Security First Corp safety through knowledge what is proxy data have you ever wondered how scientists figure out what the climate was like thousands or even millions of years ago it's a fascinating topic and the answer lies in something called proxy data proxy data is essentially a substitute for direct observations of the earth's climate since we can't travel back in time to measure the temperature or CO2 levels directly scientists use various natural records to reconstruct the past climate imagine walking through a forest and noticing the rings on a tree trunk these tree rings are like a natural calendar each ring representing one year of growth by analyzing the width and characteristics of these Rings scientists can infer information about past temperatures precipitation and even droughts another example is ice cores when scientists drill into ice sheets in places like Antarctica they collect long cores of ice that contain layers of ice from different years by analyzing the air bubbles trapped in these layers they can determine the CO2 levels and other atmospheric conditions from thousands of years ago ocean and Lake sediments are also valuable sources of proxy data these sediments contain pollen coral and other biological and chemical markers that provide clues about past climates for instance pollen from different plant species can tell us about the types of vegetation that existed in a particular area and by extension the climate conditions that supported those plants historical documents such as old Diaries log books and even paintings can also serve as proxy data for example English manorial accounts from the Middle Ages contain detailed records of harvests and milk production which can be used to reconstruct records of droughts and other climate related events these various types of proxy data are categorized into physical biological and chemical proxies physical proxies include things like sediment composition and magnetic properties while biological proxies include tree rings and pollen chemical proxies involve analyzing the chemical makeup of ice cores or ocean sediments by combining these different types of proxy data scientists can paint a comprehensive picture of the earth's climate history helping us understand how the climate has varied over time and how it might change in the future so the next time you hear about climate change remember that much of what we know comes from these natural record Keepers called proxy data thanks for tuning into our video please like And subscribe and leave a comment below see you in the next video