Above: Two bore holes taken from a fossil coral during coring on Fanning Island in the central Pacific

Why Study Paleoclimate?

Instrumental climate data only extend back to the mid-19th century, at best, which means that the anthropogenic climate change signals we are chasing are in most cases longer than the available climate records. A wealth of climate history can be extracted from geologic archives such as corals, deep-sea sediments, cave stalagmites, lake deposits, tree rings, and ice cores. Recent advances in research techniques mean that paleoclimate data have approached the resolution and fidelity of instrumental climate data. This is especially true in many remote regions of the world, where long, high-quality instrumental climate records are often lacking. Using meticulously calibrated climate “proxies”, paleoclimatologists construct centuries- to millennia-long timeseries of climatic histories. They use such records to quantify the range of natural climate variability, investigate the mechanisms of past global climate change events, and gauge the accuracy of computer simulations of past climate changes made under a variety of different climate forcings. The ultimate goal of paleoclimate research is to help identify the strengths and weaknesses of global climate models – models that are charged with projecting the future impacts of anthropogenic climate change. Such projections (and their uncertainties) are arguably the most important input for cost-benefit analyses designed to critically assess the consequences of climate change adaptation and/or mitigation strategies.