This is a sequence of 5 classroom activities focusing on the El NiÃo climate variability. The activities increase in complexity and student-directedness. The focus of the activities is on accessing and manipulating real data to help students understand El NiÃo as an interaction of Earth systems.

This video features University of Wisconsin-Madison researcher John Magnuson, who studies the ecology of freshwater systems. He explains the difference between weather and climate using data on ice cover from Lake Mendota in Madison, WI. Analysis of the data indicates a long-term trend that can be connected to climate change.

This animation depicts global surface warming as simulated by NCAR's Community Climate System Model (CCSM) Version 3. It shows the temperature anomalies relative to the end of the 19th century (1870-1899), both over the entire globe and as a global average. The model shows the temporary cooling effects during the 5 major volcanic eruptions of this time period, and then the model's estimates of warming under the different scenarios taken from the fourth IPCC report.

This video describes the role that dendrochronology plays in understanding climate change, especially changes to high elevation environments at an upper tree line. Dendrochronologists from the Big Sky Institute sample living and dead trees, describe how correlations between trees are made, and explain how tree cores record climate changes.

In this activity, students are introduced to tree rings by examining a cross section of a tree, also known as a 'tree cookie.' They discover how tree age can be determined by studying the rings and how ring thickness can be used to deduce times of optimal growing conditions. Next, they investigate simulated tree rings applying the scientific method to explore how climatic conditions varied over time.

In this video, a PhD Student from the University of Maine explains how ice cores are used to study global climate change.

This video describes the impact of extreme heat on Philadelphia in the summer of 2011 and how the city is adapting to new expectations about its weather. It uses this example to introduce the new national climate normals, released by NOAA's National Climatic Data Center (NCDC) that summer.

In this activity from the Deep Earth Academy, students divide into groups to read and discuss one of nine short articles (1-2 pages) about research done by the Ocean Drilling Program. These articles discuss our understanding about past climate based on collected data. These articles briefly describe the research conducted and the findings. Students use the information from the article to complete a write-up that they share with other students. An extension activity involves examining ocean drilling data using Google Earth.

In this activity, students learn about sea ice extent in both polar regions (Arctic and Antarctic). They start out by forming a hypothesis on the variability of sea ice, testing the hypothesis by graphing real data from a recent 3-year period to learn about seasonal variations and over a 25-year period to learn about longer-term trends, and finish with a discussion of their results and predictions.

This short video describes how the compression of Antarctic snow into ice captures air from past atmospheres. It shows how ice cores are drilled from the Antarctic ice and prepared for shipment and subsequent analysis.