Paleoclimate & Climate Change
The Geologic Time Scale
Low Resolution past 600 million
Vostok Data Past ½ million years
Younger Dryas Event = Big Freeze
The Younger Dryas Event 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!
A Dramatic Temp Decline
Younger Dryas Event
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 Atlantic Conveyor
Recent Events
The Maunder Minimum
1650 – 1720 Maunder Minimum
The Future
We are currently in an interglacial period. Past data would suggest that we should be heading into a cooling period however….
The Keeling Curve
Future CO2 Projections
Future Temperature Projections
Sea Level Projections
Gases Contributing to the Greenhouse EffectGas Formula Contribution
Water Vapor H2O 36 – 72%
Carbon Dioxide CO2 9 – 26%
Methane CH4 4 – 9%
Ozone O3 3 -7%
Carbon Dioxide
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
Future Climate Maps for US
Global Climate Precip. Forecast
Final Summary
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.