In part, it's still the hangover from last summer's storms, but it's also caused by the process of changing over to gasoline that is less polluting in the warm weather, and that procedure is more disruptive this year because distributors are switching from the old chemical called NTBE, which has been found to pollute ground water, to ethanol.
That said, if the process really can be made to work, CO2 would go from being a polluting waste product to a valuable raw material, and it might even become worthwhile building systems to capture it and pipelines to ship it around.