Grim,
I wouldn't worry too much about this - that figure refers to 'proven' reserves, and for about the last 50 years, proven reserves have remained largely constant, ie they have ALWAYS been saying we only have 25yrs of fuel left. I suspect this is a 2-proged attack from OPEC - their appeasement to the whale-kissing lobby, AND an attempt to stabilise prices at their current, higher-than-ever levels. Although largely due to geopolitical circumstances, OPEC have been doing quite nicely thank you out of it, and are simply trying to stop prices sliding back to their histroical norms of $25-30 a barrel.
The difference here is between 'proven' reserves and 'known' reserves, in areas where oil is known to exist but drilling / exploration hasn't yet exploited it. The Alaskan peninnsular is 'known' to contain vast reserves, as are certain off-shore areas of the US, but they haven't yet been declared 'proven' or exploited, largeley as a sop to the afforementioned whale-kissers.
As for alternative power units for aircraft - well, where can we go? The only other viable means of power is nuclear-generated electricity, the equipment for which is far too heavy for aviation applications, as are fuel cells (which require vast amounts of electricity in the first place to hydrolyse water to harvest hydrogen fuel). Any suggestions? I'm sure fellow ppruners can dream up some novel solutions!