Add to ORKGHow do scientists gather data to determine whether global temperatures are warming? Past climatic conditions are recorded in tree rings, skeletons of tropical coral reefs, ice cores from glaciers and ice caps, and laminated sediments from lakes and oceans. Site provides an in-depth look at topics significant to climate change. Resources include slide sets, external links, a Climate TimeLine Information Tool, and a page in Spanish. Educational levels: Middle school, High school