Physicist John Cook (creator of Skeptikal Science) has done us a great service by posting good one-line responses and then updating them as the science evolves and as people offer better ways of phrasing.
95-99%: that’s the level of certainty that scientists have that humans are causing the world to heat up (350.org)
Global warming is too colossal of an issue to summarize on a whiteboard, but the way this guy divides the possible futures of humanity makes a lot of sense.
From the Goddard Space Flight Center: Scientific Visualization Studio