Trees and Paleoclimate

Introduction

Each year as flowering plants distribute their pollen on the wind, they are also sending out a signal of their location, abundance, and species type. These pollen grains are often deposited in lakes and other shallow and still bodies of water, where, like the snow on a glacier, they settle in annual layers. Over time this pollen becomes fossilized and forms a proxy record of ancient climate.

In this Lab, you'll view an interactive timeline of climate history. You will learn how scientists "know what they know" about past climates and how that data informs models of future climate. To accomplish this, you will view several graphs of climate records for the past 1000 years and consider the evidence of change shown in these records. You will view animations of tree species locations for the past 20,000 years, and you will conduct a model lab using pollen to determine the climate history of Battle Ground Lake, Washington.

After completing this Lab, you should be able to:

• explain what "proxy data" is and give examples of how proxy data provides information about climate of the past.

Keeping Track of What You Learn

In these pages, you'll find three kinds of questions.

• Checking In questions are intended to keep you focused on key concepts. They allow you to check if the material is making sense. These questions are often accompanied by hints or answers to let you know if you are on the right track.
• Stop and Think questions are intended to help your teacher assess your understanding of the key concepts and skills. These questions require you to pull some concepts together or apply your knowledge in a new situation.
• Discuss questions are intended to get you talking with your neighbor. These questions require you to pull some concepts together or apply your knowledge in a new situation. There is no right answer to these questions; just something to ponder.

Your teacher will let you know which questions you should answer and turn in.