You are probably wondering how we have any idea what the climate was like 50 million years ago. Obviously, no humans were around to keep records on the weather. So what do we use to obtain information about the equable climates?

There are lots of different methods to get the information, but all of them use natural records, such as plant and animal fossils. The information obtained from natural records is known as "proxy data," which National Environmental Satellite, Data, and Information Service defines as "data that paleoclimatologists gather from natural recorders of climate variability." Scientists use this proxy data in a variety of ways to determine what the climate was like before recorded history. For example, scientists study fossils' chemical compositions and their locations to estimate the temperature while the organisms were alive. The chart below summarizes some of the methods that scientists use. Click on the boxes to learn more about any of the topics.

Evidence Tree

Nearest Living Relative 
			Analysis Isotope Analysis Palm Fossil Alligator Foram