2-7: Paleoclimate; Ice Core and Lake Sediment Records

Importance of this Unit to the Course

We have seen in previous units that climate models can give simulations of past as well as present and future climates. But we don't have temperature measurements going back more than about 150 years, so we rely on "proxy" measurements of temperature and precipitation to provide evidence climatic conditions hundreds and thousands of years ago. This will allow us to test climate models for accuracy and also offer a better perspective of current climate conditions and how much they might be expected to change if the future were to be similar to the past.

Objectives

To review the record of past climate changes as revealed through proxy data (e.g., non-meteorological information such as tree rings and ice cores) in order to give perspective to present and future climate changes.
To compare the simulations of past climates by use of global climate models with actual data on climate change.

Preparation for Discussion (You must complete this section before class.)

Read the summary information. (Print text for offline review; images only.)

Take the Quiz

Review additional reading material (this material is not covered in the quiz, but offers more ideas for online discussion)

None

Discussion (online / face-to-face) (See your portfolio for due dates and times)

A major component of the course is participation in the online dialog. The following types of comments are required:

Social Comments
Knowledge-building Comments
Ethical Comments

The following may be used as discussion starters for the online dialog:

Unit Problem to Ponder:

If the paleoclimate record showed that we had major droughts (lasting 20 years) that seemed to reoccur every 300 years and we haven't had one for 400 years, will it be highly likely that we will get one in the next decade?
How is it possible to get tree ring data from 1000 years ago in an area where there are no trees older than 200 years?
Unit exam questions from previous years
Unit discussions from previous years, available from the current online discussion

Additional Reading