I believe this is a temporary problem-- that degree of warping is just mild and fairly simple geometrical transformation.
When will alphanumeric captchas become useless?
Within 5 years
5 to 10 years
10 to 20 years
5 minutes before the Singularity, so don't worry about it
Other-- please discuss
No opinion but want the poll results handy
If the usual captchas are useless, one solution is to go to simple semantic captchas. I've seen a few of those which require answering a very simple arithmetic problem or figuring that "What is the opposite of hot?" isn't a trick question.
Are there other possibilities? Will the reverse Turing test (machines recognizing people) continue to be reliably solvable?