The paper by Ludescher _et al_ that caused the stir is now available for free at a certain location:

• Josef Ludescher, Avi Gozolchiani, Mikhail I. Bogachev, Armin Bunde, Shlomo Havlin, and Hans Joachim Schellnhuber, Very early warning of next El Niño, Proceedings of the National Academy of Sciences, February 2014.

I've updated various links to point to this free version.