The best way to search PUBMED is by converting our keywords into Medical Subject Headings. These are also called Controlled Vocabulary. It means indexers at the National Library of Medicine who create the index PUBMED map all the possible natural language keywords to one preferred term called the Medical Subject Heading - MeSH.
I searched in the MeSH database for our keywords
("Climate Change"[Mesh]) AND "Communicable Diseases, Emerging"[Mesh]
This search gave me
