Without major reductions in these emissions, the increase in annual average global temperatures relative to preindustrial times could reach 9°F (5°C) or more by the end of this century (high confidence)."
I'm not particularly disputing this assertion. However, it's sort of like the prediction, "If current trends continue, medical expenses will be 50% of US GDP by some distant date in the future. In both cases the consequences are so costly that some kind of action is likely to occur before that point is reached.
A recent Society of Actuaries magazine commented upon the issue of attributing specific weather events to climate change. The main point is that if 100 year events are occurring every 5 years for example, there's a good case to allocate some fraction of causation of such an event to climate change. The current fire situation is California is perhaps an example. Fires are a natural fact of life in Southern California with normal summer/autumn weather, especially autumn when Santa Ana wind frequency increases. I've lived here most of my life and distinctively remember huge fire seasons in 1961, 1978 and 1993, so nothing new here. But I do not remember such frequency in Northern California, and neither does Liz, who lived there 1964-1971. The Ferguson fire which has closed Yosemite Valley for about two weeks is the third major fire in the foothill region west of Yosemite since the 2012-2015 drought started. The Mendocino Complex fire, now a state record 288,000 acres, is just north of the area that burned in Napa/Santa Rosa last October, and there have been other major fires in that general area since 2012.
The Hurricane Harvey discussion in science2017.globalchange.gov/chapter/1/ is more controversial. It claims Harvey had 15% more water due to higher temperatures. The Gulf of Mexico was in fact only 0.5 degrees warmer than long term average at that time, which is a very modest deviation IMHO. We had our first beach day yesterday, and due to the hot July the ocean here in SoCal is probably 4-5 degrees higher than average. Water at Scripps Pier in San Diego reached a record high of 78.8F during the July heat while we were out of town the entire month.