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.