This.
Those who dismiss man-made climate change on the basis that natural fluctuations in global climate exist often fail to realize that we have no way of knowing for certain when/if the climate will ever turn around. We can either make the assumption that we'll be just fine, or we can continue searching for new alternative energy sources that will help relieve our dependence on a limited supply of fossil fuels and also just make the world a cleaner place for all life.