One of the predictions of the global warming hypothesis is that precipitation will become much more variable: more droughts, more flooding, more extremes in precipitation events. I decided to see if this holds true for precipitation in Augusta, GA with data available on the wunderground.com website. It didn't take me long to look up the monthly precip figures for 2012, 2002, and 1992, copy them over to a spreadsheet, and have it crunch the statistics.
Year Avg.Mo. precip. (in.) St.Dev. St.Dev as % of Precip
2012 3.01 3.17 105
2002 3.41 1.52 45
1992 4.45 1.91 43
This scant bit of data, just three points over the last 20 years, seems to validate the hypothesis that, at least here in Augusta, GA, precipitation has become more variable. It seems to have more than doubled (going by the standard deviation).
In all the political arguing about global warming, one side seems to rely on observations and data, and the other on everything else. If you are looking for a way to convince your neighbors about the validity of global warming, I would think a very good way would be to analyze your own local data, just like I did, so that you can quantify what's happening right in front of your face.
If this trend, more variability in precipitation, is going to continue, then it makes water conservation and management ever more important. That's what got me so interested in the hugelkultur method of gardening. The large amount of rotting wood under the mounds soaks up the precipitation and makes it available to the plants, all without any irrigation equipment. It takes quite a long dry spell to dry out this Georgia clay, but once it does dry out, be it June or August, it's a lost cause to try to get anything to grow until the fall weather pattern of cold fronts with their associated precipitation sets in.
While we have just come out of a drought (statewide, we are under 5% for any drought stage), it could recur at any time, and this time I will be prepared for it. I hope to have all of my garden converted to hugelkultur beds by the end of the year, and it looks like a goal that I will be able to make. Fortunately, I don't have much of a terrain problem. I am on kind of a knoll, with my neighbors on both sides a little lower in elevation. All I have to do is make sure that I catch what falls and make sure there are no obvious places where runoff can occur.