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 Earth Exploration Toolbook chapter is a detailed computer-based exploration in which students learn how various climatic conditions impact the formations of sediment layers on the ocean floor. They analyze sediment core data from the Ross Ice Shelf in Antarctica for evidence of climate changes over time. In addition, they interact with various tools and animations throughout the activity, in particular the Paleontological Stratigraphic Interval Construction and Analysis Tool (PSICAT) that is used to construct a climate change model of a sediment core from core images.

This video explores the work of environmentalist John Hart, a Professor of Environmental Science at U.C. Berkley. In the Rocky Mountains of Colorado, Dr. Hart has established an experimental laboratory in which he has artificially created and maintained a 3-degree increase in surface temperature of a plot of land, and documented the impact on plant species occupying the plot.

This video follows biologist Gretchen Hofmann as she studies the effects of ocean acidification on sea urchin larvae.

This short video shows an example of melting alpine glaciers in the Austrian Alps (Goldberg Glacier). Disappearing alpine glaciers have social and environmental impacts, including the decline of fresh water supplies and contributions to sea level rise.

This visualization graphically displays temperature and CO2 concentration in the atmosphere as derived from ice core data from 400,000 years ago to 1950. The data originates from UNEP GRID Arendal's graphic library of CO2 levels from Vostok ice core.

This video examines the thawing of permafrost due to changes in climate and shows examples of the impacts that warming temperatures have on permafrost in the Arctic, including the release of the greenhouse gas methane. Dramatic results are shown, including sink holes forming on the landscape and beneath buildings, roads, and other infrastructure, causing some communities to relocate.

This video introduces phytoplankton - the base of the marine food web, the source of half of the oxygen on Earth, and an important remover of CO2 from the atmosphere. The video also explains how satellites are used to monitor phytoplankton and how warming waters and acidification negatively affect phytoplankton.