Google Ngram Viewer vs. Climate Change(books.google.com)

https://books.google.com/ngrams/graph?content=climate+change%2Cglobal+warming%2Cco2%2Cdesertification%2Cfossil+fuels%2Crenewable+energy&case_insensitive=on&year_start=1920&year_end=2008&corpus=15&smoothing=1&share=&direct_url=t4%3B%2Cclimate%20change%3B%2Cc0%3B%2Cs0%3B%3Bclimate%20change%3B%2Cc0%3B%3BClimate%20Change%3B%2Cc0%3B%3BClimate%20change%3B%2Cc0%3B%3BCLIMATE%20CHANGE%3B%2Cc0%3B.t4%3B%2Cglobal%20warming%3B%2Cc0%3B%2Cs0%3B%3Bglobal%20warming%3B%2Cc0%3B%3BGlobal%20Warming%3B%2Cc0%3B%3BGlobal%20warming%3B%2Cc0%3B%3BGLOBAL%20WARMING%3B%2Cc0%3B.t4%3B%2Cco2%3B%2Cc0%3B%2Cs0%3B%3BCO2%3B%2Cc0%3B%3Bco2%3B%2Cc0%3B%3BCo2%3B%2Cc0%3B.t4%3B%2Cdesertification%3B%2Cc0%3B%2Cs0%3B%3Bdesertification%3B%2Cc0%3B%3BDesertification%3B%2Cc0%3B%3BDESERTIFICATION%3B%2Cc0%3B.t4%3B%2Cfossil%20fuels%3B%2Cc0%3B%2Cs0%3B%3Bfossil%20fuels%3B%2Cc0%3B%3BFossil%20fuels%3B%2Cc0%3B%3BFossil%20Fuels%3B%2Cc0%3B%3BFOSSIL%20FUELS%3B%2Cc0%3B.t4%3B%2Crenewable%20energy%3B%2Cc0%3B%2Cs0%3B%3Brenewable%20energy%3B%2Cc0%3B%3BRenewable%20Energy%3B%2Cc0%3B%3BRenewable%20energy%3B%2Cc0%3B%3BRENEWABLE%20ENERGY%3B%2Cc0