According to this graph from Google Ngram, Climate change is still increasing. Ngram measures how often words are used in our language by counting occurrences in a huge swath of publications that have been digitised. This is a form of corpus linguistics, a field of study that goes back to Vedic scholars counting the occurrences of different sounds in Sansrkit holy texts. Arabic scholars also studied the Koran, and back in 1230 Hugo de Saint Cher made a concordance of the Bible, noting where and how often each word appeared in the holy book. Computers have made this a lot easier, and Corpus Linguistics has really taken off since the 1960s.
Ngram opens that door to anyone interested in what people have been writing, and we can see here that climate change, global warming and greenhouse effect all steadily increased until the mid 1980s, where they received a bit of boost. Global warming used to be more commonly used than climate change, but slowed and then plateaued in the early 1990s, slighly increasing since. At about the same time use of the phrase "greenhouse effect" peaked.
A climate denier may be tempted to interpret this as the greenhouse effect peaking in 1992 and decreasing since, and evidence that the data for climate change and global warming have been tampered with by NASA.
My interpretation is that discussion of this topic became increasingly important from the 1970s, initially led by discussion of the greenhouse effect. This is the method by which global warming was
happening, and reliable historical temperature data began to become available from this time.
By the end of the 1980s the discussion of how global warming happened was more or less decided, and we didn't need to talk about the greenhouse effect so much. I suspect discussion of "round earth" peaked shortly into the age of discovery when returning ships removed any serious doubt about the shape of the planet.
Global warming and climate change were discussed equally, and largely synonymously until 1992. It's not clear why this happened, but in 2002 a Republican party memo by Frank Lunz recommended that the term "climate change" was used rather than "global warming", which people found frightening. It seems that George W Bush did respond to the calls to "stop global warming" by not using the phrase any more. This is not exactly what people wanted! (See also Guardian, 4th March 2003).
A more detailed linguistic investigation by Dr. Martin Döring of the
Institute for Geography at the University of Hamburg into perceptions of regional climate change in North Frisia found: "six prevailing conceptual metaphors: Climate change is an enemy, preventing climate change is fight/war, climate change is punishment for human sins, climate change is overheating/heat, climate change is hot air/hoax and climate change is eco-dictatorship."
Those of us who want to "fight" climate change need to take account of
the last idea: climate change as eco-dictatorship. For some people this may be
overwhelming, for examples libertarians who make up the right wing of
the US Republican Party, for whom denial of climate change is perhaps primarily a rejection of government intervention.
