1. PART A: Which statement best expresses the central idea of the text? R1.8.2 A. While scientists know that the Earth has been warming since the 1880s, they don't have reliable weather information from before then. B. By studying isotopes trapped in glaciers, scientists can confirm the different types of pollutants that are contributing to global warming. C. Scientists have confirmed the Earth's rapid warming by monitoring weather globally for over a century and studying clues trapped in glaciers from even farther back. D. Even though the Earth is warming, confirmed by both satellite data and ice cores, it's happening at a slow enough rate that scientists are not yet concerned.