The bad thing about global warming is that the window of opportunity to avoid it is now shut. It's happening, and all we can do anymore is prepare for it, try to limit or ameliorate its effects (we still have time to do that) and adapt to the new reality.
The good thing is that at least it is easy to explain to those who have questions. The effects are already obviously at a glance, and unlike many scientific theories, global warming is working in a way that requires little explanation and which ordinary people even without a scientific background can understand.
The main areas where the predictions made by models in the seventies, which are now being borne out, have to do with 1) rising sea levels, 2) more and bigger hurricanes, and 3) shifting weather patterns. In the southwest, where I live, the models have predicted a drier climate.
Here is why all those things are occurring.
1. Rising sea levels. This is due to the melting of the polar ice caps (see the picture). In fact, while the pictures are dramatic, the reduction in Arctic sea ice, and the breaking apart of Antarctic ice shelves, are by themselves a relatively small contributor to rising sea levels (mainly because Arctic ice is relatively thin, and it is already on an ocean.) The major contribution comes from the melting of polar icecaps in Greenland and Antarctica. For example, with the breakup of the Larsen B and beginning breakup of the Ross ice shelf which act as barriers to ice sheet collapse, the West Antarctic ice sheet (which contains 11% of that continent's ice) is beginning to collapse (a process that in itself will take centuries, but even the effects on a yearly basis are significant). The EPA estimates that sea levels could rise 2-7 feet in the next century. This could completely submerge a number of island nations like Tonga and the Maldives, literally wiping them off the map (for example, the highest point in the Maldives is 3 feet above sea level) while causing major flooding in coastal areas of continents.
2. More and bigger hurricanes. After the disastrous 2004 Atlantic hurricane season (almost seems like ancient history now, but in 2004, Charlie, Frances Ivan and Jeanne turned Florida into a living hell all summer), global warming apologists were quick to say that we are headed into a natural cycle that corresponds to more hurricanes. Fair enough. But in 2005, we saw three of the seven most powerful Atlantic storms on record (including the most powerful, Wilma, which at its most powerful measured 882 mb of central pressure), set (and in fact shattered) the records for most named storms, most hurricanes, most major hurricanes (cat 3 or larger) and most storms hitting land. This was a freakishly powerful season, and there is nothing 'natural' about it. If we are in a 'naturally' more active hurricane cycle, that could be a part of why we saw so many, but there is obviously something more superimposed on top of that. And, here is why global warming causes more large hurricanes. Surface temperatures of water in the tropics are key. The warmer the water, the more energy a hurricane can draw from it. And, it turns out that water temperatures are now higher than they ever have been (for example, water temperatures in the northern Gulf of Mexico approach 90 degrees on the hottest days of the summer. And you need look no farther than the Guiness book of world records from just about a deacade ago to read about how the Persian Gulf (then at 85 degree surface temperature) had the warmest seawater in the world. So, sea surface temperatures have increased. Ergo, stronger hurricanes.
3. Drought in the southwest and other unusual weather. In fact there is nothing unusual about it. Storms travel in a storm track, following the jet stream. The jet stream forms (in fact is driven by) the boundary between warm tropical air and cold polar air. With relatively more warm air and less cold air (global warming again) that boundary moves north. So do the storms. So the southwestern U.S. (including Arizona, where I live), which used to get our fair share of jet stream borne storms, is now generally out of the loop. Most of our snow is going to Utah and Colorado (while conversely the northwest is getting wetter especially in winter, as the jet now is more likely to dump more snow than usual in Washington and the northern Rockies.
None of this requires a degree in climatology to understand. Just explain it simply, and people get it.