GISP2

GISP2, or Greenland Ice Sheet Project 2, was a major ice-core drilling project aimed at obtaining a long, high-resolution record of past climate from central Greenland. The drill site was near Summit, Greenland, and the program operated through the late 1980s into the early 1990s. The recovered core extended to roughly 1.7 to 1.8 kilometers in length and spans approximately 110,000 years of climatic history.

Researchers analyzed a range of proxies in the ice and trapped air. Stable isotopes of water (such as δ18O and δD) were used to infer past temperatures, while the chemistry of the air bubbles trapped in the ice provided records of atmospheric composition, including CO2 and methane. Additional data came from dust, sulfate and other soluble ions, and volcanic tephra layers that help with dating. The combination of these proxies yielded high-resolution information on both gradual climate trends and abrupt events.

GISP2 contributed significantly to understanding the last glacial-interglacial transition and the nature of abrupt climate changes. The core provided evidence of rapid, large-scale temperature fluctuations during the last glacial period and offered insights into the timing and structure of deglacial warming. The project helped establish methods and benchmarks for Greenland ice-core research and influenced subsequent programs, including other Greenland and Antarctic ice-core campaigns, advancing interpretations of how Northern Hemisphere climate interacts with global climate systems.

The project was a collaborative effort involving the U.S. Geological Survey, universities, and international partners, and its results continue to inform paleoclimate reconstructions, atmospheric science, and models of past and future climate variability.