LDEO NGSS Summer Institutes: “Teaching about Weather and Climate” (GED 7212)

Lesson 8: Reconstructing Past Climates

Expected Time Required: 4 – 5 hrs

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Introduction

Instrumental records of weather conditions that provide climate data go back less than 150 years, so how can we know what climates were centuries, millenia, or millions of years ago? We have found a variety of “proxies” that can give us some understanding of what happened in many parts of the globe, including the oceans. Studying these assists us in recognizing what is happening now and what may happen in the future.
In this Lesson, you will learn about selected proxies and explore strategies to incorporate similar lessons into your teaching.
One useful guide is the Paleoclimatology website developed by the NOAA National Centers for Environmental Information. Explore this and provide notes about what you would want to use from these resources.
Decades-to-Centuries
We’ll begin with dendrochronology, the study of tree rings, which can provide glimpses of climate patterns over the past few decades to several hundred years ago.
Many resources are available to teach your students and you about the techniques used by dendrochronologists and their research discoveries. Examine some of these to get background knowledge:
“A Guide to Dendrochronology for Educators” by Lori Martinez
“Resources for Dendrochronologists” by Henri D. Grissino-Mayer
“Build a Tree-Ring Timeline” by Rick Groleau
Examine these and make notes of how you might use them,
LDEO Tree Ring Lab scientists have provided several Earth2Class Workshops which provided excellent resources for your students and you. The most recent was presented in April 2017: “More than How Old? Understanding Climate Changes from Tree Rings” with Mukund Palat Rao, Daniel Bishop, and Rose Oelkers.
Explore what is available here and explain some strategies to develop lessons based om these resources.
What might be available on your school campus or community to teach students about past climates using tree rings?
Climate-Sensitive Isotopes Going Back Thousands to Millions of Years

Most people know we can use isotopes such as C-14 to obtain an approximate age of ancient materials. Less well known is that we can use certain isotopes as proxies to reconstruct past climate patterns, often going back tens or hundreds or thousands of years, or even longer. In this section, you will learn about some of these.

Perhaps foremost is O-18, a less common isotope than O-16. Begin your study reading about how “The Oxygen Balance” can be used as in paleoclimatology. Provide notes about how you might use this in your lessons.
Next, carry out “The Secrets in the Sediments” activity to see one example of how data from scientific deep-sea drilling has been used to reconstruct climates.
Discuss how you would use this type of activity in your lessons.
Another isotope that has been useful in paleoclimatology is Be-10, which can provide information about when glaciers retreated and rocks were exposed. Dr. Mike Kaplan and others at LDEO have conducted such “cosmogenic” research across the globe.
Look through the resources provided in “How Have Glaciers Behaves in Patagonia in the Past?”. Be sure to view the link to the AMNH Science Bulletin: Shrinking Glaciers: A Chronology of Climate Change.
Explain what you might want to use from these to develop your lessons.
Fossils and Microfossils Reveal Climates Hundreds of Millions of Years Ago

Most people understand that we can use fossils to determine ancient climates hundreds of millions of years ago. For example, coal-forming plant fossils now found in locations like Appalachia in the US and Spitsbergen in the Norwegian Arctic provide evidence of much warmer climates at lower latitudes than exist now. Paleontologists have used amphibian, reptile, and other macrofossils to reconstruct past environments.

In the early 1960s, David Ericson and others at LDEO published the first evidence of the onset of the Pleistocene glaciation based on oceanic foraminifera. Read the abstract of this ground-breaking article to get some background information.

Since then, use of foraminifera, radiolaria, diatoms, and coccolithophoridae has become widely used to identify paleoclimates on land and from deep-sea cores.
View this slideshow about “Going to the Sea Floor and Below” to learn more about deep-sea scientific ocean drilling. Tell how you could use this or similar resources in your teaching.

Educators sailing with JOIDES Resolution scientists have created a suite of climate change activities.
Examine some of these and describe strategies to use them in your teaching.
Of special interest here are “Microfossils: The Ocean’s Storytellers.” Browse through these.

Then download and print a copy of the poster and activities. The left side of the activities provides more information about the microorganisms shown in the poster. The middle and right sides are activities created by JR educators and scientists, including “Secrets of the Sediments” (above.)
Using the poster, complete this “Small Creatures, Big Science” activity. Include your answers with your responses, and describe how you might use this or a similar activity in your teaching.

The LDEO Core Repository

The foresight of the LDEO founder, “Doc” Ewing, to order that all Columbia ships stop wherever they were at noon and collect a piston core sample is the basis for the world-class collection of microfossils and other materials which have revealed great insights about past climates and many other aspects of the Earth System.

Browse through the Core Repository web site to become familiar with what is available.

If you visit the Lamont campus, make arrangements for a visit to the Core Repository—schools visits can often be accommodated. Here is an example of questions to help students learn about the LDEO Core Repository.

Palynology

On final line of evidence about past climates comes from “Palynology,” the study of pollen grains.
Start by going through the information and activities about palynology from this website. Describe how you might use it or a similar set of resources.

Dr. Dorothy Peteet is Lamont’s leading palynologist. Browse through some of the resources in her website to see results of some of her research.
View her 2009 LDEO Public Lecture about the Piermont Marsh, located at the base of the Palisades below the Lamont campus.

Describe how you might use it or a similar set of resources.

Additional Thoughts on How You Could Teach about Past Climates

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