Here's a Google n-gram of the two terms: https://books.google.com/ngrams/graph?content=climate+change%2Cglobal+warming&year_start=1960&year_end=2008&corpus=15&

Here's a Google n-gram of the two terms: https://books.google.com/ngrams/graph?content=climate+change%2Cglobal+warming&year_start=1960&year_end=2008&corpus=15&smoothing=1&share=&direct_url=t1%3B%2Cclimate%20change%3B%2Cc0%3B.t1%3B%2Cglobal%20warming%3B%2Cc0 https://books.google.com/ngrams/graph?content=climate+change... ...I wonder if there is a similar tool for other types of publications besides books.