In the transition from the last glacier ice age which ended 16,000 years ago to our present day, there was a short period of intense cold. This event occurred 11,000 years ago and is known as the Younger Dryas event. The event lasted 1000 years and temperatures dropped 7 degrees Celsius!
The Younger Dryas caused the extinction of many large mammals across N. America including Saber Toothed Cats, Mammoths, and Mastodons. One possible explanation is that warming temperatures shut down the Atlantic Conveyor creating a dramatic climate event lowering global temperatures.
The atmospheric lifetime of CO2 is estimated to be between 30 to 95 years. An increase in CO2 causes an increase in temperature resulting in an increase in water vapor. It is this water vapor that contributes to most of the warming. Methane is 72 times stronger than CO2 at absorbing heat however it is present in smaller concentrations and has a shorter life in the atmosphere
Climate change means different “things” for different regions of the world. Higher latitudes will experience greater temperature changes. Computer models forecast drier conditions for much of the western and central United States.