Complicated Response of ENSO to Higher CO2 Forcing in a Simple Model

De-Zheng Sun, Fudan University, Atmospheric and Oceanic Sciences, Shanghai, China, Jin Liang, Nanjing University, Nanjing, China, Institute for Climate and Global Change Research, School of Atmospheric Sciences, Nanjing, China and Xiu-Qun Yang, Nanjing University, School of Atmospheric Sciences, Nanjing, China