Though many speculate that energy costs and taxes could rise as a result of carbon cap-and-trade legislation, SNRE and Gerald Ford School of Public Policy professor Barry Rabe tells the St. Petersburg Times that predicting the impact on energy costs is more complex than assumed.  "What we've seen is that there's a lot of volatility," he said. "It's hard to make those projections and say how these things are going to work as a result. That just underscores the difficulty of attaching numbers to these things that people can live with."