The Mayans show that climate change does matter

http://www.rawstory.com/rs/2014/12/archeologists-find-more-evidence-that-drought-brought-down-the-mayan-empire/

"During the era when the Mayan empire declined, Droxler said, the region underwent significantly fewer major tropical typhoons — only one or two every 20 years instead of the usual five or six. While typhoons can bring devastating winds and flooding, they also bring much-needed water inland in the form of heavy rains.
These heavy rains were an integral part of growing enough food to sustain the sprawling empire. The first great blow to the civilization came in the form of a 100-year drought between 800 A.D. and 900. When the rains stopped, food because scarce and a period of violent unrest ensued."

Climate change can bring an end to civilizations.  If it's changing, for whatever reason, we need to know how so we can plan ahead.