Climate - Distant and Recent Past

Climate - Distant and Recent Past

1. Distant

   • Evidence is available from many sources
     • Glacial moraines
     • Lake and ocean sediments
     • Pollen/Plant/Animal fossils
     • Deposits of insects
     • Tree rings
     • Coral Structure
     • Radiometric analysis of ice cores
     • Archealohical sites
   • Ice sheets
     • They are like a time capsule - the oldest layers of ice are on the bottom, the newest at the top
       • Trapped inside the ice layers are air bubbles (of CO2), these preserve air from the time of the snowfall.
         • Climatologists can reconstruct past temperature by drilling a core through the ice and measuring the amount of trapped CO2 in each layer

2. Recent

   • These are often not accurate, as they were not intended for climate records, but the can give a vague idea
   • This evidence suggests a rapid change in the types of climate - every few hundred years
   • Private Diaries
   • Ship logs
   • Accounts of military campains
   • Old photographs, drawings and paintings
   • Books and newspapers
   • Recorded dates of regular events such as harvests and tree blossoms
   • Agritulrual records
   • Tax ledgers