The science is clear. The next 5-10 years have been identified as a critical period for action and, without significant reductions in global emissions in the very near future, we will be facing a world that it is (on average) four degrees warmer. Droughts, heatwaves, bushfires and floods will become much worse, and our ability to live well in such a world is highly uncertain. Ideally, this would not be the case, but it seems that everyone who studies this material says it is.
At current rates of heating, it will require infinity years to warm four degrees.