b. Environmental observations are the foundation for understanding the climate system. From the bottom of the ocean to the surface of the Sun, instruments on weather stations, buoys, satellites, and other platforms collect climate data. To learn about past climates, scientists use natural records, such as tree rings, ice cores, and sedimentary layers. Historical observations, such as native knowledge and personal journals, also document past climate change.

This graphic depicts evidence for a human fingerprint on climate change based on multiple sets of independent observations. The graphic is available to study at three levels - basic, intermediate, and advanced understanding, with substantial support for students to investigate the evidence themselves and draw their own conclusions.

This video features research conducted at University of Colorado's Institute of Arctic and Alpine Research, which studies isotopes of hydrogen trapped in ice cores to understand climate changes in the past.

This three-panel figure is an infographic showing how carbon and oxygen isotope ratios, temperature, and carbonate sediments have changed during the Palaeocene-Eocene Thermal Maximum. The figure caption provides sources to scientific articles from which this data was derived. A graphic visualization from the Intergovernmental Panel on Climate Change shows the rapid decrease in carbon isotope ratios that is indicative of a large increase in the atmospheric greenhouse gases CO2 and CH4, which was coincident with approximately 5C of global warming.

For this lesson, the guiding Concept Question is: What is climate change and how does climate relate to greenhouse gas concentrations over time? This activity is the second lesson in a nine-lesson module 'Visualizing and Understanding the Science of Climate Change' produced by the International Year of Chemistry project (2011).

This video provides an excellent summary of the role of the oceans and ocean life and makes the point that despite the important role of life in the oceans, there is still much to be learned about the details of the oceanic biota.

This video is the second of a three-video series in the Sea Change project, which follows the work of Dr. Maureen Raymo, paleogeologist at Columbia University's Lamont-Doherty Earth Observatory, who travels with fellow researchers to Australia in search of evidence of sea level that was once higher than it is today.

This short video from Climate Central explains the technology used to monitor changes in Arctic sea ice. Long-term tracking (since the late 1970's) shows Arctic sea ice has been on a steady decline and this could have significant implications for global temperatures.

In this hands-on activity, students will learn about dendrochronology (the study of tree rings to understand ecological conditions in the recent past) and come up with conclusions as to what possible climatic conditions might affect tree growth in their region. Students determine the average age of the trees in their schoolyard, investigate any years of poor growth, and draw conclusions about the reasons for those years.

In this activity, students research various topics about ocean health, e.g. overfishing, habitat destruction, invasive species, climate change, pollution, and ocean acidification. An optional extension activity has them creating an aquatic biosphere in a bottle experiment in which they can manipulate variables.

A video from the Extreme Ice Survey in which Dr. Tad Pfeffer and photographer Jim Balog discuss the dynamics of the Columbia glacier's retreat in recent years through this time-lapse movie. Key point: glacier size is being reduced not just by glacial melting but due to a shift in glacial dynamics brought on by climate change.