Having enough and accurate information about climate in the past, and the constant changes it has been undergoing, is a real challenge for scientists, as it cannot be done directly, for obvious reasons. Researchers need to extend their information much further back than the period about which they can find reliable recorded information (no more than 200 years) and they do so through materials such as old newspapers, paintings, private letters, and almanacs. But for older periods, they have to rely on what is called proxy data. Proxy data are records of phenomena that can be used to make an estimated reconstruction of past climate conditions.
Recording Climate Changes
Recording climate change methods: Tree rings - In a horizontal cross section cut from a tree trunk, variable width of rings are observed; these were produced by seasonal growth. The combination [...]