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.