I have to say the the increase in alcoholic content is a result of refined agronomics and science along with a "trend" and "taste" of the growers, drinkers and the market. We can put a man on the moon but want to blame global warming for adding 1% more alcohol to an alcoholic beverage? Questions or comments?
It's common practice for winemakers to push the limits, and sometimes for common sense, at least at the high-end. The top boutique wines are so fruit intense they need a higher alcoholic content for the wine to have balance and be drinkable.
The alcoholic levels are being broken all the time. You see, after the alcoholic content exceeds a specificity, it is no longer 'wine.' And there the tax-mongers step in.
There is a cruel irony at work. The growers and winemakers are making product govt can't keep up with, which should not surprise anyone.