These are natural fluctuations. NOT man made climate change. Remember the Ice Age that parked massive glaciers here in the Midwest then natural warming trends melted them over hundreds of years and created the 5 great Lakes 10-12,000 years ago? Same thing happened in Russia that was the melted glacier now Lake Baikal, biggest fresh water lake on Earth. So do not be fooled with climate change talk induced by human impacts, this planet operates with forces far beyond those type impacts. Think volcanoes, hurricanes etc