the warming climate will make conditions "increasingly ideal" for disease-carrying insects to establish themselves ...... I was wondering whether you can have even more ideal than ideal

There could be, perhaps, the ideal temperature but the less than ideal humidity. A warming climate could be bringing more factors into alignment.

Or, possibly, the ideal conditions, which have previously only existed for a short period each year, could be occurring earlier and lasting longer.

Just my thoughts as a point for discussion.

DC