"High evaporation" refers to the process of a liquid turning into a gas or vapor at a faster rate than usual due to certain conditions such as heat or low humidity. Full definition
The increased temperatures cause higher evaporation rates meaning more moisture is pulled out of the tees. (lifeinism.com)
High evaporation rates in a warm autumn can actually lead to more ice cover the following winter and slower ice breakup in the spring, because the water is colder after evaporation. (sciencenews.org)
Coming back to the main point, if you want to continue the dispute over the conclusion that the weather is, as I said at the start of all this, getting hotter and drier [as we have discovered in the discussion, as a result of higher evaporation as well as lower rainfall], I suggest you move the discussion to the thread on «Drying out». (johnquiggin.com)