The Tropics in Paleoclimate

The past decade saw a surge in interest in the role of the Tropics in paleoclimate changes. This was motivated by the emergence of outstanding questions in paleoclimate that pointed to a role for the Tropics in addition to advances in tropical climate dynamics. This article reviews these developments, starting from a historical perspective. Three properties of tropical dynamics are prominent in paleoclimate: the sensitivity of the tropical climate to change; the ability of the tropical climate to reorganize; and the ability of the tropical climate to project its influence globally. The El Niño-Southern Oscillation (ENSO) system exemplifies these properties, making ENSO particularly prominent in paleoclimate. Summaries of three paleoclimate cases in which the science developed over the past decade—mid-Holocene ENSO, abrupt climate change during the most recent glacial period, and the mid-Pliocene permanent El Niño scenario—illustrate how the tropical hypothesis worked its way into paleoclimate research. This review closes with a discussion of prevailing views of the Tropics in the paleoclimate changes.