Uncertainty in the response of sudden stratospheric warmings and stratosphere‐troposphere coupling to quadrupled CO2 concentrations in CMIP6 models by Ayarzagüena, B, Charlton-Perez, AJ, Butler, AH, Hitchcock, P, Simpson, IR, Polvani, LM, Butchart, N, Gerber, EP, Gray, L, Hassler, B, Lin, P, Lott, F, Manzini, E, Mizuta, R, Orbe, C, Osprey, S, Saint-Martin, D, Sigmond, M, Taguchi, M, Volodin, EM, Watanabe, S