Picture a straight trend line going from the bottom left of a graph to the upper right. That's a pretty clear trend. But the climate system has a lot of internal variability which makes that trend line actually look like a very squiggly line, so much so that the initial straight trend line isn't really apparent anymore. The data has become quite noisy. That internal variability includes processes intrinsic to the atmosphere, ocean, land, and cryosphere and their interactions, and it takes a lot of effort to be able to pick out certain trends caused by specific phenomena; however, as certain signals become stronger they become more clear, more evident and apparent, the data becomes less noisy with respect to the stronger signal, that straight line trend begins to emerge again. So right now the signal isn't obvious, but it will be by ~2030.