proxy climate indicators, definition of

Variables that are an indirect measure of some combination of climate-related variations back in time. These are used to determine temperature in a time when the thermometer was not yet invented. Examples include tree ring records, characteristics of corals, fraction of melted ice, concentration of salts and acids and the load of pollen trapped in air bubbles.

Note: Given these are indirect measures, the underlying accuracy of such measurements are not equivalent to direct measurement. Also the more indirect the measure (i.e. the more processes between what you are measuring and the temperature) the more inaccurate the representation of the temperature could be. Plus if one is not careful it is possible to 'cherry pick' your proxies to show (either knowingly or not) a pattern of temperatures not representative of the larger whole.

Related Tags: environment, climate