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Climate, Cryosphere



Global warming got you worried? Wish you had a machine that could transport you back to a place in time when the Earth's climate was not so "iffy"? Much of what you already know about climate change and even more of what paleoclimatologists know about Earth's climate history and predicting future climate was learned from the study of ice cores.

Ice cores are frozen time machines. They can take scientists back a few or hundreds of thousands of years into Earth's past. Scientists use what they find trapped in the ice core layers to explore changes in the Earth's climate and other environmental indicators. They use these records from the past to generate models for predicting the impact of current events on climate change in the future.

Ice cores can be a few meters or thousands of meters long. They can come from high mountain glaciers or from ice sheets in Greenland or Antarctica, places with heavy snow fall and very little or no melting during the summer seasons. Over periods of time the snow is compacted into firn. Over even longer periods of time, the firn gets denser under the increasing pressure of the additional layers of snow, eventually forming ice and trapping the particles and gases that were in the spaces between the snowflakes. Year after year, new blankets of snow build up over the old layers creating a frozen timeline of Earth's past.

What's trapped in ice cores? Interesting stuff, some of it from anthropogenic (human-related) sources and a bunch of it from natural sources. There are water molecules, particles of dust and bubbles of gas. The dust particles contain nitrates, sulfates and sodium salts that were blown from stormy oceans, spewed into the air by volcanic eruptions or carried by the winds from arid land. There are radioactive particles, too. The gas bubbles are filled with carbon dioxide, nitrous oxide, methane and other greenhouse gases. And the frozen water molecules themselves contain isotopes of hydrogen and oxygen that help date the ice layers and to calculate the local temperature when the snow fell.

The concentrations and composition of the materials in ice cores help scientists track changes in factors that affect climate called climate forcing mechanisms or "forcings". A positive forcing results in a period of warming while a negative forcing produces a period of cooling. Some of the most important forcings are: changes in the output of energy from the Sun, volcanic eruptions, and changes in concentrations of greenhouse gases in the atmosphere. Straightforward corrlelations between climate forcing mechanisms and climate conditions or change are difficult to establish because of responses and feedbacks in the Earth's system like thermohaline circulation.

Ice cores contain climate proxy data or data sets, like tree rings and sediment layers. The thickness of tree rings can be used to determine rainfall and temperature trends. Scientists use the shells of tiny animals found in ocean sediment layers to reconstruct Earth's climate history. Variations in shell compositions and the abundance of different species of tiny animals like foraminifera (forams) found in ocean sediment layers allow scientists to determine changes in the atmosphere, ocean surface and deep temperatures, ice volume, and other factors affecting climate. Climate proxies give scientists tools to determine not only the effects, but causes of climate change. The relationships between atmospheric changes, ocean temperatures, ice volume and Earth's orbit have led to the development of an astronomical theory of climate change to explain Earth's glacial cycles.

In ice cores, the upper most layers of an ice core are relatively easy to date. Seasonal layers may even be visible. Layers of volcanic ash and other particulates can help date areas of some cores. Dating the ice layers and the trapped materials is tricky, but scientists have developed a variety of methods that have improved confidence in their results. Correlating the dates, concentration levels and types of gases and materials found to local temperatures at the time the layer was formed, is even trickier and continues to be revised and tuned. Some findings are controversial and conclusions about what all of the data tells us about future climate trends are still debated.

Ice cores are frozen time machines. They are windows to the past and tools for predicting the future. What we have learned from ice cores helps us understand how natural and anthropogenic factors affect Earth's climate. Revealing the history of the past opens a window to the future. The stories are there, frozen in the ice.

"Are we on the brink of a New Little Ice Age?" This article written by senior scientists at the Woods Hole Oceanographic Institute, explores current thinking about global climate change. According to the article, focusing on slow changes to the climate and how these changes impact humans and the habitability of our planet fails to take into account the well-established fact that climate has changed abruptly many times in the past.

Because of your interest in using climate proxy data sets to reconstruct past climate conditions, National Science Foundation scientists have asked your team of interns to examine in depth one example of abrupt climate change, the Younger Dryas event. The Younger Dryas period of cooling happened about 12,000 YBP at a time when orbital forcing should have continued to drive climate to its present warm state. The Younger Dryas is clearly evident in Greenland and Antarctic ice cores.

The NSF wants you use ice core data to contribute to what we know about the Younger Dryas. To assist you in developing your understanding of ice core analysis, they ask you to complete an investigation of the Vostok ice core. To help confirm your thinking, they ask you to examine results from foraminifera (foram) analyses presented here, as well. Use the trends you see in the Vostok data sets, the results from the foram analyses and other resources to develop an ESS model showing activity in the four spheres for the Younger Dryas event. The NSF is interested in your ideas about what caused the Younger Dryas, its impact and what this event might tell us about current and future climate change.

Before you begin the Vostok ice core investigation, please read the Lab Tips.


Date: 2/19/2009

Scenario Images:

Ice Coverage 18000 YBP vs. Modern Day
Ice Coverage Northern Hemisphere: 18000 YBP vs. Modern Day. larger image
Image Credit: Courtesy of NOAA

Southern Hemisphere Ice  Coverage
Ice Coverage Southern Hemisphere: 18000 YBP vs. Modern Day. larger image
Image Credit: Courtesy of NOAA

Extruding Ice Core
Extruding an Ice Core. larger image and more information
Photo Credits: Courtesy of NOAA
Mark Twickler
University of New Hampshire
Courtesy of NOAA

Logging Ice Core
Logging a Core at the NICL. larger image and more information
Photo Credits: Courtesy of NOAA
Ken Abbott
Office of Public Relations, University of Colorado, Boulder.

Ice Core Storage
Ice Core Storage at the National Ice Core Laboratory. larger image and more information
Photo Credits: Courtesy of NOAA
Kendrick Taylor
DRI, University of Nevada-Reno.



1. Ice Core Proxy Methods for Tracking Climate Change (Cycle A)
Ice core and analytical techniques information. CSA Discovery Guide


2. Stories in the Ice (Cycle A)
This NOVA site has an interactive timeline that provides information and graphical representations of ice core data.


3. Paleoclimatology: Ice Core Slide Set (Cycle A)
Great set of images with information about ice cores and the information learned from them.


4. Ice Core Data Sources (Cycle A)
Vostok and other ice core data:

  • CDIAC Climate Holdings Containing Climate Reconstruction Data Access the Vostok historic record graph to compare your isotopic temperature results to that of J.R. Petit et al.
  • The NOAA Paleoclimatology Program, National Snow and Ice Data Center (NSIDC), and the World Data Centers for Paleoclimatology and for Glaciology (Snow and Ice) jointly maintain archives of ice core data from throughout the world. Data from polar and low latitude mountain glaciers and ice caps are archived. Proxy climate indicators include oxygen isotopes, methane concentrations, dust content, and other parameters.


5. Global Climate Change: A Glance in the Rear View Mirror (Cycle A)
This Geotimes article provides an overview of the use of climate proxies.


6. Climate Proxies Advanced Collection (Cycle A)
Links to a variety of proxy related sites and sources.


7. Abrupt Climate Change (Cycle A)
From Lamont-Doherty Earth Observatory the Earth Institute at Columbia University. This resource explores abrupt climate change through a series of questions and answers. The Younger Dryas is discussed in depth as an example of scientific evidence of abrupt climate change.


8. Younger Dryas Event (Cycle A)
What is it? Where was it? And who inhabited the regions where it occurred? From the Hooper Virtual Natural History Museum The Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada . From the Museum Map page, select Climate Change and Rapid Climate Change: A Lesson form the Younger Dryas Cold Episode.


Readings (Cycle A)
Use these and others you find, to increase your understanding of ice core analysis and their connections to Earth's climate.

  • Sources of Uncertainty in Ice Core Data A contribution to the Workshop on
    Reducing and Representing Uncertainties in High-Resolution Proxy Data International Centre for Theoretical Physics, Trieste, Italy, June 9 - 11, 2008
  • Orbital and Millennial Antarctic Climate Variability over the Past 800,000 Years "A high-resolution deuterium profile is now available along the entire European Project for Ice Coring in Antarctica Dome C ice core, extending this climate record back to marine isotope stage 20.2, 800,000 years ago." This Science Magazine article is available free to non-subscribing registered users.


1. Malinkovitch Theory (Cycle B)
Astronomical Theory of Climate Change from NOAA.


2. Antarctic Ice Collapse Began End of Ice Age? (Cycle B)
"The melting of an enormous Antarctic ice sheet 14,000 years ago triggered climatic changes in Europe and North America that ultimately led to the end of the last ice age, according to a new study."


3. Paleovegetation and More by Continent Last Glacial Maximum to Mid-Halocene (Cycle B)
Use the links at this site to access information about more than just vegetation changes since the Last Glacial Maximum. Information about sea levels, temperatures and other climate indicators are included. Select the continent of interest and scroll down to the text. Time frames for the information include 18,000 YBP, 8,000 YBP (early Halocene) and 5,000 YBP (mid-Halocene).


4. The Climate TimeLine Information Tool (Cycle B)
The Climate TimeLine Information Tool is designed as an interactive matrix to allow users to examine climatic information at varying scales through time. Beginning with the daily cycle of Earth's rotation on its axis, the Climate Timeline moves logarithmically using the powers of ten from the daily cycle on its axis(10-.027 years)and annual cycle around the sun(100 years)to 100,000 (105)year timescales and beyond.


5. Abrupt Climate Change: Inevitable Surprises (Cycle B)
This online book resource from the National Academies Press covers a wide variety of abrupt climate change topics. You can access the chapters from the Table of Contents (scroll down the page) or you can use the Search This Book tool to access information about ice cores, Younger Dryas, foraminifera data, and other specific climate change topics of interest.


Readings (Cycle B)
These Science Magazine abstracts use ice core and foraminifera data to investigate changes in paleoclimate.

The full articles are available online free to registered non-subscribers.


1. Greenland Ice Core Analysis Shows Drastic Climate Change Near End Of Last Ice Age (Cycle C)
"The ice core showed the Northern Hemisphere briefly emerged from the last ice age some 14,700 years ago with a 22-degree-Fahrenheit spike in just 50 years, then plunged back into icy conditions before abruptly warming again about 11,700 years ago. Startlingly, the Greenland ice core evidence showed that a massive "reorganization" of atmospheric circulation in the Northern Hemisphere coincided with each temperature spurt, with each reorganization taking just one or two years, said the study authors."


2. Ideas for Teaching with Ice Core Data (Cycle C)
These ideas are not fully-formed teaching activities, but rather they are outlines that could be developed into fully formed activities.


3. NCSE-NASA Curriculum Module - Ice Core Data (Cycle C)
This comprehensive module includes data sets and instructions for completing a series of eight exercises exploring ice core data. Data sets from Greenland and Antarctic core sites are provided. Changes in global sea level, temperature, carbon dioxide and solar insolation are explored.


4. Climate Change Classroom Activities (Cycle C)
Links to 157 activities. A variety of climate change topics are explored.


5. Vital Climate Change Graphics (Cycle C)
Access all types of climate change graphics and information from this online report.


6. Global Climate Change Student Guide (Cycle C)
This guide provides information concerning paleoclomatology, the use of climate proxies and much more.


7. Climate Literacy: "The Essential Principles of Climate Sciences" (Cycle C)
US Climate Change Science Program 2009 edition. Presents information that is deemed important for individuals and communities to know and understand about Earth climate, impacts of climate change, and approaches to adaptation or mitigation.


8. Rescuing the Climate Record with Ice Cores (Cycle C)
A video, Archived in Ice: Rescuing the Climate Record, is presented courtesy of the American Museum of Natural History. It could be used to introduce a class to the concept and importance of storing ice cores.


Readings (Cycle C)
Use these resources and others you find to deepen your understanding of Earth's climate, past and future.

  • New Observations Could Help Predict Climate Change The article discusses the correlative relationship, or "bi-polar see saw," between climate change in Antarctica and Greenland.
  • Antarctic Ice Core Hints Abrupt Warming Some 12,500 Years Ago May Have Been Global "James White, a paleoclimatologist at the University of Colorado at Boulder, said changes in stable isotope ratios -- an indicator of past temperatures in the Taylor Dome ice core from Antarctica -- are almost identical to changes seen in cores from Greenland's GISP 2 core from the same period."
  • Climate Changes Are Linked Between Greenland And The Antarctic "Even shorter and weaker temperature changes in the south are connected to fast changes in temperature in the north by change of ocean currents in the Atlantic ocean. Antarctica always warmed in the time period 10,000 to 55,000 years BP whilst the North remained cold. Concurrently, warm water export from the Southern Ocean to the North Atlantic was reduced. In contrast, the Antarctic started to cool every time more warm water started to flow into the North Atlantic during warm events in the north."
  • Ice, Mud and Blood: Lessons from Climates Past In Ice, Mud and Blood, author Chris Turney explores the changing climate and the risks facing us today as we continue to drive our planet to new extremes.


Sample Investigations:


Lab: Vostok Ice Core (Cycle A)
In this investigation learn how scientists reconstruct Earth's climate history from the particulates, isotopes and atmospheric gases trapped in the Vostok ice cores and other ice cores.
Before beginning this investigation, read the Lab Tips.
Difficulty: advanced


Using Foraminifera Contained in Deep Sea Sediments in Climate Reconstruction (Cycle A)
Use pasta and a cardboard tube to construct deep sea sediment core. Correlate the abundance of forams at different levels in your core to generate temperature profiles. Materials include foraminifera information, videos about analysis and students handouts. Great site from the scientists at Woods Hole.
Difficulty: intermediate


Using Published Ice Core Graphs to Explore Climate Change (Cycle A)
Use this investigation to explore graphs of ice core data and learn more about what the gases and materials in ice cores tell us about past and future climate changes. This investigation could be used in place of the Vostok Lab (does not require Excel) or as a source of published graphs for comparison to those generated in the Vostok Lab Investigation.
From the home page, use the Investigation navigation button to access the entire list of investigations. Scroll down the listing to Chapter 21: Climate and Climate Change and select the "How Do Ice Core Glaciers Tell Us About Climate Past?" investigation.
Difficulty: intermediate


The Climate TimeLine Information Tool (Cycle B)
The Climate TimeLine Information Tool is designed as an interactive matrix to allow users to examine climatic information at varying scales through time. Beginning with the daily cycle of Earth's rotation on its axis, the Climate Timeline moves logarithmically using the powers of ten from the daily cycle on its axis(10-.027 years)and annual cycle around the sun(100 years)to 100,000 (105)year timescales and beyond.
Difficulty: intermediate


Foram Data Subantarctic Zone 2000-543,000 YBP (Cycle C)
Use this dataset and Excel to create your own foraminfera profiles. Dataset is available in tab-delimited text for import into Excel. You decide which species and parameters to investigate.
Difficulty: advanced


Using Real Data from Ices Cores and Salt Cores to Interpret Paleoclimate (Cycle C)
In this investigation you will compare data from two ice cores (Vostok and GRIP) and two halite cores (Death Valley and Chile) to identify core trends, explore core correlations and distinguish local, regional and global warming and cooling trends.
Difficulty: advanced




  • Science
    National Science Education Standards - Science Content Standards The science content standards outline what students should know, understand, and be able to do in the natural sciences over the course of K-12 education.
      • Science as Inquiry (Std A)
        • Abilities necessary to do scientific inquiry
        • Understanding about scientific inquiry
      • Physical Science (Std B)
        • Structure of atoms
        • Structure and properties of matter
      • Life Science (Std C)
        • Behavior of organisms
      • Earth and Space Science (Std D)
        • Energy in the earth system
        • Geochemical cycles
        • Origin and evolution of the earth system
      • Science and Technology (Std E)
        • Understanding about science and technology
      • Science in Personal and Social Perspectives (Std F)
        • Environmental quality
        • Natural and human-induced hazards
        • Science and technology in local, national, and global challenges
      • History and Nature of Science (Std G)
        • Science as a human endeavor
        • Nature of scientific knowledge
  • Mathematics
    Principles and Standards for School Mathematics, National Council of Teachers of Mathematics (NCTM), 2000 This set of Standards proposes the mathematics concepts that all students should have the opportunity to learn. Each of these ten Standards applies across all grades, prekindergarten through grade 12. Even though each of these ten Standards applies to all grades, emphases and expectations will vary both within and between the grade bands (K-2, 3-5, 6-8, 9-12). For instance, the emphasis on number is greatest in prekindergarten through grade 2, and by grades 9-12, number receives less instructional attention. Also the total time for mathematical instruction will be divided differently according to particular needs in each grade band - for example, in the middle grades, the majority of instructional time would address algebra and geometry.
      Mathematics instructional programs should foster the development of number and operation sense so that all students—
      • understand numbers, ways of representing numbers, relationships among numbers, and number systems;
      • understand the meaning of operations and how they relate to each other;
      • use computational tools and strategies fluently and estimate appropriately.
      Mathematics instructional programs should include attention to patterns, functions, symbols, and models so that all students—
      • understand various types of patterns and functional relationships;
      • use symbolic forms to represent and analyze mathematical situations and structures;
      • use mathematical models and analyze change in both real and abstract contexts.
      Mathematics instructional programs should include attention to geometry and spatial sense so that all students—
      • use visualization and spatial reasoning to solve problems both within and outside of mathematics.
      Mathematics instructional programs should include attention to measurement so that all students—
      • understand attributes, units, and systems of measurement;
      • apply a variety of techniques, tools, and formulas for determining measurements.
      Mathematics instructional programs should include attention to data analysis, statistics, and probability so that all students—
      • pose questions and collect, organize, and represent data to answer those questions;
      • interpret data using methods of exploratory data analysis;
      • develop and evaluate inferences, predictions, and arguments that are based on data;
      Mathematics instructional programs should focus on solving problems as part of understanding mathematics so that all students—
      • build new mathematical knowledge through their work with problems;
      • develop a disposition to formulate, represent, abstract, and generalize in situations within and outside mathematics;
      • apply a wide variety of strategies to solve problems and adapt the strategies to new situations;
      • monitor and reflect on their mathematical thinking in solving problems.
      Mathematics instructional programs should use communication to foster understanding of mathematics so that all students—
      • organize and consolidate their mathematical thinking to communicate with others;
      • express mathematical ideas coherently and clearly to peers, teachers, and others;
      • extend their mathematical knowledge by considering the thinking and strategies of others;
      • use the language of mathematics as a precise means of mathematical expression.
      Mathematics instructional programs should emphasize connections to foster understanding of mathematics so that all students—
      • recognize, use, and learn about mathematics in contexts outside of mathematics.
      Mathematics instructional programs should emphasize mathematical representations to foster understanding of mathematics so that all students—
      • create and use representations to organize, record, and communicate mathematical ideas;
      • use representations to model and interpret physical, social, and mathematical phenomena.
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