Gerald Haug is a paleoclimatologist, geologist and paleoceanographer. He studies the development of the Earth climate over thousands to millions of years. He analyses sediment cores from the sea floor and lakes, amongst several other climate archives. The chemical composition of the different sediment layers provides clues to the prevailing climatic conditions at the time of deposition. This allows quantitative reconstructions of past climate conditions and the underlying processes in the ocean, atmosphere and climate system.

The findings of paleoclimate research play a central role in the investigation of the causes of climate change and climate threshold levels, but especially with regard to understanding the dynamics of the climate system. Haug and his team were thus able to show that a more stable physical stratification of the water surface in the sub-arctic North Pacific, as well as in the Southern Ocean around the Arctic, reduced the biological activity of the cold periods. Questions about the reversibility of such abrupt climate thresholds are of considerable importance for the estimation of future climate scenarios especially in times of rapidly rising atmospheric greenhouse gas concentrations and the concomitant global warming.

In addition, Haug studied the interactions between climate and cultures. By investigating core samples from off the coast of Venezuela he was able to find evidence of historical periods of drought that were correlated in time with the fall of the Mayan civilization. Haug also found clues to the impact of climate change on historical developments in other regions, such as a relationship between times of weakened monsoons and the demise of several Chinese dynasties.