make it real and tangible.
Climate change has got to be one of the most abstract subjects imaginable. It covers thousands of years of data, highly complex computer simulations, and so on.
But Gore find something concrete to make the point: a devastating series of pictures showing snow and ice retreating in mountain range after mountain range. Suddenly, you're sitting thinking, "This is not something to worry about in the next two hundred years, it's been happening in front of my eyes."
And he shows the pictures right next to each other, not right after the other, so the images are within "eyespan," as Edward Tufte puts it, and can be immediately compared.
Whenever possible, show real physical objects, not just graphs. Our brains seem highly responsive to these. Just think of how many of our common expressions make abstract things understandable by referring to physical objects. To attempt to lead is to "step up to the plate." To set high ambitions is to "raise the bar." And so on.
Gore had lots of other advantages, too. Superb rehearsal, which showed in the perfect synchrony of his speech as years are ticking by in a timeline behind him. The biggest screens I've ever seen, allowing him to pull off the great visual point to get up on a cherry picker to indicate the predicted top of a exponential trend. And just excellent, low key, simple graphics. I think some those graphs could have been improved somewhat, but that is quibbling over details. An Inconvenient Truth is a fantastic presentation.