Climate, Environment and Society in the Pacific during the Last Millennium

Abstract

A major reason for writing this book is to describe the evidence for last-millennium climate change and its effects on environments and societies from the Pacific Basin, a commonly marginalized region in global syntheses. The paucity of palaeoclimate datasets from the southern hemisphere has often been remarked upon, and many palaeoclimatologists have cautioned that their statements about global last-millennium (and earlier) climate change should be regarded as preliminary until a better balance is achieved. Yet there is also a marked west-east hemispheric imbalance between the Pacific third of the Earth and elsewhere, largely because the Pacific is mostly ocean, but also because there have been fewer scientific investigations of its recent palaeoclimatic history. In seeking to redress these imbalances, this book utilizes data about Pacific Basin palaeoclimate from numerous sources. Many of these data are imprecise, their relationships to presumed climate drivers often uncertain. For such reasons, some of the conclusions reached about last-millennium Pacific Basin climates are less compelling than would be ideal, not just for comparing with other parts of the world but also for testing whether or not particular changes were global in extent, globally or hemispherically synchronous, or otherwise constrained in time or space. Yet there are more than adequate data to produce a first synthesis for this vast and poorly researched region, a synthesis that the author regards as sufficiently compelling to command the attention of geoscientists, climatologists, geographers, archaeologists, anthropologists, sociologists and historians interested in the Pacific. It is important to recognize that in the Pacific Basin – as in other parts of the world – the study of last-millennium climates is constrained by the effective reach of particular techniques back in time. Obviously, the last hundred years or so, for which there are instrumental records of climate in many places, is the least controversial time period. Beyond the reach of such directly monitored data series, it is necessary to use proxy data. There are three types of proxy used: those that directly proxy climate variables (typically temperature and precipitation), those that proxy climate through an environmental filter and finally those that proxy either climate or climate-driven environmental changes through changes in human societies.