GENERAL GEOLOGY

Detailed explanation-1: -Ice cores provide direct information about how greenhouse gas concentrations have changed in the past, and they also provide direct evidence that the climate can change abruptly under some circumstances.

Detailed explanation-2: -Scientists study Earth’s climate and how it changes in a variety of different ways, using satellite, instrumental, historical, and environmental records. One challenge of using satellite and instrumental data is that their lifespans have been rather short when compared to Earth’s life.

Detailed explanation-3: -When scientists focus on climate from before the past 100-150 years, they use records from physical, chemical, and biological materials preserved within the geologic record. Organisms (such as diatoms, forams, and coral) can serve as useful climate proxies.